Kyushu University Academic Staff Educational and Research Activities Database
List of Presentations
Satoshi Hata Last modified date:2018.07.02

Professor / Quantum Physicality Course / Department of Advanced Materials Science and Engineering / Faculty of Engineering Sciences


Presentations
1. Optimal conditions for electron microscopy observation of ferrous samples.
2. Recent advancement of electron tomography and its applications.
3. Orientation mapping of polycrystalline nanostructures by nanobeam electron diffraction.
4. Electron tomography: a method of three-dimensional imaging of nanostructure using TEM.
5. Developments in three-dimensional electron microscopy methods at Kyushu University.
6. Morphology of defects near surfaces of metals observed by TEM.
7. Current status of the Ultramicroscopy Research Center of Kyushu University.
8. Observation of microstructural evolution in heat-treatment processes of Bi-base superconducting films.
9. Dependence of heat treatment temperatures on microstructure in drawn pearlitic steel wires.
10. Topics on three-dimensional image reconstruction in electron tomography: from the viewpoint of materials research.
11. Advancements of 3D electron microscopy for nanostructural analysis.
12. Fabrication process and microstructure of bulk MgB2.
13. Fabrication of MgB2 wires using 11B isotope and their superconducting properties designed for fusion applications.
14. Microstructural evolution with low-temperature heat treatments in drawn pearlitic steel.
15. Microstructure and mechanical property of MgB2.
16. Influences of fabrication methods on microstructure of bulk MgB2.
17. Practical issues on electron tomography observation in iron-base samples.
18. Quantitative estimation of dislocation structure by SEM electron channeling contrast method.
19. Evaluation of kink deformation in Mg-Zn-Y alloy thin plates by four-point bending tests.
20. Change in crystallographic orientation distribution of ferrite in drawn pearlitic steel wire with low-temperature heat treatment.
21. Influences of coarse atomic clusters on strength and ductility in Al-Mg-Si alloy
.
22. Local microstructural change with creep deformation in Ni-base Alloy617.
23. Evaluation of kink deformation in Mg-Zn-Y alloy thin plates by four-point bending tests.
24. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Simulations of TDGL equations for B2 type ordering with two-step phase separation in Fe-Ni-Al alloys, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015, PTM 2015, 2015, The present authors recently developed a time-dependent Ginzburg-Landau (TDGL) formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. Kinetic equations for time-evolution of order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of a mean-field free energies and interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. Micro-structures in the superalloys consist of B2 ordered domains and A2 disordered matrices in the first stage of phase separation. The second stage during a subsequent aging leads to formation of B2 domains and A2 phase regions in the former A2 matrices and B2 domains, respectively. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors have applied the TDGL formulation to this alloy system, and performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
25. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Simulations of TDGL equations for B2 type ordering with two-step phase separation in Fe-Ni-Al alloys, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015, PTM 2015, 2015, The present authors recently developed a time-dependent Ginzburg-Landau (TDGL) formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. Kinetic equations for time-evolution of order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of a mean-field free energies and interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. Micro-structures in the superalloys consist of B2 ordered domains and A2 disordered matrices in the first stage of phase separation. The second stage during a subsequent aging leads to formation of B2 domains and A2 phase regions in the former A2 matrices and B2 domains, respectively. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors have applied the TDGL formulation to this alloy system, and performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
26. Methods of electron tomography observation for ferromagnetic materials.
27. Influences of Sc and Zr addition on microstructure and mechanical properties in Al-Mg-Mn alloy.
28. Quantitative evaluation of creep damage in polycrystalline Ni-base superalloys by SEM-EBSD analysis.
29. Precipitation behavior during long-time aging in Al-Mg-Si base alloy.
30. Novel three-dimensional imaging using electron beam.
31. Ken-ichi Ikeda, Rie Nishio, Hongye Gao, Satoshi Hata, Hideharu Nakashima, Three-dimensional analysis of kink bands in LPSO phase by using FIB-SEM, International Symposium on Long-Period Stacking Ordered Structure and Its Related Materials 2014 (LPSO2014), 2014.10.
32. Crystalline phase-orientation mapping of elasticity anormally Fe-Ni-Co-Ti based alloy after severe plastig deformation.
33. Influence of plastic-deformation processings on tensile deformation behavior in DP steel.
34. Relationship between high-temperature deformation behavior and microstructure in Zn-Al based alloys.
35. Influences of microstructural evolution on creep deformation behavior in high-Cr ferritic heat-registant steel.
36. Influence of alloying elements on mechanical properties in solid-solution strengthenined Ti alloys.
37. In-situ microstructural observation of Sn-Cu base device-contact alloy at high temperatures.
38. Influence of concentration of additional elements (Al,Cu) on mechanical properties.
39. Chemical state analysis of ferritic heat-resistant steel using XAFS.
40. Microstructural change in drawn pearletic steel wires by low-temperature heat treatments.
41. On the preferential growth directions on SrAl2O4:Eu mechano-luminescent material.
42. Influences of crystal interfaces on dislocation morphology in metal Mo.
43. Mechanical property of Zn-Al base alloy with a hypo-eutectic composition
.
44. Development and applications of transmission electron microscopy techniques for microstructural observations in metallic materials
.
45. Influence of mirror force on dislocations in molybdenum bicrystals
.
46. Microstructural observations of metallic materials using advanced transmission electron microscopy techniques.
47. Satoshi Hata, T. Nakano, U. D. Kulkarni, A. Arya, P. S. Gosh, G. K. Dey, H. Nakashima, Long-period superstructures and their ordering behaviour in Al-rich TiAl alloy: seeing nanostructure apart from phase diagrams, The International Union of Materials Research Societies (IUMRS) (THERMEC 2013) International Conference in Asia 2013, 2013.12.
48. Influence of mirror force on dislocations in molybdenum observed by electron tomography.
49. Satoshi Hata, U. D. Kulkarni, A. Arya, S. Matsumura, H. Nakashima, Ordering phenomena in alloys manifesting influences of long-range atomic interactions, International Conference on Processing & Manufacturing of Advanced Materials (THERMEC 2013), 2013.12.
50. Investigation of deformation mechanism of pure Ni under ultra-low creep-rates.
51. Influences of B/Mg ratios and starting powders on microstructure of in-situ MgB2 wires with Mg2Cu addition.
52. Satoshi Hata, Electron tomography observation of microstructure in crystalline materials, International Center for Materials Research (ICMR) Summer School on Materials in 3D: Modeling and Imaging at Multiple Length Scales, 2013.08.
53. Satoshi Hata, K. Sato, M. Murayama, H. Nakashima, Optimise electron tomography observation conditions for ferromagnetic samples: the case of ferritic steel, International Conference on Electron Microscopy and XXXIV Annual Meeting of the Electron Microscope Society of India (EMSI), 2013.07.
54. Application of TDGL model to two-step phase separation processes in Fe-Al-Ni alloys.
55. Influences of precipitates on creep fracture morphology of Ni-base Alloy 617.
56. Measurement of electron deflection in transmission electron microscopy observation of ferromagnetic materials.
57. Assessment of STEM tilt-series observation conditions for magnetic specimens.
58. Development of high-angle triple-axis specimen holders.
59. Study of electron tomography observation conditions for magnetic materials.
60. Satoshi Hata, Y. Shimada, T. Kajihara, K. Ikeda, H. Nakashima, K. Higashikawa, M. Inoue, T. Kiss, A. Matsumoto, H. Kitaguchi, H. Kumakura, T. Doi, J. H. Kim, S. X. Dou, Strategy of microstructural observation for the development of superconducting materials, 2013 MRS Spring Meeting & Exhibit, 2013.04.
61. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Application of TDGL model to B2 type ordering with two step phase separation in Fe-Ni-Al alloys, 21st International Materials Research Congress, IMRC 2012, 2013.01, Formation of domain structures in two-step phase separation in Fe-based Fe-Ni-Al alloys are investigated by applying a time-dependent Ginzburg-Landau (TDGL) model. The present authors recently developed a TDGL formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, multiple types of variants of the structures are represented by three order parameters which can be measured independently through crystal structure factors. Mean-field free energies are defined in a form of Landau type expansion with the order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
62. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Application of TDGL model to B2 type ordering with two step phase separation in Fe-Ni-Al alloys, 21st International Materials Research Congress, IMRC 2012, 2013.01, Formation of domain structures in two-step phase separation in Fe-based Fe-Ni-Al alloys are investigated by applying a time-dependent Ginzburg-Landau (TDGL) model. The present authors recently developed a TDGL formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, multiple types of variants of the structures are represented by three order parameters which can be measured independently through crystal structure factors. Mean-field free energies are defined in a form of Landau type expansion with the order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
63. Junjie Shen, Kenichi Ikeda, Satoshi Hata, Hideharu Nakashima, A new deformation region and how low do you go? - "intrinsic deformation limit", Chinese Materials Congress 2012, CMC 2012, 2013, The creep deformation in pure aluminum was investigated using helicoid spring samples at room temperature, 298 K, and σ < 1.19 MPa. It was found that the stress exponent is n = 0, which means the creep behavior in this region is independent on applied stress but some physical properties of materials. The creep behavior was suggested to be controlled by surface diffusion based on the strongly effect of surface area on creep behavior only in this creep region (n = 0). The threshold creep rate, th ∑th, called "intrinsic deformation limit", decided by surface diffusion was suggested. This discovery provided a new perspective to understand the extremely slow deformation in the nature..
64. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Simulations of structure formation in B2 type ordering with two step phase separation in Fe-Ni-Al alloys, 4th International Symposium on Slow Dynamics in Complex Systems: Keep Going Tohoku, 2013, The present authors recently developed a time-dependent Ginzburg-Landau (TDGL) formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, mean-field free energies are defined in a form of Landau type expansion with order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. Micro-structures in the super alloys consist of B2 ordered domains and A2 disordered matrices in the first stage of phase separation. The second stage during a subsequent aging leads to formation of B2 domains and A2 phase regions in the former A2 matrices and B2 domains, respectively. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors have applied the TDGL formulation to this alloy system, and performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
65. Junjie Shen, Kenichi Ikeda, Satoshi Hata, Hideharu Nakashima, A new deformation region and how low do you go? - "intrinsic deformation limit", Chinese Materials Congress 2012, CMC 2012, 2013, The creep deformation in pure aluminum was investigated using helicoid spring samples at room temperature, 298 K, and σ < 1.19 MPa. It was found that the stress exponent is n = 0, which means the creep behavior in this region is independent on applied stress but some physical properties of materials. The creep behavior was suggested to be controlled by surface diffusion based on the strongly effect of surface area on creep behavior only in this creep region (n = 0). The threshold creep rate, th ∑th, called "intrinsic deformation limit", decided by surface diffusion was suggested. This discovery provided a new perspective to understand the extremely slow deformation in the nature..
66. Ryuichiro Oguma, Syo Matsumura, Minoru Doi, Satoshi Hata, Keisuke Ogata, Simulations of structure formation in B2 type ordering with two step phase separation in Fe-Ni-Al alloys, 4th International Symposium on Slow Dynamics in Complex Systems: Keep Going Tohoku, 2013, The present authors recently developed a time-dependent Ginzburg-Landau (TDGL) formulation for ordering processes of B2 and D03 in binary alloys, taking into account the symmetrical relationships between these ordered phases. In this formulation, mean-field free energies are defined in a form of Landau type expansion with order parameters and a composition parameter. Interfacial energies due to local variations of degrees of order and composition are given in a gradient square approximation. Kinetic equations for time-evolution of the order parameters and the composition one are derived from the Ginzburg-Landau type potential consisting of the mean-field free energies and the interfacial energy terms. On the other hand, coauthors have investigated domain structures in two-step phase separation of Fe-based Fe-Ni-Al alloys. Micro-structures in the super alloys consist of B2 ordered domains and A2 disordered matrices in the first stage of phase separation. The second stage during a subsequent aging leads to formation of B2 domains and A2 phase regions in the former A2 matrices and B2 domains, respectively. The evolution of three-dimensional domain structures and composition profiles has been analyzed by electron tomography imaging and energy-dispersive X-ray spectroscopy. In this work the authors have applied the TDGL formulation to this alloy system, and performed three-dimensional numerical simulations assuming the thermal processing. The results of the simulations well reproduced the characteristics of the micro-structures obtained from the observations..
67. J. S. Barnard, J. H. Sharp, Satoshi Hata, Masatoshi Mitsuhara, Kenji Kaneko, K. Higashida, 3-dimensional imaging of dislocation microstructures by electron beams, 2011 MRS Fall Meeting, 2012.12, We review the progress in the electron tomography of dislocation microstructures in the transmission electron microscope (TEM). Dislocation contrast is visible both in conventional TEM and scanning TEM (STEM) modes and, despite the complicated intensity variations, dislocation contrast can be isolated using computational filtering techniques prior to reconstruction. We find that STEM annular dark-field (STEM-ADF) imaging offers significant advantages in terms of dislocation contrast and background artifacts. We present several examples, both in semiconducting and metallic systems, illustrating the properties of 3D dislocations. We present the high-angle triple-axis (HATA) specimen holder where the diffraction condition can be chosen at will and dislocation tomograms of multiple reflections can be combined. 3D dislocations are analyzed in terms of dislocation density and dislocation nodal structures. Several avenues of study are suggested that may exploit the 3D dislocation data..
68. J. S. Barnard, J. H. Sharp, Satoshi Hata, Masatoshi Mitsuhara, Kenji Kaneko, K. Higashida, 3-dimensional imaging of dislocation microstructures by electron beams, 2011 MRS Fall Meeting, 2012.12, We review the progress in the electron tomography of dislocation microstructures in the transmission electron microscope (TEM). Dislocation contrast is visible both in conventional TEM and scanning TEM (STEM) modes and, despite the complicated intensity variations, dislocation contrast can be isolated using computational filtering techniques prior to reconstruction. We find that STEM annular dark-field (STEM-ADF) imaging offers significant advantages in terms of dislocation contrast and background artifacts. We present several examples, both in semiconducting and metallic systems, illustrating the properties of 3D dislocations. We present the high-angle triple-axis (HATA) specimen holder where the diffraction condition can be chosen at will and dislocation tomograms of multiple reflections can be combined. 3D dislocations are analyzed in terms of dislocation density and dislocation nodal structures. Several avenues of study are suggested that may exploit the 3D dislocation data..
69. Preliminary observation of microstructure in materials by low-mag STEM.
70. Relationship between microstructure and heat treatment conditions of Bi,Pb-2223 thin films fabricated by sputtering methods.
71. The fabrication of high-Tc Bi,Pb2223 thin films by multilayer thin film method.
72. Electron microscopy observation of superconducting materials.
73. Electron tomography observation of two-step phase separation process in Fe-Al-Ni alloy.
74. Electron tomography observation of two-step phase separation process in Fe-Al-Ni alloy.
75. Two-step phase separation behavior in Fe- and Ni-base alloys.
76. Three-dimensional observation of lattice defects in crystals by electron tomography.
77. Tensile deformation behavior and microstructure in Al-Mg-Si base alloy after low-temperature aging.
78. Influences of alloying elements on high-temperature deformation behavior in hexagonal titanium.
79. Microstructural change during thermal fatigue in Sn-Cu base solider alloy.
80. Relationship between local change of crystalline texture and microstructure in SmBa2Cu3Oy superconducting tape.
81. Low-stress creep deformetion behavior in ferritic heat-resistant steel.
82. Microstructural observation of MgB2/Al thin films fabricated by an electron beam evaporation method.
83. Local crystallographic orientation analysis at punching regions in DP steel (quantification of large deformation dut to punching in DP steel (3)).
84. Takayoshi Nakano, Satoshi Hata, Koutarou Hayashi, Yukichi Umakoshi, Some long-period superstructures and the related motion of dislocations in Al-rich TiAl single crystals, 141st Annual Meeting and Exhibition, TMS 2012, 2012, Various long-period superstructures that appear in Al-rich TiAl are composed of three pairs of primitive cells, Ti 2Al, Ti 3Al, and Ti 4Al, having periodic atomic arrangements in unique shapes of lean rhombi, fat rhombi, and squares, respectively, on the (002) Ti layers. These primitive cells can produce long-period superstructures such as Al 5Ti 3, Al 3Ti 2, and h-Al 2Ti. The long-period superstructures play an important role in the operative deformation mode, configuration of dislocations, and related plastic deformation behavior in Al-rich TiAl, depending on the Al concentration. Fourfold ordinary dislocations, for example, often move as a group in the Al 5Ti 3 superstructure in the shapes of lean rhombi and squares embedded in the L1 0 matrix. In this study, the relationship between the periodic long-period superstructures and dislocation motion will be discussed from the viewpoint of anti-phase boundaries that form in each superstructure and their energies. The plastic deformation behavior in Al 5Ti 3 and h-Al 2Ti single-phase single crystals is also discussed..
85. Takayoshi Nakano, Satoshi Hata, Koutarou Hayashi, Yukichi Umakoshi, Some long-period superstructures and the related motion of dislocations in Al-rich TiAl single crystals, 141st Annual Meeting and Exhibition, TMS 2012, 2012, Various long-period superstructures that appear in Al-rich TiAl are composed of three pairs of primitive cells, Ti 2Al, Ti 3Al, and Ti 4Al, having periodic atomic arrangements in unique shapes of lean rhombi, fat rhombi, and squares, respectively, on the (002) Ti layers. These primitive cells can produce long-period superstructures such as Al 5Ti 3, Al 3Ti 2, and h-Al 2Ti. The long-period superstructures play an important role in the operative deformation mode, configuration of dislocations, and related plastic deformation behavior in Al-rich TiAl, depending on the Al concentration. Fourfold ordinary dislocations, for example, often move as a group in the Al 5Ti 3 superstructure in the shapes of lean rhombi and squares embedded in the L1 0 matrix. In this study, the relationship between the periodic long-period superstructures and dislocation motion will be discussed from the viewpoint of anti-phase boundaries that form in each superstructure and their energies. The plastic deformation behavior in Al 5Ti 3 and h-Al 2Ti single-phase single crystals is also discussed..
86. 3D observation of dislocations at grain boundary in Mo bicrystal after compressive deformation.
87. Three-dimensional visualization of nanostructure in crystals by electron microscopy.
88. Promising applications of advanced electron microscopy to bulk nanometals.
89. Creep deformation bahabior at ultra-low strain rates studied by helicoid spring creep tests.
90. Dislocation substructure and raft structure formed during creep deformation in Ni base superalloy.
91. Microstructure in Cu added MgB2 wire using a Mg2Cu compound as the additional source material.
92. Microstructural observation of MgB2 wires by x-ray computed tomography.
93. Microstructure in MgB2 thin film prepared on Al tapes.
94. Application of TEM tomography to crystal materials using diffraction contrast.
95. HVEM-EELS tomography observation of Ni-based alloys.
96. Microstructure in Mg2Cu-doped MgB2 superconducting wires.
97. Importance of macrostructural observation in MgB2 superconducting materials.
98. Microstructure and high temperature strength in ODS-9Cr ferritic steel.
99. Application of TEM tomography to crystal materials using diffraction contrast.
100. J. J. Shen, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Room temperature creep and substructure formation in pure aluminum at ultra-low strain rates, TMS 2011 - 140th Annual Meeting and Exhibition, 2011, The creep behavior in pure aluminum has been investigated by helicoid spring creep tests at strain rates, ε, lower than 10-10 s -1 and room temperature, 298 K. It was found that the creep behavior at the very low ε depends strongly on grain sizes and impurity concentrations: in high-purity aluminum (5 N Al) with an average grain size of 24 μm, the stress exponent was n ∼ 1; while, when the average grain size was larger than 1600 μm, the stress exponent was n ∼ 5. Microstructural observation shows the formation of large dislocation cells, 10 μm. On the other hand, in commercial low-purity aluminum (2 N Al) with the average grain size of 25 μm, the stress exponent was n = 2. Microstructural observations revealed dislocations emitted from grain boundaries and the formation of lattice dislocation cells. To evaluate creep deformation mechanisms of the pure aluminum, stress change tests were conducted during creep tests. It was revealed that the deformation in the range of the stress exponent, n ∼ 5, was controlled by recovery driven by internal stress, σi, because instantaneous strains at stress increment were larger than that at stress reduction. While the deformation behaviors in the ranges of the stress exponents, n ∼ 1 and n = 2, were in viscous manner, because instantaneous strains at stress increment and reduction were in the same level. Based on those experimental results, the creep mechanisms have been discussed..
101. J. J. Shen, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Room temperature creep and substructure formation in pure aluminum at ultra-low strain rates, TMS 2011 - 140th Annual Meeting and Exhibition, 2011, The creep behavior in pure aluminum has been investigated by helicoid spring creep tests at strain rates, ε, lower than 10-10 s -1 and room temperature, 298 K. It was found that the creep behavior at the very low ε depends strongly on grain sizes and impurity concentrations: in high-purity aluminum (5 N Al) with an average grain size of 24 μm, the stress exponent was n ∼ 1; while, when the average grain size was larger than 1600 μm, the stress exponent was n ∼ 5. Microstructural observation shows the formation of large dislocation cells, 10 μm. On the other hand, in commercial low-purity aluminum (2 N Al) with the average grain size of 25 μm, the stress exponent was n = 2. Microstructural observations revealed dislocations emitted from grain boundaries and the formation of lattice dislocation cells. To evaluate creep deformation mechanisms of the pure aluminum, stress change tests were conducted during creep tests. It was revealed that the deformation in the range of the stress exponent, n ∼ 5, was controlled by recovery driven by internal stress, σi, because instantaneous strains at stress increment were larger than that at stress reduction. While the deformation behaviors in the ranges of the stress exponents, n ∼ 1 and n = 2, were in viscous manner, because instantaneous strains at stress increment and reduction were in the same level. Based on those experimental results, the creep mechanisms have been discussed..
102. Achievements of TEM tomography observations for metallic materials.
103. Three-dimensional distribution of dislocations observed by TEM.
104. STEM imaging and its application to three-dimensional tomography for steel research.
105. Issues on image resolution of TEM-CT for materials characterization.
106. Critical current property and microstructure in MgB2 tape fabricated by an internal Mg diffusion method.
107. Evaluation of ultra-low strain rate deformation behavior at room temperature in high-purity aluminum.
108. Three-dimensional observation of dislocation microstructure in Ni-based superalloy after creep deformation.
109. Three-dimensional observation of aging-precipitation morphology of omega phases in beta-Ti and Zr alloys.
110. Influence of amounts of Al addition on high-temperature mechanical property in Mg-Al-Ca based die-casting alloys.
111. Evaluation of ultra-low strain-rate creep behavior of modified 9Cr-1Mo steel by helicoid spring creep tests.
112. High-temperature strength and microstructure in oxide-dispersion-strengthened heat-registant austenitic steel.
113. Characterization of metallic materials by TEM tomography.
114. Influence of Al addition on high-temperature deformation behavior of heat-resistant Mg alloys.
115. Spatial distribution of oxides and high-temperature strength in ODS ferritic steel.
116. Evaluation of creep deformation behavior under ultra-low strain rates by helicoid spring creep tests.
117. Applied Superconductivity Conference 2010.
118. High-temperature deformation behavior of heat-resistant Mg alloy with Sr addition.
119. Relationship between high-temperature deformation and microstructure in oxide-dispersion-strengthened austenitic heat-resistant steel.
120. Relationship between recrystallized microstructure and tensile-deformation behavior in 6000 series Al alloy with Sc and Zr additions.
121. Microstructural observation of initial stages of two-step phase separation in Ni-Al-Ti alloy by electron tomography.
122. Microstructure in MgB2 superconducting film after etching process to fabricate a micro-bridge shaped structure.
123. Observation of crystalline microstructures by energy-filtered HVEM.
124. High-angle triple-axis specimen holder and its applications.
125. Microstructure in MgB2 wires prepared by an internal Mg diffusion method.
126. Critical current properties and microstructural control in MgB2 superconducting films.
127. Assessment of creep properties under low-stress conditions in Pt based dispersion-strengthened alloys.
128. Dynamic microstructural change with creep deformation in lath martensites.
129. Change in dislocation density during annealing in pure Al for industrial applications after severe plastic deformation.
130. Analysis of distributions of crystallographic orientations in polycrystalline MgB2 superconducting bulks.
131. Evaluation of deformation behaviour under ultra-low strain rates in Al-Mg based alloys studied by a helicoid spring test method.
132. Relationship between ridging and texture in 6111 alloy.
133. Influence of precipitation morphology after aging on tensile deformation behaviour in Al-Mg-Si based alloys.
134. Development of TEM tomography observation of microstructure in crystals.
135. S. Sadamatsu, Masaki Tanaka, K. Higashida, Kenji Kaneko, Masatoshi Mitsuhara, Satoshi Hata, M. Honda, Crack tip dislocations observed by combining scanning transmission electron microscopy and computed tomography, 6th International Conference on Processing and Manufacturing of Advanced Materials - THERMEC'2009, 2010, Crack tip dislocations and dislocations introduced by three point-bending tests at high temperature are observed by combinating scanning transmission electron microscopy and computed tomography (STEM-CT). Commercially available P type (001) single crystal silicon wafers were employed. A series of STEM image was acquired from -60° to +60° in tilt range with 2° in tilt step. The diffraction vector was maintained close to g(hkl) = 220 during the acquisition by adjusting the [110] direction of the sample parallel to the tilt axis of the holder. Reconstructed images of dislocations revealed dislocation structures in three-dimension..
136. S. Sadamatsu, Masaki Tanaka, K. Higashida, Kenji Kaneko, Masatoshi Mitsuhara, Satoshi Hata, M. Honda, Crack tip dislocations observed by combining scanning transmission electron microscopy and computed tomography, 6th International Conference on Processing and Manufacturing of Advanced Materials - THERMEC'2009, 2010, Crack tip dislocations and dislocations introduced by three point-bending tests at high temperature are observed by combinating scanning transmission electron microscopy and computed tomography (STEM-CT). Commercially available P type (001) single crystal silicon wafers were employed. A series of STEM image was acquired from -60° to +60° in tilt range with 2° in tilt step. The diffraction vector was maintained close to g(hkl) = 220 during the acquisition by adjusting the [110] direction of the sample parallel to the tilt axis of the holder. Reconstructed images of dislocations revealed dislocation structures in three-dimension..
137. Possibility of three-dimensional observation in ODS-9Cr ferritic steel.
138. Enhancement of critical current density by controlling microstructure in MgB2 superconducting thin films.
139. Jc properties and microstructure in MgB2 bulks fabricated by a premix-PICT diffusion method.
140. High-temperature deformatioin of Pt-based dispersion-strengthened alloys.
141. STEM evaluation of dislocatioin density in crystalline grains of aluminium after after giant straining process.
142. Microstructural observation of MgB2 superconducting bulks fabricated by a PICT diffusion method.
143. Recrystallized microstructure in Al-Mg-Si alloy plates with Sc- and Zr-addition.
144. Experimental evaluation of the feasibility of three-dimensional reconstruction in electron tomography.
145. Experimental evaluation of the feasibility of three-dimensional reconstruction in electron tomography.
146. Three-dimensional observation of omega-phase in beta-Ti alloys.
147. Three-dimensional visualization of crystalline microstructures by transmissioin electron microscopy.
148. Three-dimensional analysis of omega-phase in beta-Ti alloys by dark-field TEM tomography.
149. Microstructural change with creep deformation and its quantification in high-Cr ferritic steel.
150. Quantification of lattice defects introduced by severe plastic deformation.
151. Correlation between stress component factor and threshold stress in creep deformation of ODS-9Cr ferritic steel.
152. High-temperature mechanical properties of Mg-Al-Ca alloys with different Al concentrations.
153. Evaluation of low-temperature creep behavior in 15Cr steel studied by helicoid spring tests.
154. Fundamentals of TEM tomography and its application to metals etc..
155. Low-temperature creep deformation behaviour of ODS ferritic steel studied by a helicoid spring creep testing method.
156. Precipitation behaviour and tensile deformation properties of 6000-class Al alloys.
157. Low-stress creep deformation behavioiur of 5000-class Al alloys.
158. Electron microscopy observation of oxygen distribution in MgB2 polycrystalline microstructures.
159. Quantitative evaluation of dislocation microstructure in steel by STEM tomography.
160. Three-dimensional analysis of omega phase in beta-Ti alloy by electron tomography.
161. Thin-film specimen preparation and transmission electron microscopy observation of bone using techniques of material characterization.
162. Microstructural observation of heat treatment processes in in-situ MgB2 tapes.
163. Recent findings in microstructural observations of MgB2.
164. Microstructural observation of heat treatment processes in in-situ MgB2 tapes.
165. Study on the accuracy of three-dimensional reconstructions in dark-field TEM tomography.
166. Quantitative evaluation of dislocation microstructure in steel by STEM tomography.
167. Three-dimensional analysis of omega phase in omega-Ti alloy by electron tomography.
168. Thin-film specimen preparation and transmission electron microscopy observation of bone using techniques of material characterization.
169. Characterization of metallic materials using TEM tomography.
170. Reduction of FIB damage layers using a plasma cleaner.
171. Electron microscopy observation of biological apatite in femur of mouse.
172. Precipitates morphology in Al-Mg-Si-Sc-Zr alloy after thermal rolling process.
173. Microstructural observation of SrAl2O4 stress-induced luminescent material.
174. Crystallographic microstructural changes in lath-martensite during creep deformation.
175. Evaluation of low-rate creep behaviour of high Cr steel by helicoid spring creep tests.
176. Electron tomography observation of microstructure in crystals.
177. H. Matsuo, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Stress-induced phase transformation in the vicinity of Vickers indentations in 10mol% CeO2 doped tetragonal ZrO2 polycrystal, 12th International Conference on Martensitic Transformations, ICOMAT-08, 2009, The stress-induced martensitic phase transformation from a tetragonal (t) phase to a monoclinic (m) phase in a CeO2 doped tetragonal polycrystal (Ce-TZP) was investigated from the view pints of characters of lattice correspondences (LCs) between tand m-phases and morphology of m-phase. Electron back scattering diffraction (EBSD) analysis in the vicinity of Vickers indentations in Ce-TZP reveled that there were three LCs, named LCA (type A), LCB (type B) and LCC (type C), where fractions of the three LCs were 12%, 8% and 80%, respectively. Morphology of m-phase showing each of the three LCs were observed by transmission electron microscopy (TEM). A single variant of mphase with lamellar plate-shaped morphology (m-plates) was formed near the Vickers indentations. In contrast, two variants of m-phases with twin relationships (m-twins) were formed far from the Vickers indentations. The infinitesimal-deformation theory was adopted to calculate scalar magnitude of internal stress within the m-plates and m-twins for each type of the LCs. Irrespective of morphology of the m-phase, the internal stress field for type C is a tensile stress field. Regardless of the type of LCs, absolute values of internal stress in the m-plates are higher than those in the mtwins..
178. H. Matsuo, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Stress-induced phase transformation in the vicinity of Vickers indentations in 10mol% CeO2 doped tetragonal ZrO2 polycrystal, 12th International Conference on Martensitic Transformations, ICOMAT-08, 2009, The stress-induced martensitic phase transformation from a tetragonal (t) phase to a monoclinic (m) phase in a CeO2 doped tetragonal polycrystal (Ce-TZP) was investigated from the view pints of characters of lattice correspondences (LCs) between tand m-phases and morphology of m-phase. Electron back scattering diffraction (EBSD) analysis in the vicinity of Vickers indentations in Ce-TZP reveled that there were three LCs, named LCA (type A), LCB (type B) and LCC (type C), where fractions of the three LCs were 12%, 8% and 80%, respectively. Morphology of m-phase showing each of the three LCs were observed by transmission electron microscopy (TEM). A single variant of mphase with lamellar plate-shaped morphology (m-plates) was formed near the Vickers indentations. In contrast, two variants of m-phases with twin relationships (m-twins) were formed far from the Vickers indentations. The infinitesimal-deformation theory was adopted to calculate scalar magnitude of internal stress within the m-plates and m-twins for each type of the LCs. Irrespective of morphology of the m-phase, the internal stress field for type C is a tensile stress field. Regardless of the type of LCs, absolute values of internal stress in the m-plates are higher than those in the mtwins..
179. Electron microscopy observation of growth of biological apatite crystals with preferential crystallographic orientation.
180. Observation conditions for convergent beam electron diffraction patterns of body-centered cubic iron.
181. Analysis of grain boundary characteristics in polycrystalline MgB2 bulks.
182. Creep deformation behabior of Mg-Al-Ca alloys.
183. Electron microscopy observation of biological apatite crystals and their growth with preferential crystallographic orientation.
184. Electron tomography observation of dislocation microstructure in steels.
185. Microstructure of Al-Mg-Si based alloy plates with co-addition of Sc and Zr.
186. TEM/STEM observation of microstructure in pure copper after HPT processing.
187. Microstructure of Al-Mg-Si based alloy plates with co-addition of Sc and Zr.
188. Long-period superstructure phases and their defect structures in Al-rich TiAl.
189. Attempt of three-dimensional visualization of dislocation structure in metals by electron tomography.
190. Creep deformation behaviour in Mg-Al-Ca based die-casting alloy.
191. Fracture surface observation in ceramics using electron tomography.
192. Three-dimensional electron tomography analysis of crac tip dislocations.
193. Three-dimensional microstructure observation in Ni4Mo ordering alloy by dark-field TEM tomography.
194. Creep behaviour analysis in SUS304 steel by a helical spring creep testing method.
195. Influences of normalizing and tempering temperatures on creep strength in 10Cr-1Mo-V-Nb steel.
196. Electron microscopy study of microstructure in bone by researchers of materials.
197. Present status of three-dimensional visualization by 3D-TEM.
198. New approach to microstructure analysis in steel using nano-probe electron microscopy techniques.
199. Analysis of creep deformation behavior in SUS304 steel by a creep test using coil-shaped specimens.
200. Deformation behavior and microstructure under tensile and compressive stress in AX type Mg alloys.
201. Microstructure observation of pure copper after HPT processing.
202. Crystallization behavior in amorphous Si thin films induced by local stress.
203. Microstructure change in 6000 Al alloy with addition of Sc and Zr.
204. Electron tomography analysis of dislocations at adges of cracks in Si single crystal.
205. Mechanical properties of high density MgB2 bulk.
206. Influence of doping with carbon compounds on microstructure in MgB2 tape.
207. Composition dependence on microstructure in MgB2 film fabricated by electron beam evaporation.
208. Jc-B characteristics of alternately-layered MgB2/Ni thin films.
209. Crystallographic orientation relationships and stress field under stress-induced phase transformation in CeO2-doped tetragonal ZrO2 porycrystal.
210. TEM observation of endochondral ossification regions of rat.
211. Observation of deformed microstructures containing large strain using a STEM diffraction contrast method.
212. Relationship between creep strength and omega values in high-Cr and high-temperature ferritic steel.
213. Formation process of cubit orientation texture in Al-Mg-Si alloys.
214. Changes in Ni3Al/Ni dual phase microstructure with severe cold rolling and heat treatments.
215. H. Matsuo, Masatoshi Mitsuhara, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Electron microscopy analysis of crack propagation behavior of alumina, Materials Science and Technology Conference and Exhibition, MS and T'08, 2008, Macroscopic features of crack propagation behavior in polycrystalline alumina (poly-alumina) and alumina single crystals (single-alumina) were analyzed by scanning electron microscopic electron back-scattered diffraction (SEM-EBSD) analysis. It was revealed that the intergranular fracture behavior is independent on grain boundary characters. When the cracks are propagated in the grains of poly- or single-alumina, zigzag cracks were produced. The zigzag cracks are composed of fracture surfaces formed along the cleavage planes. Microscopic features of fracture surfaces formed in a single-alumina were observed in detail by electron tomography combined with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). It was by visualized that the zigzag cracks were composed of flat and uneven fracture surfaces at a nm scale. The flat fracture surfaces and uneven ones were nearly parallel to the cleavage plane, {11̄02}, and the basal plane, {0001}, respectively..
216. Ram Kishore, Renu Sharma, Satoshi Hata, Noriyuki Kuwano, Yoshitsuga Tomokiyo, Hameed Naseem, W. D. Brown, In-situ transmission electron microscopy investigation of aluminum induced crystallization of amorphous silicon, 2008 MRS Spring Meeting, 2008, The interaction of amorphous silicon (a-Si) and aluminum (Al) has been examined using in-situ transmission electron microscopy. Carbon coated nickel grids were used for depositing thin (∼50nm) amorphous silicon films using ultra high vacuum cluster tool and a thin film of Aluminum (∼50nm) was deposited subsequently on a-Si film by sputtering. The grid containing a-Si and Al films was mounted on a heating holder of FEI 200kV TEM and loaded in the TEM for viewing the microstructural and phase transformations during the in-situ heating process. The microstructural features and electron diffraction patterns in the plain view mode were observed with increase in temperature starting from 30 °C to 275 °C. The temperatures used in this experiment were 30,100,150,200, 225, 275°C . A sequential change in microstructural features and electron diffraction pattern due to interfacial diffusion of boundary between Al and amorphous Si was investigated. Evolution of polycrystalline silicon with randomly oriented grains as a result of a-Si and Al interaction was revealed. After the in-situ heating experiment the specimen was taken out and etched to remove excess of Al and the subjected to high resolution imaging under TEM and EDS analysis. The EDS analysis of the crystallized specimen was performed to locate the Al distribution in the crystallized silicon. It has been shown that Al induced crystallization can be used to convert sputtered a-Si into polycrystalline silicon as well as nanocrystalline silicon at a temperature near 275 °C by controlling the in-situ annealing parameters. The mechanism of AIC has been discussed from the experimental results and the phase diagram of Al-Si system..
217. H. Matsuo, Masatoshi Mitsuhara, K. Ikeda, Satoshi Hata, Hideharu Nakashima, Electron microscopy analysis of crack propagation behavior of alumina, Materials Science and Technology Conference and Exhibition, MS and T'08, 2008, Macroscopic features of crack propagation behavior in polycrystalline alumina (poly-alumina) and alumina single crystals (single-alumina) were analyzed by scanning electron microscopic electron back-scattered diffraction (SEM-EBSD) analysis. It was revealed that the intergranular fracture behavior is independent on grain boundary characters. When the cracks are propagated in the grains of poly- or single-alumina, zigzag cracks were produced. The zigzag cracks are composed of fracture surfaces formed along the cleavage planes. Microscopic features of fracture surfaces formed in a single-alumina were observed in detail by electron tomography combined with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). It was by visualized that the zigzag cracks were composed of flat and uneven fracture surfaces at a nm scale. The flat fracture surfaces and uneven ones were nearly parallel to the cleavage plane, {11̄02}, and the basal plane, {0001}, respectively..
218. Ram Kishore, Renu Sharma, Satoshi Hata, Noriyuki Kuwano, Yoshitsuga Tomokiyo, Hameed Naseem, W. D. Brown, In-situ transmission electron microscopy investigation of aluminum induced crystallization of amorphous silicon, 2008 MRS Spring Meeting, 2008, The interaction of amorphous silicon (a-Si) and aluminum (Al) has been examined using in-situ transmission electron microscopy. Carbon coated nickel grids were used for depositing thin (∼50nm) amorphous silicon films using ultra high vacuum cluster tool and a thin film of Aluminum (∼50nm) was deposited subsequently on a-Si film by sputtering. The grid containing a-Si and Al films was mounted on a heating holder of FEI 200kV TEM and loaded in the TEM for viewing the microstructural and phase transformations during the in-situ heating process. The microstructural features and electron diffraction patterns in the plain view mode were observed with increase in temperature starting from 30 °C to 275 °C. The temperatures used in this experiment were 30,100,150,200, 225, 275°C . A sequential change in microstructural features and electron diffraction pattern due to interfacial diffusion of boundary between Al and amorphous Si was investigated. Evolution of polycrystalline silicon with randomly oriented grains as a result of a-Si and Al interaction was revealed. After the in-situ heating experiment the specimen was taken out and etched to remove excess of Al and the subjected to high resolution imaging under TEM and EDS analysis. The EDS analysis of the crystallized specimen was performed to locate the Al distribution in the crystallized silicon. It has been shown that Al induced crystallization can be used to convert sputtered a-Si into polycrystalline silicon as well as nanocrystalline silicon at a temperature near 275 °C by controlling the in-situ annealing parameters. The mechanism of AIC has been discussed from the experimental results and the phase diagram of Al-Si system..
219. Three-dimensional structure analysis of dislocations using an ADF method.
220. New functions of the JEM-1300NEF high-voltage electron microscope.
221. High-resolution electron microscopy observation of tetragonal/monoclinic interfaces in CeO2-doped tetragonal ZrO2 porycrystals.
222. In-situ EBSD observation of formation processes of cubit orientation texture in 6000 aluminum alloy.
223. EBSD analysis of behavior of stress corrosion cracking in austenitic high-temperature steel.
224. Evaluation of occupation sites of oxygen atoms in InN crystal.
225. High-temperature deformation mechanism in Mg-Al-Ca-Sn die-cast alloy under low-stress conditions.
226. Formation process of cubic orientation texture in 6000 aluminum alloy.
227. TEM observation of high-density MgB2 bulk.
228. Superconducting properties in MgB2+x non-stoichiometric thin films.
229. Dependence of Jc on magnetic field in MgB2/B multilayered films.
230. Electron microscopy observation of formation and crystallographic orientations of hydroxyapatite crystals in the region of endochondral ossification.
231. Development of electron tomography techniques for intermetallic materials.
232. Phase separation of gamma and gamma’ phases in Ni-Si-Fe alloy.
233. Microstructural changes with oxydation and condensation processes near Si/SiGe hetero-interfaces.
234. Analysis of creep deformation behavior under low-stress in Sn-Ag-Cu alloys by creep experiments using coil-shaped specimens.
235. Three-dimensional electron tomography observation of high-Cr ferritic high-temperature steel with V and Nb addition.
236. Microstructure observation of superconductors by transmission electron microscopy.
237. Creep strengthening mechanism in high-Cr ferritic high temperature steel with V and Cr addition.
238. High-temperature deformation mechanism in Mg-Al-Ca-Sn die-cast alloy.
239. Analysis of low-stress creep deformation mechanism in Sn alloys by creep experiments using coil-shaped specimens.
240. Three-dimensional electron tomography observation of high-Cr ferritic high temperature steel.
241. Three-dimensional TEM observation of phase separation of ’ particles in Ni-Al-Ti alloys.
242. Jc-B property of MgB2 thin film with nanometre-sized Ni layers introduced as artificial pinning centers..
243. TEM/STEM observation of Cu precipitates and dislocations in Fe-Cu alloy.
244. FIB-TEM observation of microstructures near a growth plate of a femur of mouse.
245. Observation of three-dimensional microstructures of ordered domain variants using dark-field TEM tomography.
246. Attempt of microstructure observation of hard tissues using FIB-TEM.
247. Three-dimensional morphorogy analysis of gamma particles precipitated from gamma' phase in Ni-Al-Ti alloy.
248. Dependence of heat treatment conditions on Al2Ti-type long-period ordered state in TiAl single crystal with composition gradient.
249. Three-dimensional domain structure in alloys observed by TEM.
250. Electron microscopy observation of Cu particles and dislocations in Fe-3 mass% Cu alloy.
251. TEM analysis of site-occupancy of oxygen in InN thin film fabricated by MBE method.
252. Three-dimensional microstructure analysis of crystalline materials using electron tomography.
253. Influence of oxgen atoms introduced in III-group nitride crystal on its physical property.
254. Microstructures of MgB2 thin films fabricated with introducing oxygen.
255. Microstructure observation of MgB2 thin film with introducing nanometre-sized Ni layers.
256. TEM observation of in-situ MgB2 tape doped with thiophene.
257. Introduction of pinning centers into MgB2 thin film using nanosized layered structures.
258. Pinning effect of very thin Ni-layers inserted with a interval of 15 nm in MgB2 superconducting film.
259. Properties of microstructures in MgB2 observed by TEM (Part 2).
260. Three-dimensional observation of ordered domain structures by dark-field TEM tomography.
261. Microstructures of outer pressure-type whiskers grown on tin plates.
262. Influence of one-direction diffusion on long-period ordering in Al-rich TiAl single crystal.
263. Three-dimensional observation of Ni4Mo-type ordered domain structure using dark-field TEM tomography.
264. Electron microscopy observation of interactions between dislocations and Cu particles in Fe-Cu alloy.
265. TEM analysis of nano-SiC doped MgB2 superconducting tapes.
266. Microstructural features of MgB2 studied by TEM.
267. Formation of APBs in higher-order superstructure phases and controlling long-period superstructures.
268. Assessment of observation conditions for dark-field TEM tomography of ordering alloys.
269. FIB-TEM analysis of microstructural changes with nano-SiC doping in in-situ MgB2 tapes.
270. Three-dimensional observation of microstructures in ordering alloys -attempt of dark-field TEM tomography-.
271. Influence of disperesion of Cu nanoparticles on tensile deformation behaviour in steel.
272. Influence of Cu segregation at grain boundaries on grain growth of austenite.
273. H. Sosiati, Satoshi Hata, N. Kuwano, Y. Iwane, Y. Morizono, Y. Ohno, Microstructural characterization of whiskers and oxidized surfaceson Sn/FeNi42 and Pb-free alloys, 20th Annual Passive Components Symposium, CARTS-Europe 2006, 2006, Microstructural characterization was performed by analytical transmission electron microscopy (ATEM) to clarify the formation mechanism of tin whiskers. A tin (Sn)-layer about 10 μm thickness was electrodeposited on a FeNi42 plate. The Sn/FeNi42 plate was heated and cooled repeatedly in a temperature range of 233-403 K for 100 cycles under various atmospheres. Cross-sectional TEM specimens of whiskers on the Sn/FeNi42 plate were prepared using a focused ion beam (FIB) micro-sampling technique. Some artifact-effects of the FIB treatments on microstructures in tin alloys were taken into account. Bent-type whiskers grown on the Sn/FeNi42 are of polycrystalline β-Sn. A tin-oxide layer around 10 nm in thickness is formed on the tin surface. Electron diffraction, high-resolution TEM and electron energy loss spectroscopy (EELS) analyses revealed that the tin-oxide layer is predominantly of crystalline SnO 2. The presence of crystalline SnO was also recognized. It was found that the tin-oxide layer tends to be rather thin around stems of the whiskers. It is interpreted that thermal stress in the tin-layer breaks the thin tin-oxide layer at grain boundaries of tin and the whiskers grow from the broken area. The formation mechanism of the whiskers is discussed..
274. H. Sosiati, N. Kuwano, Satoshi Hata, Y. Iwane, Y. Morizono, Y. Ohno, Tin whisker formation on a lead-free solder alloy studied by transmission electron microscopy, 2006 8th Electronics Packaging Technology Conference, EPTC, 2006, Tin whiskers grown on a Sn/Cu-plated Polyimide (PI)-flexible substrate are a serious problem in electronic industrial application, because the whiskers lead to catastrophic electrical short circuit failures. Here, we report characterization of microstructures in the whiskers grown on a surface of Sn/Cu-plated PI-flexible substrate by cross-sectional transmission electron microscopy (TEM) to analyze the behavior and the formation mechanism of whiskers. The whisker was found to be monocrystalline β-Sn and grown with the preferred directions of [110] and [101]. The whiskers formed on this tin surface are nucleated and grown by the compressive stress, that is induced externally by insertion of Sn/Cu-plated PI-flexible substrate into the connector..
275. H. Sosiati, Satoshi Hata, N. Kuwano, Y. Iwane, Y. Morizono, Y. Ohno, Microstructural characterization of whiskers and oxidized surfaceson Sn/FeNi42 and Pb-free alloys, 20th Annual Passive Components Symposium, CARTS-Europe 2006, 2006, Microstructural characterization was performed by analytical transmission electron microscopy (ATEM) to clarify the formation mechanism of tin whiskers. A tin (Sn)-layer about 10 μm thickness was electrodeposited on a FeNi42 plate. The Sn/FeNi42 plate was heated and cooled repeatedly in a temperature range of 233-403 K for 100 cycles under various atmospheres. Cross-sectional TEM specimens of whiskers on the Sn/FeNi42 plate were prepared using a focused ion beam (FIB) micro-sampling technique. Some artifact-effects of the FIB treatments on microstructures in tin alloys were taken into account. Bent-type whiskers grown on the Sn/FeNi42 are of polycrystalline β-Sn. A tin-oxide layer around 10 nm in thickness is formed on the tin surface. Electron diffraction, high-resolution TEM and electron energy loss spectroscopy (EELS) analyses revealed that the tin-oxide layer is predominantly of crystalline SnO 2. The presence of crystalline SnO was also recognized. It was found that the tin-oxide layer tends to be rather thin around stems of the whiskers. It is interpreted that thermal stress in the tin-layer breaks the thin tin-oxide layer at grain boundaries of tin and the whiskers grow from the broken area. The formation mechanism of the whiskers is discussed..
276. H. Sosiati, N. Kuwano, Satoshi Hata, Y. Iwane, Y. Morizono, Y. Ohno, Tin whisker formation on a lead-free solder alloy studied by transmission electron microscopy, 2006 8th Electronics Packaging Technology Conference, EPTC, 2006, Tin whiskers grown on a Sn/Cu-plated Polyimide (PI)-flexible substrate are a serious problem in electronic industrial application, because the whiskers lead to catastrophic electrical short circuit failures. Here, we report characterization of microstructures in the whiskers grown on a surface of Sn/Cu-plated PI-flexible substrate by cross-sectional transmission electron microscopy (TEM) to analyze the behavior and the formation mechanism of whiskers. The whisker was found to be monocrystalline β-Sn and grown with the preferred directions of [110] and [101]. The whiskers formed on this tin surface are nucleated and grown by the compressive stress, that is induced externally by insertion of Sn/Cu-plated PI-flexible substrate into the connector..
277. Optimization of observation conditions for dark-field TEM tomography of ordering alloys.
278. Influence of kinetics on microstructure formation in ordering alloys -long-period ordering in Al-rich TiAl alloy-.
279. STEM-EDX analysis of Cu at austenite grain boundaries.
280. Effect of addition of SiC nano-particles on microstructures and superconducting properties in MgB2 tapes.
281. Microstructural Study of SiC-doped MgB2/Fe Superconducting Tapes Fabricated by in situ Powder-in-tube Process.
282. Effect of plasma cleaning on damage layers of FIB-prepared specimens.
283. Observation of ordered and disordered domain particles in Ni-Al-Ti alloys by dark-field TEM tomography.
284. Ordering Process and Formation of Anti-Phase Boundary in Long-Period Superstructures of Al-Rich TiAl Single Crystals.
285. Three-Dimensional Observation of Ordered and Disordered Precipitates Using Dark-Field TEM Tomography.
286. Fabrication of LiCoO2 nano-particles using an excess Li method.
287. Damaged microstructure in A335B steel (2)- STEM observation.
288. Effect of nano-SiC doping on microstructure of in situ powder-in-tube MgB2 tape.
289. Microstructures of MgB2 Superconducting Films Fabricated by in situ EB and ex situ PLD Techniques.
290. Attempt of improving TEM image quality of FIB-prepared specimens by plasma cleaner.
291. Observation of γ and γ' precipitates in Ni-Al-Ti alloy by dark-field TEM tomography.
292. Nanostructure analysis of Cu-Ti-based bulk metallic glass by transmission electron microscopy.
293. Takayoshi Nakano, Yosuke Nagasawa, Yukichi Umakoshi, Satoshi Hata, Noriyuki Kuwano, Masaru Itakura, Yoshitsugu Tomokiyo, Ordering process and formation of anti-phase boundary in long-period superstructures of Al-rich TiAl single crystals, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005, 2005, Ordering process and subsequent formation of anti-phase boundaries (APBs) in the long-period superstructures of X3Ti2 (Ga 3Ti2), X5Ti3 (Al5Ti 3) and h-X2Ti (h-Al2Ti) in -rich TiX (X=Al or Ga) single crystals were examined by a high-resolution transmission electron microscopy. Formation of the APBs is closely related to the unique units of ordered base clusters such as Ti4X, Ti3X and Ti 2X which form square, fat rhombus and lean rhombus shapes, respectively, in the (002) Ti-rich layers of the L10 matrix. The Al5Ti3-type anti-phase domains (APDs) with various sizes in diameter are introduced in Ti-62.5at.%Al crystals by appropriate heat treatment. Almost all the X5Ti3-type APBs lie on {110) and a type of APB (named Type A) with the extremely low APB energy was found. In contrast, no APBs are introduced in X3Ti2 and h-X 2Ti because of their relatively higher energies compared with those in X5Ti3. As a result, the L10 matrix phase remains between APDs as a thin boundary phase for h-Al2Ti..
294. Satoshi Hata, K. Kimura, Syo Matsumura, Y. Tomokiyo, T. Moritani, M. Doi, Three-dimensional observation of ordered and disordered precipitates using dark-field TEM tomography, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005, 2005, For three-dimensional (3D) observation of microstructures in ordering alloys, such as orientation variants and anti-phase domain boundaries, electron tomography using dark-field transmission electron microscopy (DF TEM) may be a potential approach. However, DF TEM tomography has been thought to be impossible because of dynamical diffraction effects in crystals. In this study, we attempted DF TEM tomography of ordered and disordered precipitates in Ni-Mo and Ni-Al-Ti alloys. A tilt series of DF images of the precipitates were obtained by precisely setting diffraction conditions for a superlattice reflection. Owing to a long extinction distance of the superlattice reflection, dynamical diffraction effects, such as thickness fringes, have been effectively suppressed. Preliminary 3D reconstruction from the obtained tilt series clearly shows qualitative morphology and relative positions of the precipitates, which suggests the feasibility of the DF TEM tomography for ordering alloys..
295. Takayoshi Nakano, Yosuke Nagasawa, Yukichi Umakoshi, Satoshi Hata, Noriyuki Kuwano, Masaru Itakura, Yoshitsugu Tomokiyo, Ordering process and formation of anti-phase boundary in long-period superstructures of Al-rich TiAl single crystals, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005, 2005, Ordering process and subsequent formation of anti-phase boundaries (APBs) in the long-period superstructures of X3Ti2 (Ga 3Ti2), X5Ti3 (Al5Ti 3) and h-X2Ti (h-Al2Ti) in -rich TiX (X=Al or Ga) single crystals were examined by a high-resolution transmission electron microscopy. Formation of the APBs is closely related to the unique units of ordered base clusters such as Ti4X, Ti3X and Ti 2X which form square, fat rhombus and lean rhombus shapes, respectively, in the (002) Ti-rich layers of the L10 matrix. The Al5Ti3-type anti-phase domains (APDs) with various sizes in diameter are introduced in Ti-62.5at.%Al crystals by appropriate heat treatment. Almost all the X5Ti3-type APBs lie on {110) and a type of APB (named Type A) with the extremely low APB energy was found. In contrast, no APBs are introduced in X3Ti2 and h-X 2Ti because of their relatively higher energies compared with those in X5Ti3. As a result, the L10 matrix phase remains between APDs as a thin boundary phase for h-Al2Ti..
296. Satoshi Hata, K. Kimura, Syo Matsumura, Y. Tomokiyo, T. Moritani, M. Doi, Three-dimensional observation of ordered and disordered precipitates using dark-field TEM tomography, International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2005, 2005, For three-dimensional (3D) observation of microstructures in ordering alloys, such as orientation variants and anti-phase domain boundaries, electron tomography using dark-field transmission electron microscopy (DF TEM) may be a potential approach. However, DF TEM tomography has been thought to be impossible because of dynamical diffraction effects in crystals. In this study, we attempted DF TEM tomography of ordered and disordered precipitates in Ni-Mo and Ni-Al-Ti alloys. A tilt series of DF images of the precipitates were obtained by precisely setting diffraction conditions for a superlattice reflection. Owing to a long extinction distance of the superlattice reflection, dynamical diffraction effects, such as thickness fringes, have been effectively suppressed. Preliminary 3D reconstruction from the obtained tilt series clearly shows qualitative morphology and relative positions of the precipitates, which suggests the feasibility of the DF TEM tomography for ordering alloys..