| 荒牧 正俊（あらまき まさとし） | データ更新日：2024.04.18 |
助教 ／
工学研究院
材料工学部門
材料工学科
| 1. | Yuji SHIGETA, Naoyuki NOMURA, Katsuyoshi KONDOH, Kentaro UESUGI, Masato HOSHINO, Masatoshi ARAMAKI, Yukiko OZAKI, Use of X-ray CT imaging to quantitatively analyze the effects of the pore morphology on the tensile properties of CP-Ti L-PBF materials, ISIJ International, https://doi.org/10.2355/isijinternational.ISIJINT-2023-431, 64, 7, 1-10, 2024.05, Controlling the shape, size, and arrangement of residual defects (pores) in additivemanufactured materials is essential for improving their strength and reliability. However, quantifying the shape and arrangement of individual pores in such materials remains a challenge. This study aimed to clarify the effect of pore configurations that determine the tensile properties of laser powder-based fusion (L-PBF) materials. First, the 3D pore-configurations of pure titanium L-PBF materials fabricated under different beam energy densities were visualized using high-intensity X-ray computed tomography (CT). Subsequently, the porosity, volume equivalent diameter, and sphericity of each pore were quantified by 3D analysis of each CT image, and their correlations with the tensile properties were analyzed. The results showed that, unlike conventional sintered materials, the 0.2% yield stress did not correlate with the porosity of the specimen, suggesting heterogeneity in the hydrostatic component of stress acting on pores. This was connected to periodic fluctuation in the local porosity of the layers sliced perpendicular to the building direction. Furthermore, for specimens fabricated under relatively low beam energy densities, the porosity of the lowest density sliced layer was negatively correlated with tensile strength and total elongation, whereby the local low-density layer dominated the tensile properties. For specimens fabricated under the high energy densities where keyholes were generated, the maximum pore diameter rather than the local layer porosity was more predominate. Thus, it is evident that local structures such as local low-density regions or larger pores dominate the ductile properties of Ti L-PBF materials in terms of their tensile properties.. |
| 2. | Isshin Ando, Yasutaka Mugita, Kyosuke Hirayama, Shinji Munetoh, Masatoshi Aramaki, Fei Jiang, Takeshi Tsuji , Akihisa Takeuchi, Masayuki Uesugi and Yukiko Ozaki, Elucidation of pore connection mechanism during ductile fracture of sintered pure iron by applying persistent homology to 4D images of pores: Role of open pore, Materials Science & Engineering A, 10.1016/j.msea.2021.142112, 828, 1-8, https://doi.org/10.1016/j.msea.2021.142112, 2021.09, 4D pore configurations including an open pore were visualized by synchrotron X-ray laminography during the ductile fracturing process and then interpreted quantitatively using persistent homology (PH), a topological measure. In particular, this study used the zeroth PH, where the radius of an equivalent volume sphere for each pore and the distances to the other pores can be estimated for pairs of pores. The pore configurations were quantified as a set of birth and death values {(bi, di)} and changes due to increasing strain were tracked. As a result, the zeroth PH revealed the following information at the final stage before fracturing. First, the pair configurations between the open pore and closed pores decreased owing to the adsorption of closed pores by the open pore. Second, the configuration between the elongated closed pore and the open pore, where equivalent volume spheres are overwrapped, increased. These configurational changes in pores predict the pore connection between the open pore and surrounding closed pores that eventually generates a ductile crack perpendicular to the tensile stress. This study demonstrated the effective interpretation of the pore connection process that is essential to ductile crack generation.. |
| 3. | Y. Shigeta, Masatoshi ARAMAKI, K. Ashizuka, Y. Ikoma and Yukiko OZAKI, Effect of networked Cu-rich ferrite phase on proof stress and ultimate tensile strength of sintered bodies of Fe–Cu hybrid-alloyed steel powder with graphite, POWDER METALLURGY, 10.1080/00325899.2021.1871805, https://doi.org/10.1080/00325899.2021.1871805, 2021.01, To improve the yield strength of powder metallurgy steel, this work investigated the effect of a Cu-rich networked phase. Mixtures of 0.7% graphite and Fe–3% Cu hybrid-alloyed steel powders, composed of pre-alloyed Fe–3 x % Cu particles with diffusion-bonded 3(1 − x) % Cu (0 ≤ x ≤ 1), were processed by high-density compaction and conventional sintering. The maximum values of 0.2% proof stress (YS) and ultimate tensile strength (UTS) were obtained at x = 0.68, where high-density compact with well-networked Cu-rich ferrite phase was developed without Cu growth. Moreover, nanosized ε-Cu precipitates were observed in the Cu-rich ferrite. These high YS and UTS were achieved not only by decreases in porosity but also by precipitation strengthening caused by the nanosized ε-Cu in the Cu-rich ferrite network.. |
| 4. | Muhammad KOZIN, Keisuke KUSAKABE, Masatoshi ARAMAKI, Naoya YAMADA, Satoshi OUE, Yukiko OZAKI, Osamu FURUKIMI and Masaki TANAKA, Effect of Nitriding-Quenching and Carburizing-Quenching Processes on the Wear Resistance of Sintered Pure Iron, 粉体および粉末冶金, 67, 4, 173-181, Volume 67, 2019, pp. 173-181., 2020.04, The wear properties of sintered pure iron that were subjected to two different heat treatments, nitriding-quenching (NQ) and carburizing-quenching (CQ) were investigated. A martensite layer was formed on the surface layer in each treatment, but the hardness of the NQ martensite was much higher than that of the CQ martensite. On the other hand, the wear resistance of the CQ specimen was slightly higher than that of the NQ martensite, despite such lower value of initial hardness. The hardness after sling tests of the CQ surface remarkably hardened versus the NQ surface. EBSD analysis confirmed the plastic deformation on the CQ surface along the sliding direction, so the strain hardening might achieve better wear resistance. On the other hand, the NQ surface did not deform during sliding, and its wear might be influenced by the brittle fracture.. |
| 5. | Yasutaka MUGITA, Masatoshi ARAMAKI, Masayuki YAMAMOTO, Akihisa TAKEUCHI, Miyuki TAKEUCHI ,Takeshi Yokota, Yoshimasa FUNAKAWA, Osamu FURUKIMI, Void nucleation, and growth during tensile deformation of nanoscale precipitated steel and bainitic steel, ISIJ International, https://www.jstage.jst.go.jp/article/isijinternational/59/7/59_ISIJINT-2018-762/_article, 59, 7, 1362-1368, Vol. 59 (2019), Issue 7, Pages 1362-1368., 2019.07, [URL], A local elongation of 8% for nanoscale precipitated steel was observed via tensile testing,which is higher than that of 5% for bainitic steel. To determine the factor underlying this difference, void nucleation, growth, and coalescence mechanisms in the nanoscale precipitated steel and the bainitic steel were examined using electron backscattering diffraction and subsequent observation by synchrotron radiation X-ray laminography during tensile testing. Synchrotron radiation X-ray laminography analysis of void growth and coalescence revealed that the critical strain and the critical void volume fraction for fracture in the bainitic steel were smaller than those for the nanoscale precipitated steel. Secondary-ion mass spectrometry analyses revealed that C atoms were segregated at grain boundaries in the bainitic steel. Void nucleation sites in the nanoscale precipitated steel were nanoscale precipitates inside the grain and at grain boundaries and coarse precipitates; however, in the bainitic steel, void nucleation sites were entirely at grain boundaries. Nanoindentation hardness measurements showed a larger plastic strain gradient between the grain boundary and matrix in the bainitic steel than in the nanoscale precipitated steel. From these results, the high local elongation exhibited by the nanoscale precipitated steel was concluded to be due to the reduced plastic strain gradient with a uniform hardness distribution between the grain boundary and the grain interior..  |
| 6. | Y. Ozaki, Y. Mugita, M. Aramaki, O. Furukimi, S. Oue, F. Jiang, T. Tsuji, A., Takeuchi, M. Uesugi & K. Ashizuka, Four-dimensional observation of ductile fracture in sintered iron using synchrotron X-ray laminography, Powder Metallurgy, 10.1080/00325899.2019.1585032, 62, 2, 146-154, Volume 62, 2019 - Issue 2 pp. 146-154 ISSN: 0032-5899, 2019.03, Synchrotron X-ray laminography was used to examine the time-dependent evolution of the three-dimensional (3D) morphology of micropores in sintered iron during the tensile test. 3D snapshots showed that the networked open pores grow wider than 20 µm along the tensile direction, resulting in the internal necking of the specimen. Subsequently, these pores initiated the cracks perpendicular to the tensile direction by coalescing with the surrounding pre-existing microvoids or with the secondary-generated voids immediately before fracture. Topological analysis of the barycentric positions of these microvoids showed that they form the two-dimensional networks within the ∼20 µm of radius area. These observations strongly indicate that the microvoid coalescence could occur on shear planes formed close to the enlarged open pores or between closed pores by strain accumulation and play an important role in the crack initiation.. |
| 7. | Osamu FURUKIMI, Shun HARADA, Yasutaka MUGITA, Masatoshi ARAMAKI, Masayuki YAMAMOTO,
Akihisa TAKEUCHI, Miyuki TAKEUCHI ,Yoshimasa FUNAKAWA, Void Nucleation, Growth, and Coalescence Observed by Synchrotron X-ray Laminography during Tensile Deformation of Fe–0.02mass%N Alloy, ISIJ International, DOI: 10.2355, 58, 5, 943-951, Vol. 58 (2018), No. 5, pp. 943-951, 2018.05, In this study, the effect of the state of N atoms in a Fe–N alloy, namely, whether N exists as a dissolved atom or as a nitride on void nucleation, growth, and coalescence during tensile testing was examined and the factors dominating local elongation was discussed. Two types of Fe–0.02 mass% N alloy specimens were used; one was heated to the ferritic phase region before water-quenching, while the other was subjected to aging. The local elongation of the water-quenched specimen was lower than that of the aged specimen. Secondary-ion mass spectrometry and electron backscattering diffraction analyses revealed that N atoms were segregated around grain boundaries similarly in both the water-quenched and the aged specimens, while N atoms precipitated as Fe4N in the aged specimen. Void nucleation, growth, and coalescence were observed using synchrotron X-ray laminography. In the water-quenched specimen, voids suddenly grew and coalesced before fracture, while in the aged specimen sudden growth and coalescence were suppressed. Nano-indentation hardness measurements showed that the difference in hardness between the regions around the grain boundaries and grain centers was smaller in the aged specimen compared to that in the water-quenched specimen. This result indicated a lower plastic strain gradient around the grain boundaries in the aged specimen. This lower plastic strain gradient in the aged specimen was caused by precipitation of N atoms as Fe4N. From these results, it was concluded that the main factor permitting the greater local elongation of the aged specimen was the lower plastic strain gradient around the grain boundaries.. |
| 8. | M. Aramaki, M. Kozin, K. Yoshida, O. Furukimi, Effect of Nitriding-Quenching and Carburizing-Quenching on Wear Properties of Industrial Pure Iron, Journal of Heat Treatment and Materials, 10.3139/105.110346, 73, 3, 131-143, J. Heat Treatm. Mat. 73 (2018) 2, pp. 131-143, 2018.03, The wear properties of industrial pure iron treated by nitriding- quenching and carburizing-quenching were investigated. Both the nitrogen martensite and carbon martensite produced by each treatment exhibited the same high degree of wear resistance. The results of sliding tests showed that the nano-indentation hardness near the surfaces of both samples had increased. The surface hardening of the nitrogen martensite was more noticeable than that of the carbon martensite. EBSD analysis revealed that plastic strain had been induced on a relatively large scale (around 20 µm) after sliding in the case of the nitrogen martensite. It was found that the high wear resistance of the nitrogen martensite led to strain hardening through the effect of the load applied in the sliding test.. |
| 9. | 渡邊啓介, 井出洋文, 中崎盛彦, 竹内晃久, 荒牧 正俊, 古君 修, 熱間圧縮時の材料内部空隙変化の放射光X線ラミノグラフィー法による観察およびFEM解析, 鉄と鋼, 104, 2, Vol. 104, No. 2, pp65-71., 2018.02, 炭素鋼S25Cおよびステンレス鋼SUS316Lの鋼塊中心部に生成された空隙の熱間圧縮による形状変化を、放射光X線ラミノグラフィー法により逐次的に非破壊で三次元観察した。S25C、SUS316L ともに、初期を基準とした総体積比は加工量の増加に伴い減少した。一方、総数比はSUS316Lでは30%加工後に約30%まで減少したが、S25Cでは加工量が20%～30%の範囲で約90%の一定値を示した。この結果から、S25Cに比較してSUS316Lの方が空隙の閉塞が起こりやすいことが明らかになった。また、圧縮率が増加するとℓ/w(長軸/短軸長さ比)が2.5以上の高アスペクト比を有する空隙において分断が生じ、また、体積の大きい空隙ほど低い圧縮率で閉塞した。S25CとSUS316Lにおける閉塞性の差をFinite Element Method(FEM)により解析した結果、S25Cより加工硬化しにくいSUS316Lで静水圧積分が大きく、SUS316Lでボイドが閉塞しやすいという観察結果と一致した。. |
| 10. | Masayuki YAMAMOTO, Ryosuke Ochi, Kyono Yasuda, Masatoshi ARAMAKI, Shinji Munetoh, Osamu FURUKIMI, Effect of γ-Phase Stability on Local Deformation Energy of α-γ Duplex Stainless Steel, Materials Transactions, doi:10.2320/matertrans.H-M2017826, 58, 10, 1379-1385, 2017.10, The effect of austenite (γ) phase stability in the local deformation region on the deformation energy of ferrite (α)-γ duplex stainless steel is investigated using tensile testing. The uniform deformation energy values of both the γ-stable and unstable duplex stainless steels are similar, while the local deformation energy of γ-stable duplex stainless steel is larger than that of γ-unstable duplex stainless steel. In γ-unstable duplex stainless steel, the difference in nano-indentation hardness between the α and transformed martensite (α’) phases increases remarkably beneath the fractured surface. Low-voltage electron microscopy observations reveal that voids grow rapidly at the grain boundaries between the α and α’ phases beneath the fractured surface, resulting in a decrease in the local deformation energy in γ-unstable duplex stainless steel.. |
| 11. | 古君 修, 竹田祐二, 山本 正之, 荒牧 正俊, 宗藤 伸治, 井手洋文, 中崎盛彦, IF鋼の引張変形におけるボイド発生・成長挙動の放射光X線ラミノグラフィー法とEBSDによる解析, 鉄と鋼, 103, 8, 475-482, vol.103 No.8 pp.475-482. （早期公開2017.4.26 https://www.jstage.jst.go.jp/article/tetsutohagane/advpub/0/advpub_TETSU-2017-011/_article/-char/ja/） DOI : http://doi.org/10.2355/tetsutohagane.TETSU-2017-011, 2017.08, Ti 添加Interstitial Free (IF)鋼の伸び特性が優れている機構を、引張試験の局部伸び領域におけるボイドの発生および成長の観点から工業用純鉄と比較して解析した。ボイドの発生起点をElectron Back Scatter Diffraction (EBSD)解析を用い、また、成長挙動を放射光X線ラミノグラフィー法で調べた。 引張試験後の試料についてボイド生成起点をEBSD解析した結果によると、本試験に用いたIF鋼ではほぼ等しい割合でTiNおよび粒界であり、工業用純鉄では70%が大傾角粒界、30％が未再結晶粒界であった。引張試験を逐次途中止めして、放射光X線ラミノグラフィー法によりボイド成長挙動を調べた結果、IF鋼では破断直前でのボイドの連結が抑制されることが明らかとなった。引張試験を最大荷重で途中止めし、ナノインデンテーション硬さ試験を行い粒界からの硬さ(Hit)変化を測定したところ、工業用純鉄では粒界と母相とのHit差が大きく、均一変形領域においてすでに粒界近傍でのひずみ不均質化が生じているとの結論を得た。この不均質化が局部変形域でも影響を与え、IF鋼ではボイドの連結が抑制され、その結果、高い局部伸びを示したと考察された。. |
| 12. | 山本 正之, 原田 駿, 麦田 康敬, 荒牧 正俊, 古君 修, ナノインデンテーションによるFe-0.02mass%N合金の粒界の硬さ評価, 材料試験技術, 62, 3, vol.62 No.3 pp.173-177, 2017.07, Nano-indentation testing has been widespread in recent years. It makes it possible to examine hardness in a micro region, since the test force is１gf or lower. This study revealed that a hardness change between inner crystal grains and grain boundary in which a nitrogen atoms segregate can evaluate by using nano-indentation. In an electrolytic iron, nano-indentation hardness showed the same values on the grain boundaries and the inner grains. However, in Fe-0.02mass%N alloys in which nitrogen atoms segregation was expected on the grain boundary, hardness on the grain boundaries was higher than that in the crystal grains. Therefore, it was concluded that nano-indentation hardness is useful to examine the increase of hardness by the atoms segregation on the grain boundary.. |
| 13. | Osamu Furukimi, Kiattisaksri Chatcharit, Yuji Takeda, Masatoshi Aramaki, Shinji Munetoh, Masaki Tanaka, Void nucleation behavior of single-crystal high-purity iron specimens subjected to tensile deformation, Materials Science & Engineering A, 701, 221-225, Materials Science & Engineering A 701 (2017) 221–225., 2017.07, Void nucleation plays an important role for determining local deformation properties of ductile materials. In this study, the void nucleation behavior of single-crystal iron was examined in tensile tests. Two micrometer-size single crystals having a different type of slip extracted from electrodeposited pure iron were used to investigate the fracture mechanics during tensile deformation. Scanning electron microscopy (SEM) and high voltage electron microscopy (HVEM) images verified the existence of only a single slip system in the smaller specimen (cross-sectional area A = 16 μm2) and furthermore, no voids were observed. However, multiple slips and voids were observed in the larger specimen (A=28 μm2). These findings allowed us to reveal that multiple slips are a necessary criterion for void nucleation in single-crystal iron.. |
| 14. | Yuji Takeda, Kiattisaksri Chatcharit, Masatoshi Aramaki, Shinji Munetoh, Osamu Furukimi, Effects of tensile tests and specimen thickness on elongation and deformation energy for industrially pure iron, ISIJ International, 57, 6, Vol.57 (2017), No.6, pp. 1129-1137., 2017.06, Industrial pure iron specimens with a thickness that varied from 0.2 to 2.0 mm were investigated in tensile tests to examine the influence of specimen thickness on the percentage elongation and deformation energy. Conventionally, the total percentage elongation of a tensile specimen can be converted by Oliver’s equation, which is related to the tensile test specimen thickness. However, in this experiment, it was noticed that there were number of factors which led to the inaccuracy in the result. The total percentage elongation was influenced by the stress triaxiality. The FEM (Finite Element Method) analysis indicated that the stress triaxiality increased significantly with the thinner specimen. This was due to the void growth behavior, observed by SEM (Scanning Electron Microscope) under low voltage. These results revealed that voids nucleation and growth behavior influenced by the stress triaxiality were the main cause for the formula’s incompatibility. After completing the tensile test, the stress-strain curve can be obtained and categorized into the uniform and local deformation. The uniform deformation energy did not depend on the specimen thickness in contrast to duplex stainless steel, which was examined in our previous research. On the other hand, the local deformation energy lowered with the decrease in specimen thickness as with duplex stainless steel.These results indicated that the void nucleation and growth behavior had a significant impact on the total percentage elongation.. |
| 15. | Hirotsugu Tsuchida, Masatoshi Aramaki, Osamu Furukimi, Yoshimine Kato, Hydrogen Trap in Fine Ca(OH)2 Powder Made from Scallop-Shell Waste, ECS Transaction, 75, 31-38, 2017.1.1, 2017.01, Hydrogen trap was implied for calcium hydroxide Ca(OH)2 powder made form scallop (Patinopecten yessoensis) shell waste at high temperature of around 800°C to 900°C. Large quantities of seashells are abandoned every day and it is important to make use of them. The Ca(OH)2 powder was made by heating the fine grain scallop-shell powder up to about 1100°C and then quenched in water. Then the Ca(OH)2 powder was heated at temperature between 600 °C and 1300 °C for 30 min. in flowing Ar + 3% hydrogen gas. The hydrogen trap of the heat-treated scallop-shell powder was measured by using oxidation-reduction potential (ORP) analysis and nuclear magnetic resonance (NMR). At heat-treatment temperature of 900°C, the samples showed the lowest ORP that implies the highest adsorption of hydrogen. The NMR study also revealed an observation of sharp peaks at the 900°C, implying hydrogen trap as well.. |
| 16. | 竹田祐二, Chatcharit Kiattisaksri, 荒牧 正俊, 宗藤 伸治, 古君 修, 工業用純鉄の伸びおよび変形エネルギーに及ぼす引張試験片板厚の影響, 鉄と鋼, vol.102 No.10 pp.597-604., 2016.10, Industrial pure iron specimens with the thickness varied from 0.2 to 2.0 mm were investigated in tensile testing to examine the influence of specimen thickness on elongation and deformation energy. The total elongation was influenced by the stress triaxi. |
| 17. | 山本正之, 越智亮介, 安田恭野, 荒牧 正俊, 宗藤 伸治, 古君 修, フェライト-オーステナイト二相ステンレス鋼のオーステナイト安定性と局部変形エネルギー, 熱処理, 56巻、5号、pp285-291., 2016.10, Effect of austenite(γ)phase stability in local deformation region on deformation energy of ferrite(α)-γ duplex stainless steel obtained by tensile test was investigated. The results revealed that uniform deformation energy showed the same value for both γ-stable and unstable duplex stainless steels. On the other hand, local deformation energy of γ-stable duplex stainless steel was larger comparing γ-unstable duplex stainless steel. In γ-unstable duplex stainless steel, nano - indentation hardness difference between α and transformed martensite (α’) phases increased remarkably beneath fractured surface. Low voltage FE-SEM observations revealed that voids grew rapidly at the grain boundary between α and α’ phases beneath the fractured surface. From these results, it was concluded that the amount of local deformation energy in γ-unstable duplex stainless steel decreased due to the rapid void -growth at the grain boundary between α and α’ phases beneath the fracture surface.. |
| 18. | Osamu Furukimi, Hiroki Katafuchi, Masatoshi Aramaki, Muhammad Kozin, Satoshi Oue, Koki Yoshida, Ichito Narita, Naoya Yamada, Masayuki Yamamoto, Wear Resistance of Industrial Pure Iron Treated by Nitriding and Quenching Followed by Aging Process, Materials Transactions (Mater. Trans.), 57, 9, 1587-1592, Vol.57(2016), No.9, pp.1587-1592., 2016.09, The wear resistance of iron nitrides compound layers and a high nitrogen martensite phase formed in the material surface for industrial pure iron, treated by nitriding and quenching followed by aging process were studied experimentally. Both the compound layers consisted of fcc and hcp structures without pores by lowering the nitriding temperature and the high nitrogen martensite phase, showed the same tendency to high wear resistance. On the other hand, the pores in the compound layer made by the longer nitriding time decreased the wear resistance due to the acceleration of crack propagation. Metal flows were observed at the ε-phase in the compound layer very close to the surface after a sliding test. However, no strain hardening was observed. It was also found that the metal flows on a large part of the martensite layer and the hardness increased considerably. These results revealed that the high hardness ε-phase shows high wear resistance due to the plastic deformation, whereas the nitrogen martensite shows high wear resistance by the plastic deformation accompanied with the strain hardening.. |
| 19. | 髙宮 俊人, 石原 健, 宗藤 伸治, 山田 和広, 荒牧 正俊, 古君 修, 3%Si鋼中に析出したMnSeおよびMnSの地鉄との方位関係 , 熱処理, 56巻、1号、pp16-21., 2016.02, 方向性電磁鋼板のインヒビターとして利用されるMnSe,MnSの析出挙動は，二次再結晶に大きな影響を与える。このため，3%Si鋼中において加工熱処理後のMnSeおよびMnSの地鉄との方位関係を調査した。また，第一原理計算により析出物と地鉄との界面エネルギーを求め，考察をおこなった。 （1）TEMによる観察の結果，MnSeと地鉄との方位関係は，(001)α//(001)MnSe, [010]α//[010]MnSe, [100]α//[100]MnSであり，極めて高い配向関係が得られた。 （2）一方MnSは，MnSeと比較して，地鉄との配向性が低い結果が得られた。 （3）MnSおよびMnSeと地鉄との界面エネルギーを第一原理計算で算出した結果，MnSeの界面エネルギーはMnSに比べ小さくなり，上記配向性の差が生じる原因と考えられる。. |
| 20. | 阿部 幸佑, 岩城 将馬, 荒牧 正俊, 古君 修, 金崎 文雄, 高強度鋼板の液圧バルジ成形におけるスプリングバック挙動のFEM解析, 熱処理, 55巻、3号、pp189-195, 2015.06, ダイヤフラムの液圧バルジ成形におけるスプリングバック挙動を，FEM解析によって予測し，実際に成形した部品におけるスプリングバック量と比較を行った。吉田‐上森(Y-U)モデルを適用することで，実成部品のスプリングバック量を推定できることを示した。さらに，FEM解析により，鋼板の降伏点と引張強さ，金型肩部半径，成形液圧および鋼板‐金型間の摩擦がスプリングバック挙動に及ぼす影響を調べた。スプリングバック量をフランジ角と張出し高さで評価した結果，いずれも鋼板強度および成形液圧と線形性を有することが明らかとなった。また，上型肩部半径の影響はほとんど認められなかったが，一方，鋼板‐金型間の摩擦係数の影響は顕著であった。. |
| 21. | 古君 修, 片渕 紘希, 荒牧 正俊, Muhammad Kozin, 大上 悟, 吉田 幸樹, 成田 一人, 山田 直矢, 浸窒焼入れ-時効処理した工業用純鉄の耐摩耗特性 , 熱処理, 55巻、3号、pp172-180, 2015.06, 工業用純鉄に浸窒時効処理を施した時に鋼材表面に生成される鉄窒化物からなる化合物層および高炭素マルテンサイト層の無潤滑条件における耐摩耗特性について研究を行った。窒化処理の低温化によりボイドの生成を抑制した化合物層および高炭素マルテンサイト層は、いずれも同じ高い耐摩耗性を示した。一方、化合物層に多くのボイドが形成されると耐摩耗性は低下した。この現象は、潜在するボイドがき裂の進展を加速することに起因する。. |
| 22. | 平島拓弥, 荒牧 正俊, 山本正之, 安田恭野, 宗藤 伸治, 古君 修, 二相ステンレス鋼の変形エネルギーに及ぼす引張試験片板厚の影響, 鉄と鋼, vol.101 No.5 pp.308-314., 2015.05, Effect of specimen thickness on ductile fracture energy for ferrite-austenite duplex stainless steel was investigated by using tensile strain test. It was revealed that both uniform and local deformation energies decreased with the decrease in the specimen thickness. Voids in a thicker specimen can be easily formed at the lower plastic equivalent strain because of the steep increase in the triaxiality. The decrease in the local deformation energy was due to the void growth near the fracture surface depending on the steep increase in the stress triaxiality.. |
| 23. | Kousuke Abe, Hiroyuki Fukaura, Masatoshi Aramaki, Osamu Furukimi, FEM Analysis of Friction for Pressing Dies Controlled by Shot Treatment, Journal of Heat Treatment and Materials, 70, 1, Vol.70(2015), No.1, pp.26-32., 2015.01, The finite element method (FEM) analysis of elastic-plastic deformation was applied to examine the effect of surface texture controlling of dies by means of hybrid-shot treatment on the galling property applied to high tensile strength steel sheets. The FEM analysis results showed that the apparent friction coefficient, which was calculated from pressing load and the drawing force, increased with each increase in the pressing load. The experimental results from the drawing tests with lubricant oil showed that the friction coefficient of the die after hybrid-shot treatment decreased slightly with each increase of the pressing load. On the other hand, the friction coefficient of the die without shot treatment, (i.e. nearly flat surface), slightly increased with the increase of the pressing load due to the digging effect. These findings reveal that the effect of surface texture of dies was caused not only by the elastic-plastic deformation but also by the oil lubrication condition. The FEManalysis was therefore performed by taking into account the digging effect as well as the micro-oil pool effect. The experimental result in the case of hybrid-shot dies corresponds well to the FEM result by adopting the virtual oil model where the oil segment was defined as an elastic solid body.. |
| 24. | 荒牧 正俊, 内田 聡, 安田 恭野, 及川 誠, 古君 修, ナノインデンテーション硬さで評価した二相ステンレス鋼の引張変形とボイド発生挙動, 鉄と鋼, vol.100 No.10 pp.1261-1266, 2014.10, he plastic deformation behavior in a uniaxial tensile test was examined by applying the nano-indentation hardness test to the ferrite-austenite duplex stainless steel. Each phase revealed the same hardness and a different work hardening ratio. The effect of the hardness difference in each phase on the void nucleation process was investigated by means of EBSD analysis. From the EBSD analysis, deformation twinning and deformation-induced martensitic transformation were observed in the austenite phase near the fracture surface. The hardness of austenite rose to a higher degree than that of ferrite, and showed an extremely-high value due to martensitic transformation. The void appeared mainly at the interface between the martensite induced by deformation and the ferrite phases. Thus the void nucleation was enhanced by the martensitic transformation which occurred at the location of higher equivalent strain of 1.5.. |
| 25. | 古君修・新垣翔・山田直矢・荒牧正俊・大上悟・船川義正, 16%Crフェライト単相鋼の局部変形エネルギーとボイド生成挙動, 鉄と鋼, vol.99 No.1 pp60-69, 2013.01. |
| 26. | 内田聡・安田恭野・荒牧正俊・古君修, ナノインデンテーション試験における圧痕下の微小域塑性変形のEBSD解析, 熱処理, 52巻、5号、pp255-256, 2012.10. |
| 27. | Osamu Furukimi, Masatosi Aramaki, Kosuke Abe, Hiroyuki Fukaura and Naoya Yamada, Improvement of die life with surface texture control and solid lubricant, Journal of Heat Treatment and Materials, Vol.67, No.2, pp.153-157(2012), 2012.02. |
| 28. | Tomoaki Fukahori, Shinichi Suzuki, Naoya Yamada, Masatoshi Aramaki and Osamu Furukimi, Effect of Microstructure on Formation of Ductile Fracture Surface in Steel Plate, Advanced Materials Research (THERMEC 2011 Supplement), 10.4028/www.scientific.net/AMR.409.678, Vol. 409, (2012), pp678-683, 2012.01. |
| 29. | Kyono Yasuda, Satoshi Uchida, Masatoshi Aramaki and Osamu Furukimi, Examination of Plastic Deformation Behavior for Dual-Phase Steels by Nanoindentation Tests, Proc. of the 19th international conference on heat treatment and surface engineering and surface modification technologies congress (19th IFHTSE), Glasgow, (2011.10) , 2011.10. |
| 30. | Hirofumi Ide, Naoya Yamada, Masatoshi Aramaki, Masaki Tanaka, Makoto Oikawa and Osamu Furukimi, Study on ductile fracture behavior of Al-bearing duplex stainless steel, Proc. of the 19th international conference on heat treatment and surface engineering and surface modification technologies congress (19th IFHTSE), Glasgow, (2011.10) , 2011.10. |
| 31. | Yoshiyuki Kawaguchi, Naoya Yamada, Masatoshi Aramaki, Satoshi Oue, Masaki Tanaka and Osamu Furukimi
, Examination of ductile fracture mechanism for 0.2%C steels by void observation, Proc. of the 19th international conference on heat treatment and surface engineering and surface modification technologies congress (19th IFHTSE), Glasgow, (2011.10) , 2011.10. |
| 32. | Naoya Yamada, Shou Niigaki, Masatoshi Aramaki and Osamu Furukimi, Ductile Fracture Morphology and Void Formation in Local Deformation for Ferritic Steel, Proc. of the 19th international conference on heat treatment and surface engineering and surface modification technologies congress (19th IFHTSE), Glasgow, (2011.10) , 2011.10. |
| 33. | Masatosi Aramaki, Naoya Yamada and Osamu Furukimi, Effect of Combined Shot Treatment and Nitriding on Galling Property of Die used for High Strength Steels, The Iron and Steel Institute of Japan (ISIJ) International, Vol.51(2011), No.7, pp.1137-1141, 2011.07. |
| 34. | Masatoshi Ito, Yuma Honda, Masatoshi Aramaki, Yasushi Kato, Furukimi Osamu, The effect of Si on the precipitates for Nb bearing high-purity stainless steel, Journal of ASTM international, Vol. 8,No. 3 (Published Online 11 March 2011),Page Count 4,Paper ID JAI103250,2011.03., 2011.03. |
| 35. | Osamu Furukimi, Masatosi Aramaki, Kosuke Abe and Naoya Yamada, Improvement of die life with surface texture control and solid lubricant, Proc. of International Conference on "Heat Treatment and Surface Engineering of Tools and Dies" & European Conference on Heat Treatment "Quality in Heat Treatment" Wels, Austria, 2011.03., 2011.03. |
| 36. | Satoshi UCHIDA, Takasi YAMAMOTO, Masayuki YAMAMOTO, Masatoshi ARAMAKI, Yoshimine KATO, Kyono YASUDA and Osamu FURUKIMI, Nano-indentated Hardness of Bainite Phase in 0.8%C Dual Phase Steels, Proc. of International Conference on Advanced Steels (ICAS), Paper No. FR042, November, 2010, 2010.11. |
| 37. | Toshiyasu ETO, Naoya YAMADA, Yoshimine KATO, Masatoshi ARAMAKI, Yoshimasa FUNAKAWA and Osamu FURUKIMI, Fatigue Strength in High Strength Steel Sheet with a Punched Hole, International Conference on Advanced Steels (ICAS) 2010,2010.11., 2010.11. |
| 38. | Masatoshi Ito, Yuma Honda, Masatoshi Aramaki, Yasushi Kato and Osamu Furukimi, The effect of Si on the precipitates for Nb bearing high-purity stainless steel, Proc. of the 18th international conference on heat treatment and surface engineering and surface modification technologies congress (18th IFHTSE),pp.4902-4907,2010.07. , pp.4902-4907, 2010.07. |
| 39. | 鈴木伸一・山田直矢・荒牧正俊・古君 修・森戸 茂一, 二相組織鋼の延性破壊特性に及ぼすミクロ組織の影響, 熱処理, 50, 3, 210, Vol.50, No.3, pp210-214, 2010.6., 2010.06. |
| 40. | 本田佑馬・山田直矢・荒牧正俊・古君 修・及川 誠, 二相ステンレス鋼の基地組織変形挙動と延性破壊形成, 熱処理, 50, 3, 205, Vol.50, No.3, pp205-209, 2010.6., 2010.06. |
| 41. | Naoya Yamada, Masatoshi Aramaki and Osamu Furukimi, Fourier Analysis of Shot Treated Die Surface Texture, The 5th KIMS-Kyushu University(Research Center for Steel) Joint Symposium on Steel Research,2010.04., 2010.04. |
| 42. | Naoya Yamada, Masatoshi Aramaki, Yoshimasa Funakawa, Yasushi Katoh, Minoru Nakajima, Osamu Furukimi, Fourier Analysis of Ductile Fracture Surface for High-Cr Steel, 日本熱処理技術協会,熱処理Vol.49 Special Issue, pp533-536, 2009.10. |
| 43. | Osamu Furukimi, Masatoshi Aramaki, Naoya Yamada, Devlelopement of Long-Life Die used for Hign Strength Steels with Hybrid-Shot Treatment and Nitriding at Low Temperature, Proc. of the 4th Asian Conference on Heat Treatment and Surface Engineering (4th AHTSE), Beijing, (2009), 2009.10. |
| 44. | Yuma Honda, Naoya Yamada, Masatosi Aramaki, Makoto Oikawa, Osamu Furukimi, The Effects of Microstructures on the Ductile Fracture Surface Morphology in Duplex Stainless Steels, 日本熱処理技術協会,熱処理Vol.49 Special Issue, pp522-525, 2009.10. |
| 45. | Akira Ichikawa, Masatoshi Aramaki, Osamu Furukimi, The Stability of Austenite in Tensile Deformation and Its Relation to a Nitriding Treatment in Precipitation Hardened Stainless Steel, 日本熱処理技術協会,熱処理Vol.49 Special Issue, pp506-509, 2009.10. |
| 46. | Tomoki Nakao, Masatoshi Aramaki, Osamu Furukimi, Shigeru Unami, Effects of Graphite Diameter on the Strength of Ferrous Sintered Material, 日本熱処理技術協会,熱処理Vol.49 Special Issue, pp264-267, 2009.10. |
| 47. | 荒牧 正俊、中尾 友紀、宇波 茂、古君 修, Fe-Cu-C系焼結材料の引張強さに及ぼす添加黒鉛粒径の影響, 粉体および粉末冶金, 第56巻, 8号, pp495-501, 2009.08. |
| 48. | 荒牧正俊・堤 清一・山田直矢・宮原広郁・古君 修, 金型の摺動特性に及ぼす表面テクスチャーと窒化の影響, 熱処理, Vol.48, No.6, pp385-391, 2008.12., 2008.12. |
| 49. | Akira Ichikawa, Masatoshi Aramaki, Osamu Furukimi, The Stability of Austenite in Tensile Deformation and Its Relation to a Nitriding Treatment in Precipitation Hardened Stainless Steel, Proc. of the international conference on heat treatment and surface engineering and surface modification technologies congress (17th IFHTSE and SMT22), Kobe, 2008.10., 172-172, 2008.10. |
| 50. | Naoya Yamada, Osamu Furukimi, Masatoshi Aramaki, Yoshimasa Funakawa and Yasushi Katoh, Effect of Cr Precipitates Diameter on Local Elongation of High-Cr Steel, Proc. of the international conference on heat treatment and surface engineering and surface modification technologies congress (17th IFHTSE and SMT22), Kobe, 2008.10., 180-180, 2008.10. |
| 51. | Tomoki Nakao, Masatoshi Aramaki, Osamu Furukimi and Shigeru Unami, Effect of Graphite Diameter Added on the Strength of Ferrous Sintered Materials, Proc. of the international conference on heat treatment and surface engineering and surface modification technologies congress (17th IFHTSE and SMT22), Kobe, 2008.10., 204-204, 2008.10. |
| 52. | Yuma Honda, Naoya Yamada, Masatosi Aramaki, Makoto Oikawa and Osamu Furukimi, The effects of Al Content and Microstructures on the Ductile Fracture Behavior in Duplex Stainless Steels, Proc. of the international conference on heat treatment and surface engineering and surface modification technologies congress (17th IFHTSE and SMT22), Kobe, 2008.10., 176-176, 2008.10. |
| 53. | Naoya Yamada, Masatoshi Aramaki, Osamu Furukimi, Makoto Oikawa, Minoru Nakajima, Effect of Cu and AlN precipitates on Charpy ductile fracture propagation energy of steels, International conference on heat treatment and surface engineering and surface modification technologies congress, 2007.10, pp186, 2007.10. |
| 54. | 古君 修、荒牧 正俊, Ni鋼の脆性亀裂伝播停止特性に及ぼす結晶粒径の影響, 熱処理, Vol.47, No.2, pp66-70, 2007.04., 2007.04. |
| 55. | 小野寺龍太, 許 智泉, 荒牧正俊, Cu-Al合金のポルトヴァン-ルシャトリエ効果とコットレル理論への疑問, 日本金属学会誌, 66巻6号 pp627-633, 2002.06. |
| 56. | 小野寺龍太, 森田泉, 上木原竜太, 荒牧正俊, リューダース変形の特性と加工軟化モデルに基づいたそのシュミレーション方法の検討, 鉄と鋼, vol.87 No.11 pp719-726, 2001.11. |
| 57. | 小野寺龍太, 野々村 実奈展, 荒牧正俊, セレーション変形中の応力振動，リューダーズ歪および歪速度の測定, 日本金属学会誌, Vol.46 No.12 pp.1162-1171, 2000.01. |
| 58. | M. Aramaki, K. Higashida, R. Onodera, Influence of Carbon Content on Superplastic behavior in Ti and B added Cr-Mo Steels, Metallurgical and Materials Transactions A, 10.1007/s11661-999-0268-5, 30, 5, 1185-1191, Vol.30A No.5 pp.1185-1191, 1999.01. |
| 59. | M. Aramaki, R. Onodera, H. Era, K. Kishitake, Effects of co-addition of Titanium and Boron on microstructure of superplastic Cr-Mo steels, Material Science and Technology, 15, 12, 1408-1413, Vol.15 No.12 pp.1408-1413, 1999.01. |
| 60. | 荒牧正俊, 木村貴則, 森脇正義, 横手達夫, 小野寺龍太, 超塑性7475合金板のブロー成形性に及ぼす潤滑剤と金型角部形状の影響, 塑性と加工, Vol.39 No.452 pp.939-943, 1998.09. |
| 61. | 荒牧正俊, 中井 修, 小野寺龍太, 東田賢二, Ti B添加クロムモリブデン鋼の超塑性に及ぼす炭素含有量の影響, 鉄と鋼, Vol.83 No.12 pp.815-820, 1997.12. |
| 62. | 楊希強, 荒牧正俊, 小野寺龍太, 奥井徹, 横手達夫, 東田賢二, 圧延材の2枚板型破壊の力学的考察, 塑性と加工, Vol.38 No.438 pp.642-646, 1997.07. |
| 63. | 小野寺龍太, 加藤公彦, 松永秀一, 荒牧正俊, 東田賢二, 圧延されたAl合金のせん断帯と端割れの二，三の特徴, 塑性と加工, Vol.37 No.423 pp.379-384, 1996.04. |
| 64. | 小野寺龍太, 浜崎正直, 横手達夫, 荒牧正俊, 東田賢二, 鉛入りα黄銅の熱間加工に伴う破壊と加工性の改善, 塑性と加工, Vol.37 No.429 pp.1048-1052, 1996.01. |
| 65. | 荒牧正俊, 鋼の超塑性挙動に及ぼす炭素含有量の影響, フォームテックレビュー（天田金属加工機械技術振興財団） , 5, 1, 34-39, Vol.5 No.1 pp.34-39, 1994.01. |
| 66. | 小野寺龍太, 前原早苗, 横手達夫, 荒牧正俊, 表面積増加を目的とした超塑性アルミニウム合金板のガスブロー溝成形, 塑性と加工, Vol.40 No.458 pp.245-249, 1993.03. |
| 67. | 小野寺龍太, 外本和幸, 荒牧正俊, 軸対称金属複合材料の押出し加工中の欠陥発生の解析, 塑性と加工, Vol.33 No.376 pp.543-549, 1992.09. |
| 68. | 長 恒之, 江里口 正, 横手達夫, 荒牧正俊, 小野寺龍太, 粉末充填管のスエージング加工中の破壊の発生, 塑性と加工, Vol.33 No.380 pp.1051-1056, 1992.09. |
| 69. | 森部 毅, 高井良 昌文, 横手達夫, 荒牧正俊, 小野寺龍太, 軸対称金属複合材料の押出し加工中の欠陥発生に及ぼす芯材半径比の影響, 塑性と加工, Vol.33 No.376 pp.537-542, 1992.05. |
| 70. | 津島健次, 荒牧 正俊, 小野寺龍太, クロムモリブデン鋼の超塑性に及ぼすTi B添加の影響, 塑性と加工, 31, 352, 652-657, Vol.31 No.352 pp.652-657, 1990.05. |
| 71. | 田中えい士, 恵良秀則, 荒牧 正俊, 小野寺龍太, Cu添加低炭素鋼の鋼中Mn量によるCu析出挙動の変化, 九州大学工学集報, Vol.62 No.4 pp.363-367, 1989.01. |
| 72. | 荒牧 正俊, 林 安徳, 水素吸着による鉄蒸着膜の電気抵抗変化, 日本金属学会誌, 50, 3, 298-303, Vol.50 No.3 pp.298-303, 1986.01. |
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