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阪本 辰顕サカモト タツアキ

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大学院理工学研究科 物質生命工学専攻
職名講師
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Last Updated :2017/12/02

研究者基本情報

学歴

  •  - 2005年, 大阪大学, 工学研究科, マテリアル科学専攻
  •  - 2002年, 大阪大学, 工学研究科, マテリアル科学専攻
  •  - 2000年, 大阪大学, 工学部, 材料物性工学科

経歴

  •   2011年, - 愛媛大学大学院理工学研究科
  •   2007年,  - 2011年,  愛媛大学大学院理工学研究科
  •   2006年,  - 2007年,  愛媛大学大学院理工学研究科
  •   2005年,  - 2006年,  愛媛大学工学部機能材料工学科
  •   2003年,  - 2005年,  大阪大学 大学院 工学研究科 マテリアル科学専攻

所属学協会

  • 日本金属学会
  • 日本鉄鋼協会
  • Materials Research Society
  • 軽金属学会
  • 日本顕微鏡学会

委員歴

  •   2010年, 軽金属学会, 中国四国支部 経理担当幹事

研究活動情報

研究キーワード

    Ti基構造材料, V基およびW基核融合炉材料

論文

MISC

  • 鉄鋼材料におけるオーステナイト中の転位網の応力場による粒内 ベイナイト生成
    阪本 辰顕、小西早苗、中西祐太、吉澤俊希、平本貴史、大藤弘明, 愛媛大学地球深部ダイナミクス研究センター先進超高圧科学研究拠点 (PRIUS)成果報告書,   2015年
  • 転位網を利用した粒内ベイナイト生成とその機械的性質への効果
    阪本辰顕,小西早苗,中西祐太,吉澤俊希.平本貴史, 大阪大学接合科学研究所共同利用報告書,   2015年
  • マグネシウム合金の結晶粒微細化に及ぼすイットリウム添加効果
    阪本辰顕, 松本拓也,小原明日人, 大阪大学接合科学研究所共同利用報告書,   2015年
  • 耐中性子照射性に優れる先進的鉄鋼材料と高融点合金の微細組織と強度特性
    阪本 辰顕、仲井 清眞、栗下 裕明、松尾 悟、渡辺 英雄, 九州大学応用力学研究所共同利用研究成果報告書,   2015年
  • メカニルアロイング法により作製した耐熱アルミニウム合金の微細組織評価
    阪本辰顕, 綷谷将太, 大阪大学接合科学研究所共同利用報告書,   2015年
  • ナノ組織を有するバナジウム合金の機械的性質と微細組織に及ぼす中性子照射効果
    阪本辰顕, 仲井清眞, 小林千悟, 栗下裕明, 鳴井實, 山崎正徳, 外山健, 東北大学金属材料研究所附属量子エネルギー材料科学国際研究センター共同利用研究経過報告書(CD-ROM), 2014,   2015年
  • ニアαチタン合金の高温降伏強度に及ぼす初期組織の影響
    阪本辰顕, 松村裕, 大塚尚平, 小林千悟, 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • フォノン分散関係に基づくTi合金準安定相生成に及ぼす合金元素添加効果の解析
    小林千悟, 菅生三月, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • 各種純金属及び金属酸化物上への骨芽細胞接着性評価
    山内勇樹, 小林千悟, 岡野聡, 岡本威明, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • Ti‐(2.0,2.5)Mo‐(0~2)Fe合金の機械的特性に及ぼす内部組織の影響
    宮本晃, 小林千悟, 岡野聡, 阪本辰顕, 池田勝彦, 上田正人, GEPREEL Mohamed Abdel‐Hady, IBRAHIM Mervat M., 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • Ti‐Mo‐Fe合金のω相生成に及ぼす組成および熱処理の影響
    真鍋慶祐, 小林千悟, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • Ti‐Mo合金のβ相からの焼入組織形成に及ぼすAl添加効果
    十亀宏明, 小林千悟, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 155th,   2014年09月10日
  • ベイナイト鋼中のオーステナイトにおける転位網生成
    平本貴史, 仲井清眞, 阪本辰顕, 小林千悟, 材料とプロセス(CD-ROM), 27,   2014年09月01日
  • 18Crステンレス鋼中のLaves相析出初期過程の結晶学的解析
    百田陽平, 小林千悟, 仲井清眞, 阪本辰顕, 材料とプロセス(CD-ROM), 27,   2014年09月01日
  • マルテンサイト変態させたニアαチタン合金の微細組織と高温引張特性
    松村裕, 阪本辰顕, 仲井清眞, 小林千悟, 材料とプロセス(CD-ROM), 27,   2014年09月01日
  • ベイナイト鋼の強靭化に及ぼすオーステナイト中の転位網の効果
    小西早苗, 仲井清眞, 阪本辰顕, 小林千悟, 材料とプロセス(CD-ROM), 27,   2014年09月01日
  • ベイナイト鋼中のオーステナイトへの転位網導入過程とその強靭化に及ぼす効果
    吉澤俊希, 仲井清眞, 阪本辰顕, 小林千悟, 材料とプロセス(CD-ROM), 27,   2014年09月01日
  • ナノ組織を有する高融点遷移金属の微細組織に及ぼす中性子照射効果
    阪本辰顕, 栗下裕明, 山崎正徳, 仲井清眞, 小林千悟, 鳴井實, 外山健, 東北大学金属材料研究所附属量子エネルギー材料科学国際研究センター共同利用研究経過報告書(CD-ROM), 30th,   2014年06月
  • Ti合金α”相生成組成範囲に及ぼすβ相安定化元素の影響の第一原理的解釈
    小林千悟, 菅生三月, 仲井清眞, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 154th,   2014年03月07日
  • Ti‐2Ag‐8X(X=Zr,Ta,Mn)合金の陽極酸化皮膜の構造と光触媒活性
    菊池武倫, 小林千悟, 岡野聡, 仲井清眞, 阪本辰顕, 日本金属学会講演概要(CD-ROM), 154th,   2014年03月07日
  • 強磁性形状記憶Fe‐31.2Pd合金単結晶の磁場・応力下でのバリアント再配列
    阪本辰顕, 福田隆, 掛下知行, 岸尾光二, 日本金属学会講演概要, 133rd,   2003年10月11日
  • 強磁性形状記憶Fe3Pt単結晶における磁場誘起歪の温度・方位依存性
    福田隆, 阪本辰顕, 掛下知行, 岸尾光二, 日本金属学会講演概要, 133rd,   2003年10月11日
  • 強磁性形状記憶Fe‐Pd合金におけるf.c.t.マルテンサイト相の応力―歪曲線
    よし中圭一, 阪本辰顕, 福田隆, 掛下知行, 岸尾光二, 日本金属学会講演概要, 132nd,   2003年03月27日
  • 強磁性形状記憶Fe3Ptにおける磁場誘起歪の結晶方位依存性
    井上哲也, 阪本辰顕, 福田隆, 掛下知行, 岸尾光二, 日本金属学会講演概要, 132nd,   2003年03月27日
  • 電子線ホログラフィーとローレンツ顕微鏡法によるFePd合金の磁区構造評価
    村上恭和, 進藤大輔, 阪本辰顕, 福田隆, 掛下知行, 日本金属学会講演概要, 131st,   2002年11月02日
  • 磁場によるFe‐Pd合金単結晶のマルテンサイトバリアント変換に及ぼす方位依存性
    阪本辰顕, 鈴江文平, 福田隆, 掛下知行, 竹内徹也, 岸尾光二, 日本金属学会講演概要, 131st,   2002年11月02日
  • Nd4.5Fe77B18.5合金の析出ナノ粒子組織および結晶構造 (II)
    阪本辰顕, 花田剛, 石丸学, 金清裕和, 広沢哲, 弘津禎彦, 日本金属学会講演概要, 130th,   2002年03月28日
  • 研究生活1年目を終えて
    阪本 辰顕, 社団法人軽金属学会軽金属, 56,   2006年08月30日
  • High Temperature Deformation of a Fine-Grained and Particle-Dispersed V-2.3%Y-4%Ti-3%Mo Alloy
    Tatsuaki Sakamoto, Hiroaki Kurishita, Sengo Kobayashi, Kiyomichi Nakai, Hideo Arakawa, Hideki Matsui, 日本金属学会, 47, (10) 2497 - 2503,   2006年10月01日, The high temperature deformation behavior of a fine-grained and particle-dispersed V-2.3%Y-4%Ti-3%Mo (mass%) alloy was investigated. The alloy was fabricated by powder metallurgical methods utilizing mechanical alloying and hot isostatic pressing (HIP), followed by annealing at 1273 K for 3.6 ks. Tensile tests were performed at temperatures from 873 to 1273 K at initial strain rates from 2.5 × 10 -5 to 1.0 × 10 -1 s -1 . X-ray diffraction analyses show that the HIPed and annealed specimens contain a significant amount of (Y, Ti) 2 O 3 and small amounts of YN, Ti 2 O 3 and TiO. Transmission electron microscopy observations show that the matrix contains approximately 3%Ti and 3%Mo in solution and that the average diameters of the matrix grains and dispersoids are about 620 and 42 nm, respectively. Tensile test results show that the yield stress depends strongly on test temperature and strain rate. From the dependence of the yield stress measured at 1073 and 1273 K on plastic strain rate, it is found that the dependence is divided into three regions with different deformation controlling mechanisms: a recovery controlling process of a long range internal stress field associated with dispersed particle (the high-strain-rate region), grain boundary sliding (the medium-strain-rate region) and presumably solute atmosphere dragging (the low-strain-rate region). Effects of 4%Ti addition on the microstructures and high temperature deformation behavior are discussed. © 2006 The Japan Institute of Metals.
  • Martensitic Transformation in Shape Memory Alloys under Magnetic Field and Hydrostatic Pressure
    Tomoyuki Kakeshita, Takashi Fukuda, Tatsuaki Sakamoto, Tetsuya Takeuchi, Koichi Kindo, Syouichi Endo, Kohji Kishio, 日本金属学会, 43, (5) 887 - 892,   2002年05月01日, Effects of magnetic field and hydrostatic pressure on martensitic transformation have been examined by using Fe-Pt, Cu-Al-Ni, Ni 2 MnGa and Fe-Pd shape memory alloys and Fe-Ni alloys. Following results are obtained; (i) in Fe-Pt, Cu-Al-Ni and Fe-Ni alloys, the experimental magnetic field and/or hydrostatic pressure dependence of martensitic transformation start temperature, M s , is in good agreement with the dependence calculated by the equation previously proposed by our group to evaluate the relation between M s and magnetic field and hydrostatic pressure. (ii) Giant magnetostriction has been observed in the martensite state of Ni 2 MnGa and Fe-31.2 at%Pd ferromagnetic shape memory alloy single crystals. The values (contraction of 3.8% for Ni 2 MnGa and expansion of about 3% for Fe-31.2 at%Pd) are nearly the same values as can be expected from the perfect conversion of variants, i.e., variants are converted to preferable variants whose magnetocrystalline anisotropy energy is minimum among them under the magnetic field.
  • Magnetic field-induced strain in iron-based ferromagnetic shape memory alloys
    SAKAMOTO T, FUKUDA T, KAKESHITA T, TAKEUCHI T, KISHIO K, American Institute of PhysicsJournal of Applied Physics, 93, (10,Pt.3) 8647 - 8649,   2003年05月15日, Magnetic field-induced strain in iron-based ferromagnetic shape memory alloys was studied. The conversion of variants by magnetic field is almost perfect for Fe-31.2Pd and is not perfect for Fe 3 Pt. It was found that the recoverable strain in the field removing process is small for Fe-31.2Pd and is about 0.6% for Fe 3 Pt.
  • Influence of Magnetic Field Direction on Rearrangement of Martensite Variants in an Fe-Pd Alloy
    Tatsuaki Sakamoto, Takashi Fukuda, Tomoyuki Kakeshita, Tetsuya Takeuchi, Kohji Kishio, 日本金属学会, 44, (12) 2495 - 2498,   2003年12月01日, Influence of magnetic field direction on rearrangement of martensite variants in an Fe-31.2Pd(at%) single crystal has been investigated using thermal expansion measurement in a cooling process under the magnetic field applied along [001] P , [011] P and [111] P ("P" represents "parent" phase). We also observe these rearrangements of variants in the cooling processes under the magnetic field applied along [001] P , [011] P and [111] P by optical microscope. From the thermal expansion measurement and the optical microscope observation, the following results are are obtained: the variants are rearranged almost perfectly into the variants whose a axes are parallel to the magnetic field applied along [001] P , imperfectly into the variants whose c axis is perpendicular to the magnetic field applied along [011] P and hardly [111] P . We explain these results considering the following criterion: rearrangement of variants proceeds when a kind of shear stress generated by applying a magnetic field acting on the twinning plane is larger than the stress required for the rearrangement of variants.
  • Effect of Microstructure Evolution on Mechanical Property in Near-α Titanium Alloy during Aging
    Japanese Society of MicroscopyProceedings of The 16th International Microscopy Congress, 3,   2006年
  • Stability of B2-type structure and martensitic transformation in Ti-Ni shape memory alloys
    T. Fukuda, T. Sakamoto, T. Terai, T. Kakeshita, K. Kishio, Journal de Physique Ⅳ France, 112,   2003年10月01日, We have investigated electrical resistivity and magnetic susceptibility in a series of Ti-(50-x)Ni-xFe alloys, and observed their microstructure by electron microscopy, in order to know the phase stability of the B2-type structure. Following results were obtained: (i) The B2-R transformation temperature decreases as the iron content increases, and disappears in alloys with x ≥ 8. (ii) The alloy with x=8 shows a negative temperature coefficient in electrical resistivity and an inflection point in the temperature dependence of magnetic susceptibility curve, and these anomalies are suppressed as iron content increases and disappear completely in alloys with x ≥ 16. (iii) The electron diffraction of the alloy with x=8 shows 1/3 < 110 > diffuse scattering, and its intensity increases as temperature decreases. Furthermore, the dark field image obtained from the diffuse scattering show domain-like structure with its size smaller than 10nm. The results of (ii) and (iii) are related to the instability of the B2-type structure in Ti-Ni based alloys. As for such origin, the Fermi-surface-nesting of the B2-type structure with a vector q=1/3[110]2π/a is considered.
  • Microstructure Evolutions and Their Effects on Mechanical Properties in a Bainitic Steel
    Japanese Society of MicroscopyProceedings of The 16th International Microscopy Congress, 3,   2006年
  • Effects of S and Mn on Formations of Intragranular Bainite and Small-Angle Tilt-Boundary in Bainitic Steels
    Japanese Society of MicroscopyProceedings of The 16th International Microscopy Congress, 3,   2006年
  • Giant magnetic field-induced strain due to rearrangement of variants in an ordered Fe3Pt
    SAKAMOTO T, FUKUDA T, KAKESHITA T, TAKEUCHI T, KISHIO K, ElsevierScience and Technology of Advanced Materials, 5, (1/2) 35 - 40,   2004年01月01日, Magnetic field-induced strain due to rearrangement of martensite variants in a ferromagnetic Fe 3 Pt alloy single crystal with degree of order of about 0.8 has been investigated. The alloy exhibits a martensitic transformation from an ordered L1 2 -type structure to a tetragonal one at 85 K. The tetragonality of the martensite decreases as temperature decreases, and is about 0.945 at 14 K. When a magnetic field is applied along the [001] P direction ('P' stands for 'parent' phase) at 4.2 K after cooling down to the temperature under zero magnetic field, the specimen contracts more than 1% along this direction due to the rearrangement of variants. In association with this contraction, the fraction of the variant whose easy axis (c axis) is parallel to the [001] P direction reaches 70%. On the other hand, when the magnetic field is removed, a part of the strain initially induced by the magnetic field recovers and its value is 0.6% at 4.2 K. This recoverable strain repeatedly appears in the subsequent field applying and removing processes. The rearrangement of variants by a magnetic field is also confirmed by an X-ray measurement under the magnetic field. The energy dissipated due to the rearrangement of variants by the magnetic field is obtained from the magnetization curve to be about 180 kJ/m 3 . Based on these results and the magnetocrystalline anisotropy constant of the martensite phase (K u ≈500kJ/m 3 at 4.2 K), the mechanism of rearrangement of variants under the magnetic field is discussed. © 2003 Elsevier Ltd. All rights reserved.
  • Rearrangement of Martensite Variants in Iron-Based Ferromagnetic Shape Memory Alloys under Magnetic Field
    Takashi Fukuda, Tatsuaki Sakamoto, Tatsuaki Sakamoto, Tomoyuki Kakeshita, Tetsuya Takeuchi, Kohji Kishio, 日本金属学会, 45, (2) 188 - 192,   2004年02月01日, We have investigated magnetic field-induced strain (MFIS) associated with rearrangement of martensite variants and its corresponding magnetization process in a disordered Fe-31.2Pd(at%) single crystal and an ordered Fe 3 Pt single crystal, exhibiting a cubic to tetragonal martensitic transformation at 230 K and 85 K, respectively. When magnetic field is applied along [001] direction to a specimen with a multi-variant state, it expands along the field direction for Fe-31.2Pd and contracts for Fe 3 Pt, because the variants whose easy axis of magnetization (a axis for Fe-31.2Pd and c axis for Fe 3 Pt) lies along the field direction is selected to grow. The fraction of such variants reaches 100% for Fe-31.2Pd but does not for Fe 3 Pt. In the field removing process, a part of the MFIS recovers for Fe 3 Pt but does not for Fe-31.2Pd. From the magnetization curve, the energy dissipated due to the rearrangement of variants by magnetic field is obtained to be about 260 kJ/m 3 for Fe-31.2Pd and about 180 kJ/m 3 for Fe 3 Pt. Concerning Fe-31.2Pd, this value is roughly the same as that evaluated by stress-strain curves, suggesting that the rearrangement of variants by magnetic field takes essentially the same path as that by external stress. Based on these results and magnetocrystalline anisotropy constants of martensite phases, the mechanism of rearrangement of variants under magnetic field is discussed from a macroscopic point of view.
  • Effect of Microstructure Evolution on Mechanical Property in Metastable β Titanium Alloy during Aging
    Japanese Society of MicroscopyProceedings of The 16th International Microscopy Congress, 3,   2006年
  • Effects of Neutron Irradiation on the Microstructure in Pure W and Ultra-Fine Grained W-0.5TiC Alloys
    Japanese Society of MicroscopyProceedings of The 16th International Microscopy Congress, 3,   2006年
  • Magnetic Field-Induced Strain of Martensite and Parent Phases in a Ferromagnetic Shape Memory Iron-Palladium Alloy
    Tomoyuki Kǎkeshita, Takashi Fukuda, Tatsuaki Sakamoto, Trans Tech PublicationsMaterials Science Forum, 475-479,   2005年04月25日, We have investigated the magnetic field-induced strain (MFIS) of the martensite and the parent phases in an Fe-31.2Pd(at.%) single crystal, which exhibits a martensitic transformation at T M = 230K. Below T M , a large MFIS of several percent appears due to rearrangement of martensite variants and this strain remains when a magnetic field is removed. Such rearrangement depends on magnetic field direction; Variants are perfectly rearranged into the variant, which lowers the magnetocrystalline anisotropy energy most, when a magnetic field is applied along [001] P , and partially when [011] P and hardly when [111] P ("P" represents "parent" phase). The dependence on the field direction can be explained by comparing the magnetic shear stress τ mag with the shear stress τ req required for rearrangement of variants. Above the temperature, T M , a relatively large MFIS appears and it increases up to about 10 -3 with decreasing temperature from 280 K toward T M . This MFIS is probably caused by anomalies of some physical properties, such as elastic constant and dipole-dipole interaction coefficient in the parent phaser © 2005 Trans Tech Publications, Switzerland.
  • Rearrangement of Martensite Variants under Magnetic Field Applied along [001], [011] and [111] directions in Fe-31.2mol%Pd
    Tatsuaki Sakamoto, Tatsuaki Sakamoto, Takashi Fukuda, Tomoyuki Kakeshita, Kohji Kishio, IOS PressInternational Journal of Applied Electromagnetics and Mechanics, 21, (3-4) 163 - 169,   2005年08月11日, Rearrangement of variants of an Fe-31.2mol%Pd single crystal in the field-cooling process under the magnetic fields applied along [001] P , [011] P and [111] P (P: parent phase) has been investigated by strain measurement and optical microscope observation. The fraction of the variant, which lowers the magnetocrystalline anisotropy energy most, becomes almost 100% by the rearrangement of variants under the magnetic field applied along [001] P , but does not reach 100% under the magnetic field applied along [011] P . On the other hand, the rearrangement of variants hardly occurs under the magnetic field applied along [111] P . Influence of the field direction on rearrangement of variants described above can be evaluated quantitatively by using the magnetic shear stress τ mag and the shear stress required for rearrangement of variants τ req . © 2005 - IOS Press and the authors. All rights reserved.
  • Influence of Magnetic Field Direction and Temperature on Rearrangement of Martensite Variants in Fe-31.2at.%Pd
    Tatsuaki Sakamoto, Takashi Fukuda, Tomoyuki Kakeshita, Materials Science Forum, 512,   2006年12月01日, We have measured temperature dependence of the uniaxial magnetocrystalline anisotropy constant K u and the shear stress τ req , required for the twinning plane movement of an Fe-31.2Pd alloy in order to explain the field orientation dependence of rearrangement of martensite variants (RMV) of this alloy in the field-cooling process. Under the [001] P field (P represents parent phase), the RMV occurs perfectly at the temperatures where the measurement was performed; in this case, the magnetic shear stress acting across the twinning plane τ mag , which is evaluated from K u , becomes nearly twice as large as τ req . On the other hand, under the [011] p field, the RMV occurs partially at all the measuring temperatures; in this case the maximum of τ mag is nearly the same as τ req . It is successful to evaluate the following relation quantitatively; τ mag > τ req is satisfied when RMV occurs under magnetic field.
  • Magnetic domain structure in the presence of very thin martensite plates: Electron holography study on a thin-foil Fe-31.2at.%Pd alloy
    MURAKAMI Y., SHINDO D., SAKAMOTO T., FUKUDA T., KAKESHITA T., Acta Materialia, 54, (5) 1233 - 1239,   2006年03月01日, The magnetic domain structure of a thin-foil Fe-31.2 at.%Pd alloy, wherein the thickness of the martensite plates (of the order of 10 nm) is comparable to that of the magnetic domain walls, has been studied by electron holography and Lorentz microscopy. Magnetic flux maps obtained by electron holography demonstrate that the magnetization vectors are not necessarily oriented along the easy magnetization axis of the martensite - the result is in sharp contrast to the case of thick martensite plates (of the order of 10 2 nm or larger). This observation provides important information for actuator applications that utilize thin-foil ferromagnetic shape memory alloys. The change in the magnetic domain structure with the face-centered cubic to face-centered tetragonal martensitic transformation is also discussed. © 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
  • Influence of Temperature on Rearrangement of Martensite Variants by Magnetic Field in Fe3Pt
    T. Sakamoto, T. Fukuda, T. Kakeshita, ElsevierMaterials Science and Engineering A, 438-440,   2006年11月25日, We have investigated influence of temperature on magnetic field-induced strain due to rearrangement of martensite variants in Fe 3 Pt with a degree of order of 0.8. Measurements were made in the field-cooling process (FC) and field application process after zero-field cooling (ZFC), where magnetic field was applied along three principal directions: [0 0 1] P , [1 1 0] P and [1 1 1] P (index are given by the parent phase). From the measured strain and lattice parameters, we evaluated the fraction f P of the preferable variant, which has the lowest magnetic energy among three variants. In the case of the [0 0 1] P and [1 1 0] P fields, the fraction f P obtained by FC process (3.2 MA/m) gradually increase with decreasing temperature while f P obtained by field application process after ZFC shows a maximum value around 40 K. On the other hand, the field-induced strain does not appear for the [1 1 1] P field regardless of both processes. A part of the magnetic field-induced strain is reversible and it shows a maximum value of 1% at 20 K under the [0 0 1] P field. © 2006 Elsevier B.V. All rights reserved.
  • Effects of Transformation Stress and Deformation before Austenitization on Nucleation of Intragranular Bainite
    Kiyomichi Nakai, Norihiro Kanno, Ryo Asakura, Tatsuaki Sakamoto, Sengo Kobayashi, Masahiko Hamada, Yu Ichi Komizo, Trans Tech PublicationsMaterials Science Forum, 561 - 565,   2007年12月01日, Intragranular bainite is known to be effective to develop toughness greatly in steels. Effects of aging below eutectoid temperature before austenitization, the deformation before solution treatment and the duration of solution treatment on nucleation of intragranular bainite have been examined. In the austenite (γ) region where carbide pre-existed, the stress due to inverse transformation, ferrite (α) to γ, would be introduced into fine austenitized region with lower transus temperature to γ, resulting in the introduction of stable small-angle boundary at high temperatures acting as the nucleation site for intragranular bainite lath. Deformation of a by cold rolling before solution treatment enhances the nucleation of intragranular bainite, suggesting that the above γ region through the inverse transformation is easily deformed by the hardened neighboring α. In the deformed γ region, small-angle boundary would be more easily introduced, acting as nucleation site for intragranular bainite. Intragranular bainite lath grew and hardness decreased by prolonging the duration of solution treatment, indicating that transformation stress introduced by the pre-treatment was influenced by solution treatment. The effect of sulfur addition on formation of intragranular bainite was also analyzed.
  • Mechanical Alloying Process of Vanadium Powder with 1.7wt%Y Addition
    Kiyomichi Nakai, Sengo Kobayashi, Makoto Hidaka, Tatsuaki Sakamoto, Hiroaki Kurishita, ElsevierJournal of Nuclear Materials, 386 - 388,   2009年04月30日, Alloying process of vanadium-yttrium powders using mechanical alloying (MA) method was studied. Vanadium powder was compressed after 10 h MA, while yttrium powder was comminuted into small particles. Although yttrium powder was broken into small particles, yttrium scarcely dissolves into vanadium powder. Alloying of yttrium started after 20 h MA and finished after 40 h MA. Molybdenum particle, which came from milling vessels and balls, mixed into vanadium powder after 40 h MA and molybdenum started to dissolve into vanadium powder after 60 h MA. After 80 h MA, Y 2 O 3 particles formed in vanadium powder. Oxygen required for the formation of Y 2 O 3 particles was probably discharged from the vessel wall and balls after flaking of those surface layers. Since prolonged MA caused powder contamination, optimum MA time for making V-1.7Y alloy was 40 h. © 2009 Elsevier B.V. All rights reserved.
  • High Temperature Deformation of V-1.6Y-8.5W-(0.08-0.15)C Alloys
    Tatsuaki Sakamoto, Hiroaki Kurishita, Sengo Kobayashi, Kiyomichi Nakai, ElsevierJournal of Nuclear Materials, 386 - 388,   2009年04月30日, In order to improve the high temperature strength of fine-grained and particle-dispersed V alloys, V-1.6Y-8.5W-0.08C and V-1.6Y-8.5W-0.15C (wt%) were fabricated by mechanical alloying and hot isostatic pressing, followed by annealing at 1000 and 1200 °C for 3.6 ks. Dispersoids of Y 2 O 3 , V 2 C, WC and W 2 C are detected by X-ray diffraction in the 1000 and 1200 °C-annealed specimens. Tungsten dissolves in the V matrix after annealing at 1200 °C. Tensile tests were performed at temperatures from 800 to 1100 °C at initial strain rates from 1.0 × 10 -4 to 1.0 × 10 -2 s -1 . The yield stress at 900 °C of 1200 °C-annealed V-1.6Y-8.5W-0.15C is approximately 2 times as high as that of V-4Cr-4Ti, due to combination of solution hardening by W and dispersion hardening by the dispersoids. The obtained stress exponent of plastic strain rate and activation energy for deformation suggest that the deformation of V-1.6Y-8.5W-0.08C and V-1.6Y-8.5W-0.15C is controlled by solute atmosphere dragging. © 2009 Elsevier B.V. All rights reserved.
  • Crystallographic Orientation Dependence of Magnetic Field-Induced Strain in an Fe-31.2at.%Pd Alloy
    日本MRS, 28, (2) 247 - 248,   2003年
  • Local Atomic Structures of Amorphous Nd4.5Fe77B18.5 Alloys Formed under Different Cooling Rates and Their Relations to the Structures in the Early Stage of Crystallization
    日本金属学会, 44, (10) 2042 - 2047,   2003年
  • Rearrangement of Martensite Variants of Fe-31.2at.%Pd under Magnetic Field
    日本MRS, 29, (7) 3057 - 3058,   2004年
  • A model for nucleation of tin whisker through dislocation behavior
    K. Nakai, T. Sakamoto, S. Kobayashi, M. Takamizawa, K. Murakami, M. Hino, J. Phys. Conf. Ser., 165,   2009年07月27日, A model for the nucleation and growth processes of Sn whisker is offered. High density of localized screw dislocations by deformation form the dense spiral steps of atomic scale on Sn surface. The spiral steps would induce the nucleation of Sn whisker. Edge dislocations localized at the same region where dense screw dislocations exist supply Sn atoms to the Sn whisker through pipe diffusion. Both screw and edge dislocations would bend along almost one direction, namely, to relax the external shear stress. The image force also helps to bend the dislocations perpendicular to the whisker side-surface. The bending of dislocations at root of whisker leads the bend of whisker. The pipe diffusion of Sn atoms through edge dislocations from bulk Sn toward whisker is suppressed at the bent part of edge dislocation, resulting in release of Sn atoms inside whisker and leading to the growth of whisker near its root. © 2009 IOP Publishing Ltd.
  • Influence of Magnetic Field Direction on Recoverable Strain Due to Rearrangement of Variants in Fe3Pt
    日本MRS, 29, (7) 3059 - 3060,   2004年
  • 研究の世界に触れて
    阪本 辰顕, まてりあ, 45,   2006年01月20日
  • A model for nucleation and growth processes of tin whisker
    Kiyomichi Nakai, Tatsuaki Sakamoto, Sengo Kobayashi, Kazuto Arakawa, Hirotaro Mori, Masao Takamizawa, Koji Murakami, Makoto Hino, Mater. Sci. Forum, 638-642,   2010年02月09日, A model for the nucleation and growth processes of Sn whisker is offered. High density of localized screw dislocations by deformation form the dense spiral steps of atomic scale on Sn surface. The spiral steps would induce the nucleation of Sn whisker. Edge dislocations localized at the same region where the dense screw dislocations exist supply Sn atoms to Sn whisker through pipe diffusion. Both screw and edge dislocations would bend along almost one direction, namely, to relax the external shear stress. The image force also helps to bend the dislocations perpendicular to the whisker side-surface. The bending of dislocations at root of whisker leads the bend of whisker. The pipe diffusion of Sn atoms through edge dislocations from bulk Sn toward whisker is suppressed at the bent part of edge dislocation, resulting in release of Sn atoms inside whisker and leading to the growth of whisker near its root. © (2010) Trans Tech Publications.
  • Ti 基合金LCB の高強度化へ向けての微細組織制御
    阪本 辰顕, 前田 宗裕, 小林 千悟, 仲井 清眞, 社団法人日本金属学会まてりあ, 44,   2005年12月20日
  • Effect of quenching and reheating on isothermal phase transformation in Ti-15Nb-10Zr alloy
    Sengo Kobayashi, Ryoichi Ohshima, Kiyomichi Nakai, Tatsuaki Sakamoto, Mater. Sci. Forum, 638-642,   2010年02月09日, Isothermal phase transformation in Ti-15Nb-10Zr (at%) alloys has been examined by mainly means of transmission electron microscopy. Specimens solution-treated at 1000°C in β phase field were directly held at temperatures between 350 and 450°C for 1.8-86.4ks, which are called "DH (direct holding)-specimen". On the other hand, some specimens solution-treated at 1000° C were quenched into iced brine and then aged at temperatures between 350 and 450°C, which are called "QA(quench and aging)-specimen". In the DH-specimen held at 400°C ω phase formed in â matrix. Microstructure evolution of QA-specimen aged at 400°C, on the other hand, is as follows. ω phase formed in β matrix after aging for 1.8ks and further aging led to growth of ω phase. After prolonged aging, α phase started to form in β matrix. These experimental results indicate that process of the quenching and reheating promotes the formation of ω phase. Specimen quenched into iced brine after solution treatment exhibited α'' phase formation. The α'' phase in the quenched specimen would transform into β phase during reheating to the aging temperature. Reversion process of α'' → β phase could promote the formation of w phase in β. Microstructure formation in the DH- and QA-specimens at 350 and 450°C will also be explained. © (2010) Trans Tech Publications.
  • 強磁性形状記憶合金Fe-31.2mol%Pdの一軸磁気異方性定数ならびに双晶変形応力
    日本金属学会日本金属学会誌, 69, (8) 649 - 653,   2005年
  • ベイナイトの結晶学的組織制御と機械的性質
    大久保 宏記, 阪本 辰顕, 小林 千悟, 仲井 清眞, 濱田 昌彦, 小溝 裕一, 社団法人日本金属学会まてりあ, 44,   2005年12月20日
  • Magnetization Process Associated with Rearrangement of Martensite Variants in Iron-Based Ferromagnetic Shape Memory Alloys
    Materials Research SocietyMaterials Research Society Symposium Proceedings, Materials and Devices for Smart Systems, 785,   2004年
  • Nucleation of bainite at small angle dislocation network in austenite and its effects on mechanical properties in steels
    NAKAI Kiyomichi, SAKAMOTO Tatsuaki, ASAKURA Ryo, KOTANI Yuki, ISOMURA Noriyo, KOBAYASHI Sengo, HAMADA Masahiko, KOMIZO Yu−ichi, ISIJ International, 51, (2) 274 - 279,   2011年07月11日, Bainite lath nucleated WithIN Grain (BWING) has been clarified to be greatly effective for the increase in both strength and toughness. The nucleation of BWING has been enhanced by the introduction of inclusion into austenite, which would act as nucleation site for BWING. However, the inclusion itself would be brittle and at the interface between inclusion and matrix, high density of dislocations are apt to be accumulated under deformation, inducing cleavage at the interface. As density of inclusion increases, steel would be strengthened, but brittle. Therefore, the introduction of dislocation network, that is, Small-Angle Dislocation Network (SADN) into austenite is tried in the present work. SADN would be stable in the high temperature region such as in austenite, because pinned dislocation existed in SADN would prevent the bow-out of dislocations through absorbing point defects. The formation of SADN in austenite, which act as nucleation site for BWING, was clarified experimentally. The bainite lath neighbor to the nucleated one might be formed under relaxing the stress field around the nucleated one and/or inclusion. It was analyzed that the average size of Aggregates of bainite Laths having nearly Parallel Slip systems between neighboring bainite laths (ALPS) corresponds to that of dimples on fracture surface. The process for ductile fracture is offered based on the crystallographic analysis using transmission electron microscopy. © 2011 ISIJ.
  • High Temperature Tensile Properties and Their Application to Ductility Enhancement in Ultra-Fine Grained W-(0-15)wt%TiC
    ElsevierJournal of Nuclear Materials, 386 - 388,   2009年
  • Effect of Nb Addition on Cu Precipitation in Ferritic Stainless Steel
    Sengo Kobayashi, Takafumi Takeda, Kiyomichi Nakai, Jun Ichi Hamada, Norihiro Kanno, Tatsuaki Sakamoto, ISIJ International, 51, (4) 657 - 662,   2011年08月08日, Formations of Cu-rich precipitate in 18%Cr-1.5%Cu stainless steels without and with 0.5%Nb have been examined mainly using transmission electron microscopy. The specimens solution-treated at 1250°C were isothermally transformed at various temperatures between 500 and 850°C. Fine spherical Cu-rich solute zones were nucleated in the steels in the beginning of aging. These Cu-rich zones exhibited bcc structure and then transformed into 9R structure with twins during aging. The spherical 9R-Cu particles changed into rod-shaped fcc-Cu particles after prolonged aging. Laves phase of Fe 2 Nb type started to form in the Nb-added steel almost after finishing nucleation and growth of Cu particles. Addition of Nb in the steel delayed the nucleation of the Cu-rich zones due to slow diffusion of Nb atoms in ferrite. © 2011 ISIJ.
  • Variation of hardness with microstructure evolutions in metastable β titanium alloy TIMETAL® LCB
    Trans Tech PublicationsMaterials Science Forum, 561 - 565,   2007年
  • Effect of microstructural evolutions on hardness in a metastable β Ti alloy
    The Japan Institute of MetalsProceedings of the 11th World Conference on Titanium (JIMIC5), Ti - 2007 Science and Technology,   2007年
  • EFFECTS OF SMALL-ANGLE BOUNDARY ON NUCLEATION OF INTRAGRANULAR BAINITE IN BAINITIC STEELS
    Proceedings of The Second International Symposium on Smart Processing Thechnology(SPT’07), 2,   2008年
  • EFFECTS OF OXIDES ON NUCLEATION OF INTRAGRANULAR BAINITE IN HEAT AFFECTED ZONE IN STEELS
    Proceedings of The Second International Symposium on Smart Processing Thechnology(SPT’07), 2,   2008年
  • Precipitation Behavior in a Low Cost Beta Titanium Alloy During Aging
    Journal of the Japan Society for Heat Treatment, 49,   2009年
  • Effects of small-angle boundary on nucleation of intragranular bainite in steels
    J. the Japan Society for Heat Treatment, 49,   2009年
  • Effects of Bs on the evolution of intragranular bainite in steel welds
    J. the Japan Society for Heat Treatment, 49,   2009年
  • Effects of cooling rate and Zr addition on microstructure formation in Ti - (15, 20) at% Nb alloys
    J. the Japan Society for Heat Treatment, 49,   2009年
  • Precipitation of β' phase in a low cost beta titanium alloy
    Mater. Sci. Forum, 638-642,   2010年
  • Recovery Processes of Cascade Damage by Neutron Irradiation in V-1.6Y Alloy
    J. Nuclear Materials, submitted,   2010年
  • Microstructural Analyses of B4C-CeO2 and B4C-La2O3 Ceramics
    J. Nuclear Materials, submitted,   2010年
  • Markedly refined W-TiC exhibiting low DBTT and high radiation durability
    J. Nuclear Materials, submitted,   2010年
  • Effects of plastic working and MA atmosphere on microstructures in W-(1.0-1.1)%TiC
    J. Nuclear Materials, submitted,   2010年
  • Effects of Grain Size on High Temperature Creep of Fine Grained, Solution and Dispersion Hardened V-1.6Y-8W-0.8TiC
    J. Nuclear Materials, submitted,   2010年
  • Effect of microstructure on hardness in metastable β titanium alloy
    Annual J. Engineering, Ehime University, 7,   2008年

書籍等出版物

講演・口頭発表等

  • フェライト鋼中のCu析出・粗大化挙動に及ぼすCr添加効果
    山中 大輔, 小林 千悟, 濱田 純一,神野 憲博,阪本 辰顕, 日本鉄鋼協会 第171 回春季講演大会,   2016年03月23日
  • ナノ組織を有する粒子分散Al合金の高温強度に及ぼす希土類元素の効果
    阪本 辰顕, アルミニウム研究助成成果報告会,   2016年03月14日
  • Ti‐NbおよびTi‐Mo合金の内部構造とヤング率の相関関係
    中尾ありさ, 小林千悟, 阪本辰顕, 日本金属学会講演概要(CD-ROM),   2016年03月09日
  • Si含有ニアαチタン合金の高温変形に及ぼす初期組織の影響
    阪本辰顕, 松村裕, 小林千悟, 日本金属学会講演概要(CD-ROM),   2016年03月09日
  • Ti‐2at%Mo合金のスピノーダル分解挙動ならびに機械的特性に及ぼす酸素の影響
    宮本裕太, 小林千悟, 阪本辰顕, 日本金属学会講演概要(CD-ROM),   2016年03月09日
  • メカニカルアロイング法による多元系合金分散銅合金の作製
    津崎卓也, 阪本辰顕, 小林千悟, 日本金属学会講演概要(CD-ROM),   2016年03月09日
  • ベイナイト鋼における粒内ベイナイト・ラス集合状況と引張破面の対応関係
    阪本 辰顕, 吉澤 俊希 , 第3回愛媛大学先進超高圧科学研究拠点(PRIUS)シンポジウム,   2016年02月23日
  • Composition Dependence on Microstructure and Mechanical Properties in Quenched Ti-(Mo, Nb, Fe) Alloys
    Sengo Kobayashi, Keisuke Manabe, Arisa Nakao, Masato Ueda, Masahiko Ikeda and Tatsuaki Sakamoto, Twenty-Fourth International Symposium on Processing and Fabrication of Advanced Materials (PFAM XXIV),   2015年12月20日
  • Effect of Al Addition on the Microstructure Formation in Quenched Ti-Mo and Ti-Nb Alloys
    Hiroaki Sogame, Sengo Kobayashi and Tatsuaki Sakamoto, Twenty-Fourth International Symposium on Processing and Fabrication of Advanced Materials (PFAM XXIV) ,   2015年12月19日
  • Adhesion and Spreading of MC3T3 - E1 Osteoblast - like Cells on Various Metals and Their Oxides
    Y. Yamauchi, S. Kobayashi, S. Okano, K. Kuroda, T. Okamoto, T. Sakamoto, International Symposium on EcoTopia Science 2015, ISETS '15 ,   2015年11月28日
  • Effect of neutron irradiation on mechanical property in V-1.4Y-7W-9Mo-0.7TiC
    阪本 辰顕, 大洗研究会,   2015年10月22日
  • Ti‐Nb合金の微細組織ならびに機械的特性に及ぼすFe添加効果
    中尾ありさ, 小林千悟, 阪本辰顕, 日本金属学会 2015年秋期講演大会(第157回) ,   2015年09月02日
  • Ti合金の焼入れ組織ならびに機械的特性に及ぼすβ相安定化元素の効果
    真鍋慶祐, 小林千悟, 阪本辰顕, 日本金属学会 2015年秋期講演大会(第157回) ,   2015年09月02日
  • Si含有ニアαチタン合金の時効挙動に及ぼす初期組織の影響
    阪本辰顕, 秋山博彰, 秋山博彰, 松村裕, 小林千悟, 日本金属学会 2015年秋期講演大会(第157回) ,   2015年09月02日
  • ベイナイト鋼における逆変態γ内の転位網生成に及ぼす冷間圧延の効果とその機械的性質への影響
    小西早苗, 仲井清眞, 阪本辰顕, 小林千悟, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • 種々の温度におけるフェライト鋼中のCu析出挙動に及ぼすCr添加効果
    山中大輔, 小林千悟, 阪本辰顕, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • ベイナイト鋼における粒内ベイナイト・ラス集合状況と引張破面の対応関係
    吉澤俊希, 仲井清眞, 小林千悟, 阪本辰顕, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • ベイナイト鋼における逆変態γ中に導入される転位網のBWING・ALPS生成ならびに機械的性質に及ぼす効果
    小西早苗, 仲井清眞, 阪本辰顕, 小林千悟, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • 鉄鋼材料におけるオーステナイト中への転位網の導入とその存在の確認
    平本貴史, 仲井清眞, 阪本辰顕, 小林千悟, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • オーステナイト化前処理としてのパーライト生成がベイナイト鋼の機械的性質に及ぼす効果
    仲井清眞, 中西祐太, 阪本辰顕, 小林千悟, 日本鉄鋼協会 第170 回秋季講演大会,   2015年09月01日
  • AZ91マグネシウム鋳造合金の機械的性質に及ぼす構成相の効果
    阪本 辰顕, 世羅 和彦, Shuchen Sun, 小林 千悟, 日本鉄鋼協会第58回・日本金属学会第55回中国四国支部講演大会,   2015年08月19日
  • DV-Xα First Principle Analysis of the Effect of Alloying Elements on the α" Phase Formation in Ti Alloys
    Sengo Kobayashi, Riku Wakamoto, Tatsuaki Sakamoto, The 13th World Conference on Titanium 2015 ,   2015年08月18日, 招待有り
  • ニアαチタン合金Ti-1100の動的再結晶に及ぼすシリサイドの効果
    阪本 辰顕,大塚 尚平,松村 裕,小林 千悟, 第7回 軽金属学会 中国四国支部 講演大会,   2015年07月04日
  • Ti-3at%Mo合金に及ぼす2段時効処理の効果
    福島 崚平, 小林 千悟, 阪本 辰顕, 第7回 軽金属学会 中国四国支部 講演大会,   2015年07月04日
  • Antimicrobial and Bioactive Anodized Film on Ti-Ag Alloy
    S. Kobayashi, Y. Sato, T. Kikuchi, S. Okano, T. Sakamoto, Biomaterials International 2015,   2015年06月04日
  • Ti‐Nb,Ti‐Mo合金の微細組織ならびに機械的特性に及ぼすFe添加効果
    中尾ありさ, 小林千悟, 宮本晃, 阪本辰顕, 軽金属学会 第128回春期大会,   2015年04月16日
  • Ti-8Nb合金の内部組織ならびにヤング率に及ぼすFe添加効果
    中尾 ありさ, 小林 千悟, 阪本 辰顕, 第7回 軽金属学会 中国四国支部 講演大会,   2015年07月04日

受賞

  •   2005年, 日本金属学会論文賞
  •   2005年, 日本鉄鋼協会 努力賞
  •   2005年, 日本金属学会 第4回優秀ポスター賞
  •   2006年, 日本金属学会 第5回優秀ポスター賞
  •   2007年, 日本鉄鋼協会中国四国支部 優秀学生賞
  •   2007年, 軽金属学会中国四国支部 奨励賞
  •   2008年, 日本金属学会中国四国支部 優秀学生賞
  •   2008年, 軽金属学会中国四国支部 奨励賞
  •   2008年, 日本金属学会 優秀ポスター賞
  •   2009年, (社) 日本金属学会 中国四国支部 優秀学生賞
  •   2009年, (社) 日本鉄鋼協会 中国四国支部 優秀学生賞
  •   2009年, (社) 日本鉄鋼協会 中国四国支部 優秀学生賞

競争的資金



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