KIMURA Yuuji

J-GLOBAL         Last updated: Mar 14, 2019 at 21:58
 
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Name
KIMURA Yuuji
Affiliation
National Institute for Materials Science
Section
Structural Metals Center
Job title
Chief Researcher
Degree
Doctor of Engineering

Research Areas

 
 

Academic & Professional Experience

 
1999
   
 
: Researcher, National Research Institute for Metals
 
1993
   
 
: Research Associate, Faculty of Engineering,
 
 
   
 
Kyushu University
 

Education

 
 
   
 
Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University
 
 
   
 
Kyushu University, Graduate School of Engineering
 

Awards & Honors

 
 
and Steel Institute of Japan (2000)
 
 
Sawamura Paper Award of the Iron
 

Misc

 
Kimura Yuuji, Inoue Tadanobu
Tetsu-to-Hagane      2019
<p>Our strategy to enhance fracture properties of ultra-high-strength low-alloy steel with a yield strength of 1.4 GPa or over is to arrest the propagation of brittle crack in a hierarchical, anisotropic and ultrafine grain structure designed to b...
井上忠信, 上路林太郎, 木村勇次
日本機械学会論文集(Web)   84(866) ROMBUNNO.18‐00237(J‐STAGE)   2018
INOUE Tadanobu, KIMURA Yuuji
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A   79(804) 1226-1238   Oct 2013
A low-carbon steel bar with an ultrafine elongated grain (UFEG) structure and an ultrafine exiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 500&deg;C and subsequent annealing at 500, 550, 600 and 650&deg;C. The Charpy i...
木村勇次, 井上忠信, 中田隆之, 福田又一
日本機械学会論文集(Web)   84(860) ROMBUNNO.17‐00493(J‐STAGE)   2018
NAGASHIMA Nobuo, FURUYA Yoshiyuki, INOUE Tadanobu
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A   78(790) 923-927   Jul 2012
Giga-cycle fatigue properties were investigated for an ultrafine-grained steel processed by warm tempforming. The fatigue properties of the tempformed (TF) steel were compared with conventional tempered martensite (QT) steel. Fatigue tests were ca...
INOUE Tadanobu, UEJI Rintarou, KIMURA Yuuji
Transactions of the JSME (in Japanese)      2018
<p>The relationship among strength, ductility, toughness and microstructure was studied in order to find out microstructure image of stronger and tougher steel. Initial samples with two different microstructures, ferrite-pearlite and martensite (a...
佐藤篤司, 鈴木宏彰, 木村勇次
鋼構造年次論文報告集(CD-ROM)   25 ROMBUNNO.23   Nov 2017
Yuuji Kimura, Tadanobu Inoue, Eiji Akiyama, Eiji Akiyama
Materials Science and Engineering A   703 503-512   Aug 2017
© 2017 Hydrogen embrittlement properties were investigated for 1.8-GPa-class ultra-high strength low-alloy steels by means of slow-strain-rate test of the pre-hydrogen-charged notched specimens, accelerated atmospheric corrosion test, and thermal ...
木村勇次, 澤口孝宏, 江村聡, 木村勇次, 澤口孝宏, 江村聡
金属   87(1) 5‐12   Jan 2017
井上忠信, 木村勇次
日本機械学会論文集(Web)   82(844) ROMBUNNO.16‐00246(J‐STAGE)   2016
Yuuji Kimura, Tadanobu Inoue
Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan   100(9) 1104-1113   Jan 2014
(0.2-0.6)%C-2%Si-1%Cr-1%Mo steels were quenched and tempered at 773 K and then deformed by multi-pass caliber rolling (i.e., warm tempforming) with a rolling reduction of 78 % to obtain ultrafine elongated grain (UFEG) structures. Tensile and Char...
井上忠信, 木村勇次, QIU Hai, WANG Chengduo, WANG Chengduo
日本機械学会論文集(Web)   81(830) 15-00281(J-STAGE)   2015
山口隆司, 長崎英二, 潘超, 木村勇次
土木学会論文集 A1(構造・地震工学)(Web)   70(3) 409-417 (J-STAGE)   2014
Chengduo Wang, Hai Qiu, Yuuji Kimura, Tadanobu Inoue
Materials Science and Engineering A   669 48-57   Jul 2016
© 2016 Elsevier B.V. The tempered lath martensite and its crack propagation have significant influence on the ductility and toughness of the warm tempformed medium-carbon steel. The martensitic microstructures of these medium-carbon steels are tra...
木村勇次, 井上忠信
熱処理   52(6) 299-300   Dec 2012
Yuuji Kimura, Tadanobu Inoue
ISIJ International   56 2047-2056   Jan 2016
© 2016 ISIJ. A 0.4C-2Cr-1Mo-2Ni steel (in mass%) was austenitized at 1 123 K, followed by ausforming (AF) using multi-pass caliber rolling with a rolling reduction of 74%. The AF samples were subsequently tempered at 773 K and deformed by multi-pa...
Xiaohua Min, Xiaohua Min, Yuuji Kimura, Takashi Kimura, Kaneaki Tsuzaki, Kaneaki Tsuzaki
Materials Science and Engineering A   649 135-145   Jan 2016
© 2015 Elsevier B.V. The effect of phosphorus (P) on delamination toughening was examined for 0.4%C-1%Cr-0.7%Mn-0.2%Mo steels (mass%) comprised of ultrafine elongated grain (UFEG) structures with strong <110>//rolling direction (RD) fiber textures...
INOUE Tadanobu, KIMURA Yuuji
Transactions of the JSME (in Japanese)   82(844) 16-00246-16-00246   2016
<p>The criterion of micro-crack initiation on stronger, tougher steel, i.e., fail-safe steel, with an ultrafine elongated grain (UFEG) structure was studied through a combinations of numerical simulation and experimental observations and measureme...
Yuuji Kimura, Tadanobu Inoue
ISIJ International   55 1135-1144   Jan 2015
© 2015 ISIJ. (0.2-0.6)%C-2%Si-1%Cr-1%Mo steels were quenched and tempered at 773 K and deformed by multipass caliber rolling (i.e. warm tempforming) with a rolling reduction of 78%, in order to obtain ultrafine elongated grain (UFEG) structures. T...
Yuuji Kimura, Tadanobu Inoue
ISIJ International   55 1762-1771   Jan 2015
© 2015 ISIJ. 0.4%C-2%Si-1%Cr-1%Mo steels with different austenite grain structures were quenched and tempered at 773 K and deformed by multi-pass caliber rolling with a rolling reduction of 78% (i.e. warm tempforming, (WTF)). The microstructures, ...
Yuuji Kimura
Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan   100 1181   Jan 2014
Yuuji Kimura, Tadanobu Inoue, Kaneaki Tsuzaki
Journal of Alloys and Compounds   577    Nov 2013
Deformation of tempered martensitic structure, i.e., tempforming using a caliber rolling at 500 C was applied to a 0.4%C-2%Si-1%Cr-1%Mo steel to obtain ultrafine elongated grain structure with a strong 〈1 1 0〉//RD fiber deformation texture and the...
Tadanobu Inoue, Yuuji Kimura
Journal of Materials Science   48 4766-4772   Jul 2013
A 0.4C-2Si-1Cr-1Mo steel bar with an ultrafine-elongated grain (UFEG) structures was produced by multi-pass warm caliber rolling. The test sample was machined from the rolled bar with 0, 45, and 90 rotation along the rolling direction, and a stati...
Eiji Akiyama, Maoqiu Wang, Maoqiu Wang, Songjie Li, Zuogui Zhang, Zuogui Zhang, Yuuji Kimura, Nobuyoshi Uno, Kaneaki Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   44 1290-1300   Mar 2013
Hydrogen embrittlement of high-strength steels was investigated by using slow strain rate test (SSRT) of circumferentially notched round bar specimens after hydrogen precharging. On top of that, cyclic corrosion tests (CCT) and outdoor exposure te...
Hideyuki Hidaka, Yuuji Kimura, Setsuo Takaki
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   46(12) 1256-1260   Jan 1999
The mechanically milled Fe-0.8mass%C alloy powder (MM powder) was packed in stainless steel tubes and hot-rolled to consolidate powder to the bulk material with full density (MM bulk material), and the mechanism during consolidation of the MM powd...
Meysam Jafari, Meysam Jafari, Yuuji Kimura, Kaneaki Tsuzaki, Kaneaki Tsuzaki
Philosophical Magazine Letters   93 109-115   Feb 2013
Phosphorus-doped high-strength steels are typically brittle at room temperature. In contrast to the non-hardening embrittlement of body-centred cubic (bcc) steels which decreases toughness without increasing strength, we observed an increase in to...
Yuuji Kimura, Tadanobu Inoue
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   44 560-576   Jan 2013
A 0.4 pct C-2 pct Si-1 pct Cr-1 pct Mo steel was quenched and tempered at 773 K (500 C) and deformed by multi-pass caliber rolling (i.e., warm tempforming). The microstructures and the mechanical properties of the warm tempformed steels were inves...
HIDAKA Hideyuki, KIMURA Yuuji, TAKAKI Setsuo
Tetsu- to- Hagane   85(1) 52-58   Jan 1999
Mechanical milling using high energy planetary ball mill was applied to Fe-C alloy powders with (ferrite+cementite) two-phase structures to give an ultimate large strain into the powders. Dissolution behavior of cementite during mechanical milling...
Meysam Jafari, Yuuji Kimura, Kaneaki Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   43 2453-2465   Jul 2012
An ultrafine elongated grain (UFEG) structure with strong (110)//rolling direction (RD) fiber deformation texture was produced by warm-caliber rolling at 773 K (500 °C) and final tempering at 823 K (550 °C), namely tempforming in the 1200 MPa-clas...
Tadanobu Inoue, Yuuji Kimura, Shojiro Ochiai
Science and Technology of Advanced Materials   13    Jun 2012
A 0.4C-2Si-1Cr-1Mo steel with an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 773K and subsequent annealing at 973K. A static three-point bending test was...
Yihong Nie, Yuuji Kimura, Tadanobu Inoue, Fuxing Yin, Eiji Akiyama, Kaneaki Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   43 1670-1687   May 2012
A deformation of a tempered martensitic structure (i.e., tempforming) at 773 K (500°C) was applied to a 0.6 pct C-2 pct Si-1 pct Cr steel. The hydrogen embrittlement (HE) property of the tempformed (TF) steel was investigated by a slow strain rate...
M. Jafari, M. Jafari, Y. Kimura, K. Tsuzaki, K. Tsuzaki
Materials Science and Engineering A   532 420-429   Jan 2012
The ultrafine elongated grain (UFEG) structure with strong <1. 1. 0>//RD fiber deformation texture was produced by warm caliber-rolling at 500°C and final tempering at 550°C, namely tempforming in the 1100. MPa medium carbon-low alloy steel with u...
Iaroslava Shakhova, Andrey Belyakov, Rustam Kaibyshev, Yuuji Kimura, Kaneaki Tsuzaki
Advanced Materials Research   409 607-612   Jan 2012
Tensile behaviour of two steels with submicrocrystalline structures, i.e. a 304-type austenitic steel and an Fe-27%Cr-9%Ni austenitic-ferritic steel, was studied. The starting materials were subjected to large strain rolling and swaging to a total...
Meysam Jafari, Meysam Jafari, Yuuji Kimura, Kaneaki Tsuzaki, Kaneaki Tsuzaki
Advanced Materials Research   409 231-236   Jan 2012
Ultrafine elongated grain (UFEG) structures with strong 〈110〉// rolling direction (RD) fiber deformation texture were produced by warm caliber-rolling at 773 K, namely tempforming in the 1200 MPa-class medium-carbon low-alloy steel with phosphorou...
高木節雄, 木村勇次
まてりあ   34(8) 959-963   Aug 1995
Kimura Yuuji, Takaki Setsuo, Goto Hideto
Journal of the Japan Institute of Metals and Materials   59(12) 1278-1285   Jan 1995
Fe-Cu super-saturated solid solution powders were prepared by mechanical alloying of the elemental Fe and Cu powders, and the sintering behavior of the mechanically alloyed powders was investigated in association with the separation behavior of th...
Li Songjie, Akiyama Eiji, Yuuji Kimura, Tsuzaki Kaneaki, Uno Nobuyoshi, Zhang Boping
SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS   11(2)    Apr 2010   [Refereed]
木村勇次, 井上忠信, 殷福星, 津崎兼彰
工業材料   58(1) 46-47   Jan 2010
木村勇次
ふぇらむ   14(3) 154-161   Mar 2009
木村勇次
プレス技術   46(13) 71-75   Nov 2008
山口隆司, 増田浩志, 木村勇次
鋼構造論文集   15(59) 99-107   Sep 2008
木村勇次
型技術   23(10) 057-061   Sep 2008
木村勇次, 秋山英二, 津崎兼彰
鋼構造論文集   14(54) 121-127   Jun 2007
広田憲亮, 井上忠信, 木村勇次, 東司, 長井寿
熱処理   46(4) 214-220   Aug 2006
井上忠信, YIN Fuxing, 木村勇次, 長井寿
日本金属学会誌   69(11) 943-952   Nov 2005
津崎兼彰, 木村勇次
鉄鋼の析出制御メタラジー最前線2 析出制御メタラジー研究会最終報告書 平成15年   56-57   2003
沢井達明, 木村勇次, 津崎兼彰, 竹内悦男, 松岡三郎
日本機械学会論文集 A編   68(665) 49-56   Jan 2002
木村勇次, 高木節雄
塑性と加工   41(468) 13-17   Jan 2000
Yuuji Kimura, Yuuji Kimura, Hideyuki Hidaka, Hideyuki Hidaka, Setsuo Takaki
Materials Transactions, JIM   40 1149-1157   Jan 1999
Mechanical milling using a high energy ball mill was applied to a commercial pure iron powder to introduce a large deformation strain into the matrix. Microstructural changes during deformation and annealing were investigated for the mechanically ...
木村 勇次, 井上 忠信
ふぇらむ = Bulletin of the Iron and Steel Institute of Japan : (一社)日本鉄鋼協会会報   17(12) 829-835   2012
Tadanobu Inoue, Yuuji Kimura, Shojiro Ochiai
Scripta Materialia   65 552-555   Sep 2011
A 1800 MPa class steel with ultrafine elongated grain structures was fabricated by multi-pass caliber rolling and a static three-point bending test was conducted. The strength-toughness balance of the developed steel was remarkably improved compar...
Meysam Jafari, Meysam Jafari, Yuuji Kimura, Yihong Nie, Kaneaki Tsuzaki, Kaneaki Tsuzaki
ISIJ International   50 1660-1665   Dec 2010
An ultrafine elongated grain (UFEG) structure with a strong 〈110〉//rolling direction (RD) fibre deformation texture was produced by warm calibre-rolling at 773 K in 1 200MPa-class medium-carbon low-alloy steels with phosphorous (P) contents of 0.0...
Yuuji Kimura, Tadanobu Inoue, Y. I N Fuxing, Y. I N Fuxing, Kaneaki Tsuzaki
ISIJ International   50 152-161   Mar 2010
The deformation of tempered martensitic structures, namely tempforming treatments, were applied to a 0.6C-2Si-1Cr steel at 500, 600 and 700°C using multi-pass caliber-rolling with an accumulated area reduction of 80%. The tensile and Charpy impact...
Tadanobu Inoue, Fuxing Yin, Yuuji Kimura
Materials Science Forum   638-642 2793-2798   Feb 2010
The evolution of crystallographic texture with equivalent strain, εeq, was studied in low carbon steel bars fabricated using multi-pass warm caliber rolling. Finite element analysis was carried out to evaluate εeq accumulated and strain components...
Andrey Belyakov, Rustam Kaibyshev, Yuuji Kimura, Kaneaki Tsuzaki
Materials Science Forum   638-642 1905-1910   Feb 2010
The structural recrystallization mechanisms operating in an Fe - 27%Cr - 9% Ni dual-phase (ferrite-austenite) stainless steel after large strain processing to total strain of 4.4 were investigated in the temperature range of 400-700°C. The severe ...
Tadanobu Inoue, Fuxing Yin, Yuuji Kimura, Kaneaki Tsuzaki, Shojiro Ochiai
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   41 341-355   Feb 2010
Bulk ultrafine-grained (UFG) low-carbon steel bars were produced by caliber rolling, and the impact and tensile properties were investigated. Initial samples with two different microstructures, ferrite-pearlite and martensite (or bainite), were pr...
高木節雄, 木村勇次
材料技術   15(3) 69-73   Apr 1997
高木節雄, 木村勇次
トランプエレメントの鉄鋼材料科学 スクラップ起因不純物元素との上手なつき合い方 平成9年   53-60   1997
KIMURA Yuuji
Bulletin of the Iron and Steel Institute of Japan   14(3) 154-161   Mar 2009
Andrey Belyakov, Kaneaki Tsuzaki, Kaneaki Tsuzaki, Yuuji Kimura
ISIJ International   48 1071-1079   Nov 2008
The recent studies on grain refinement in several Cr-Ni ferritic stainless steels during large strain deformation at room temperature are critically reviewed. The paper is focussed on the mechanism of structural changes that is responsible for ult...
Yuuji Kimura, Tadanobu Inoue, Fuxing Yin, Kaneaki Tsuzaki
Science   320(5879) 1057-1060   May 2008
Materials are typically ductile at higher temperatures and become brittle at lower temperatures. In contrast to the typical ductile-to-brittle transition behavior of body-centered cubic (bcc) steels, we observed an inverse temperature dependence o...
Yuuji Kimura, Tadanobu Inoue, Fuxing Yin, Kaneaki Tsuzaki
Proceedings of the 17th IFHTSE Congress   2 430-433   Jan 2008
Innovative Materials Engineering Laboratory, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan The deformation of a tempered martensitic structure, namely tempforming was applied to a high purity 0.4%C-2%Si-l...
T. Inoue, F. Yin, Y. Kimura
Materials Science and Engineering A   466 114-122   Sep 2007
The three-dimensional finite element-analysis and electron backscattered diffraction analysis are used to study quantitative correlation between effective strain and deformed microstructure in low carbon steel bars fabricated through multi-pass wa...
Y. Kimura, T. Inoue, F. Yin, O. Sitdikov, K. Tsuzaki
Scripta Materialia   57 465-468   Sep 2007
A deformation of tempered martensite, namely tempforming at an elevated temperature, was applied to a medium-carbon low-alloy steel. This thermomechanical treatment led to an evolution of an ultrafine fibrous grain structure with a strong 〈1 1 0〉∥...
Tadanobu Inoue, Fuxing Yin, Yuuji Kimura
Materials Transactions   48 2028-2035   Aug 2007
The evolution of crystallographic texture with effective strain up to 5.9 is studied in low carbon steel bars fabricated using multi-pass warm caliber rolling. Three-dimensional finite element analysis was carried out to evaluate distributions of ...
Andrey Belyakov, Kaneaki Tsuzaki, Kaneaki Tsuzaki, Yuuji Kimura, Yoshisato Kimura, Yoshinao Mishima
Materials Science and Engineering A   456 323-331   May 2007
Deformation microstructures of an Fe-15%Cr ferritic stainless steel during cold working to strains above 7 were studied. Two processing methods, unidirectional working consisting of bar rolling followed by swaging and multidirectional working invo...
O. Sitdikov, O. Sitdikov, T. Sakai, E. Avtokratova, R. Kaibyshev, Y. Kimura, K. Tsuzaki
Materials Science and Engineering A   444 18-30   Jan 2007
Grain refinement taking place during equal-channel angular pressing (ECAP) was studied in a commercial Al-6% Mg-0.4% Mn-0.3% Sc alloy at a temperature of 450 °C (∼0.8Tm) to demonstrate the feasibility of obtaining new fine-grained structure in a h...
Kaneaki Tsuzaki, Andrey Belyakov, Andrey Belyakov, Yuuji Kimura
Materials Science Forum   503-504 305-310   Dec 2006
Deformation microstractures were studied in a two-phase (about 60% ferrite and 40% austenite) Fe - 27%Cr - 9%Ni stainless steel. Severe plastic working was carried out by rolling from 21.3×21.3 mm2to 7.8×7.8 mm2square bar followed by swaging from ...
Andrey Belyakov, Andrey Belyakov, Yuuji Kimura, Kaneaki Tsuzaki
Materials Science Forum   503-504 323-328   Dec 2006
The annealing behaviour of an Fe - 22%Cr - 3%Ni ferritic stainless steel processed by bar rolling/swaging to total strain of 4.4 at an ambient temperature was studied in the temperature range of 400-700°C. The annealing behaviour was characterised...
HIROTA Noriaki, INOUE Tadanobu, KIMURA Yuji, AZUMA Tsukasa, NAGAI Kotobu
熱処理 = Journal of The Japan Society for Heat Treatment   46(4) 214-220   Aug 2006
A. Belyakov, Y. Kimura, K. Tsuzaki
Acta Materialia   54 2521-2532   May 2006
Deformation microstructures of an Fe-27% Cr-9% Ni dual-phase stainless steel, which was bar rolled/swaged to a total strain of 6.9 at ambient temperature, were studied. After a rapid increase in the hardness during early deformation, the rate of s...
INOUE Tadanobu, YIN Fuxing, KIMURA Yuji, NAGAI Kotobu
Journal of the Japan Institute of Metals and Materials   69(11) 943-952   Nov 2005
&nbsp;&nbsp;Ultrafine-grained bars of a low carbon steel with a cross section of 12.9 mm and 7.9 mm square are fabricated through a multi-pass groove rolling at 773 K. A three-dimensional explicit finite element analysis is employed to evaluate in...
Andrey Belyakov, Andrey Belyakov, Y. Kimura, K. Tsuzaki
Materials Science and Engineering A   403 249-259   Aug 2005
Recovery and recrystallization were studied in a Fe-22% Cr-3% Ni ferritic stainless steel processed by bar rolling/swaging at an ambient temperature. The annealing behaviour significantly depended on the preceding cold strain. The samples processe...
A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Materials Science Forum   467-470 229-234   Dec 2004
Several Fe - O samples containing different fractions of dispersed oxides were processed by mechanical milling followed by consolidating rolling. The samples were annealed at 1000°C and then compressed to strains of 0.35, 1.2, and 1.9 at an ambien...
Andrey Belyakov, Yoshikazu Sakai, Toru Hara, Yuuji Kimura, Kaneaki Tsuzaki
Materials Transactions   45 2252-2258   Jan 2004
The annealing behaviour of ultrafine grained steels containing nano-scale dispersed oxides was studied in a temperature range of 600-900°C by means of microstructural observations and hardness measurement. The starting materials with submicrocryst...
Andrey Belyakov, Andrey Belyakov, Yuuji Kimura, Yoshitaka Adachi, Kaneaki Tsuzaki
Materials Transactions   45 2812-2821   Jan 2004
Deformation microstructures were studied in ferritic stainless steels during cold bar rolling and swaging to total true strains about 7. Two steels, i.e. Fe-22Cr-3Ni and Fe-18Cr-7Ni with coarse-grained ferritic and fine-grained martensitic initial...
Y. Kimura, Y. Sakai, T. Hara, A. Belyakov, A. Belyakov, K. Tsuzaki
Scripta Materialia   49 1111-1116   Dec 2003
The hydrogen induced delayed fracture of ultrafine grained 0.6% O steel with dispersed oxide particles was discussed. The MM of 0.6% O steel powder followed by consolidation at 700 °C resulted in the ultrafine grained steel having an average ferri...
A. Belyakov, A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Scripta Materialia   48 1463-1468   May 2003
Annealing softening mechanisms operating in cold-worked Fe-O steels were studied at 700 and 800 °C. Primary recrystallization develops only in 0.2%O samples after cold deformation of ε≥ 70%. In samples containing 0.6%O, static recovery is the only...
Yuuji Kimura, Setsuo Takaki, Hideto Goto
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   45(3) 283-288   Jan 1998
Microstructures and mechanical properties were investigated for Fe-25mass%Cr-(1.5-1.8)mass%C alloys produced by mechanical alloying. Mixtures of iron , chromium and graphite powders were ball-milled in Ar atmosphere and then hot-pressed at 1273K i...
A. Belyakov, A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Scripta Materialia   48 1111-1116   Apr 2003
The microstructure evolution in iron oxides processed by mechanical milling and consolidated warm bar rolling was studied. The milling was seen to promote the development of a submicrocrystalline structure with nano-sized dispersed oxides in the b...
Y. Kimura, S. Takagi, T. Hara, S. Terasaki, K. Tsuzaki
Journal De Physique. IV : JP   112 I 403-406   Jan 2003
The influence of the grain size of the prior-austenite on the hydrogen-induced delayed fracture property was investigated for a medium carbon tempered martensitic steel (JIS-SCM440) with a tensile strength of 1400MPa. Thermomechanical treatment, w...
Yuuji Kimura, Setsuo Takaki, Hideto Goto
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy   43(5) 584-589   Jan 1996
Fe-C system hard alloys were produced from mechanically alloyed powders and their properties were examined by means of hardness testing and microstructural examinations. Mixtures of iron and graphite powders(Fe-2-6mass%C) were mechanically alloyed...
A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   34 131-138   Jan 2003
The structural changes upon annealing of an ultrafine-grained iron containing dispersed oxides were studied. The starting material was subjected to mechanical milling followed by consolidating bar rolling. The fine-grained microstructures were ess...
SAWAI Tatsuaki, KIMURA Yuji, TSUZAKI Kaneaki, TAKEUCHI Etsuo, MATSUOKA Saburo
TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A   68(665) 49-56   Jan 2002
High-cycle fatigue properties up to 108 cycles were investigated for a modified-ausformed spring steel SUP 12 with the tensile strength &delta;B=1772 MPa. The surface-type fracture occurred at the higher stress level. On the ...
Andrey Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   33 3241-3248   Jan 2002
The changes an pct alloy during milling by structural in Fe-0.6 pet O mechanical milling followed consolidation through rolling were studied. The iron-iron oxide powders were mechanically milled in an argon atmosphere for various times from 20 to ...
Yuuji Kimura, Masatomo Kamada, Setsuo Takaki
Journal of the Japan Society of Powder and Powder Metallurgy   40(3) 315-319   Jan 1993
Mechanical alloying process of the mixture of ferritic(δ) and austenitic(γ) stainless steel powders has been investigated by means of X-ray diffraction and EPMA line analysis. The chemical compositions of δ and γ powders used is Fe-27mass%Cr-7mass...
A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Scripta Materialia   45 1213-1219   Nov 2001
The annealing behaviour of the Fe-1.5%O steel with a grain size of about 0.2 μm was investigated using mechanical milling techniques. The structural analysis of the given samples was conducted using transmission electron microscope (TEM) at 200 kV...
A. Belyakov, Y. Sakai, T. Hara, Y. Kimura, K. Tsuzaki
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science   32 1769-1776   Jan 2001
The microstructure and the strength of an iron mechanically milled with various amounts of oxygen (i.e., 0.2, 0.6, and 1.5 mass pct) were studied. The samples were subjected to a mechanical milling in an argon atmosphere for 100 hours followed by ...
Yuuji Kimura, Yuuji Kimura, Shinich Suejima, Shinich Suejima, Shinich Suejima, Hideto Goto, Setsuo Takaki
ISIJ International   40    Dec 2000
Microstructures and mechanical properties were investigated in ultra fine-grained oxide-dispersion steels with 24 mass% Cr ferrite matrix fabricated from mechanical milled powders. Powder mixtures of Fe, Cr and Y 2O 3 were mechanically milled in a...
HIDAKA Hideyuki, KIMURA Yuuji, TAKAKI Setsuo
Journal of the Japan Society of Powder and Powder Metallurgy   46(12) 1256-1260   Dec 1999
The mechanically milled Fe-0.8mass%C alloy powder (MM powder) was packed in stainless steel tubes and hot-rolled to consolidate powder to the bulk material with full density (MM bulk material), and the mechanism during consolidation of the MM powd...
H. Hidaka, H. Hidaka, T. Suzaki, T. Suzaki, Y. Kimura, S. Takaki, S. Takaki
Materials Science Forum   304-306 115-120   Dec 1999
Mechanical milling using high energy ball mill was applied to Fe-(0-3. 8)mass%C alloy powders with (ferrite+cementite) two-phase structures to give an ultimate large strain to the powders. Relation between strength and niicrostructure was investig...
Yuuji Kimura, Setsuo Takaki, Shinichi Suejima, Ryuji Uemori, Hiroshi Tamehiro
ISIJ International   39 176-182   Dec 1999
Mechanical milling using a high energy planetary ball mill was applied to the powder mixtures of iron, chromium and yttria (Y2O3) (Fe-24mass%Cr-0-15mass%Y2O3) to introduce a very large strain into the iron-base matrix, and microstructural changes ...
KIMURA Yuuji, TAKAKI Setsuo, GOTO Hideto
Journal of the Japan Society of Powder and Powder Metallurgy   45(3) 283-288   Mar 1998
Microstructures and mechanical properties were investigated for Fe-25mass%Cr-(1.5-1.8)mass%C alloys produced by mechanical alloying. Mixtures of iron, chromium and graphite powders were ball-milled in Ar atmosphere and then hot-pressed at 1273K in...

Research Grants & Projects

 
Strengthening and Toughening of Iron and Steel