Microstructure Evolution during Reverse Transformation of Austenite from Tempered Martensite in Low Alloy SteelT.Shinozaki; Y.Tomota; T.Fukino and T.Suzuki, Microstructure evolution during the reverse transformation of low alloy steel consisting of lath martensite and chromium carbide was examined using in-situ electron backscatter diffraction at high temperatures. Austenite grains nucleated during the reverse transformation were categorized into two types: austenite grains nucleated along the lath boundaries with almost the same crystal orientation as the prior austenite (type A), and austenite grains nucleated at the prior austenite grain boundaries or inside the prior austenite grains with a different crystal orientation (type B). After the reverse transformation was finished, the prior austenite grains were reconstructed by the rapid growth and coalescence of type-A grains, which was called the "austenite memory phenomenon." Here, misorientation remained in the reconstructed austenite grains. Hence, upon heating to a higher temperature, type-A grains were invaded and were eventually replaced by type-B grains, resulting in a new fine-grained microstructure; this was similar to recrystallization. Therefore, these results showed that the austenite memory phenomenon occurred when the nucleation and growth of type-A grains was more dominant than those of type-B grains and that the degree of grain refinement depended on the nucleation and growth rate of the type-B grains., IRON STEEL INST JAPAN KEIDANREN KAIKAN
ISIJ International, 01 Mar. 2017,
[Reviewed] The Residual Stress Control of the Fastening Bolt for Bridges
Takanori Ebata; Hitoshi Yokota; Tetsuya Suzuki
2017 ACENS,,Asian Conference on Engineering and Natural Sciences,2017 ACENS, Jan. 2017, [Reviewed]
Synthesis of PuNi3-type PrCo3 and its hydrogen absorption-desorption propertyKenji Iwase; Kazuhiro Mori; Shinnosuke Shimizu; Suguru Tashiro; Tetsuya Suzuki, We synthesized the intermetallic compound PrCo3 with the PuNi3-type structure. The structural parameters were refined by the Rietveld method. The refined lattice parameters were a = 0.5076(1) nm and c = 2.4831(6) nm. The pressure-composition (P-C) isotherm of PrCo3 was measured at 413 K. The maximum hydrogen capacity reached 0.95 H/M. Two plateaus were observed in the absorption-desorption process. The hydrogenation properties were reversible. The structure change of the hydride phase was investigated by X-ray diffraction. The space group of the full hydride phase (PrCo3H3.8) was determined to be R32; the metal sublattice of the original alloy (space group R-3m) transformed to R32 during the hydrogen absorption process. The volume expansions of the unit cell, and the CaCu5-type and MgZn2-type cells of the full hydride phase from the original alloy were 25.0%, 18.4%, and 22.7%, respectively. The structural change was accompanied by anisotropic lattice expansion. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Sep. 2016,
[Reviewed] Accumulating Spot Joining of Aluminum and Copper Thin Plates by Indirect Friction Stir Joining
S. Igarashi; T.Suzuki; M. Tashiro; T. Nagano
9th Pacific Rim International Conference on Advanced Materials and Processing (PRICM9), Aug. 2016, [Reviewed]
Structural change of NdNi3 during hydrogen absorption-desorption cycleKenji Iwase; Kazuhiro Mori; Suguru Tashiro; Hitoshi Yokota; Tetsuya Suzuki, The structural change of NdNi3 during the hydrogen absorption-desorption cycle and the P-C isotherm have been investigated. The maximum hydrogen capacity achieved in the first absorption process is 1.05 H/M. After the first desorption, 0.75 H/M of hydrogen capacity remains in the alloy. The trigonal crystal structure of the original alloy (R-3m) transforms to monoclinic (C2/m) in the first absorption. The crystal structure of the hydride phase remains monoclinic during the first desorption. The metal sublattice expands anisotropically during phase transformation from the alloy to the monoclinic hydride (NdNi3H4.0); a, b, and c axes expand by 8%, 7%, and 44%, respectively. The volumes of the unit cell, and the Nd2Ni4 and NdNi5 cells expand by more than 60%. Phase transformation of NdNi3H is irreversible during the first absorption-desorption cycle. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Feb. 2016,
[Reviewed] Effect of Mg substitution on hydrogen absorption-desorption behavior and crystal structure of Gd2-xMgxNi7Kenji Iwase; Naoyoshi Terashita; Kazuhiro Mori; Suguru Tashiro; Hitoshi Yokota; Tetsuya Suzuki, The hydrogen absorption-desorption behavior and the crystal structure of Gd2-xMgxNi7 were investigated by pressure composition (PC) isotherm measurements and X-ray diffraction (XRD). Gd1.5Mg0.5Ni7 consists of two phases: 75% Gd2Co7-type structure and 25% PuNi3-type structure. Mg atoms substitute at the Gd site of the MgZn2-type cell in both Gd2Co7-type and PuNi3-type phases. In the hydrogen-free alloy after the PC isotherm measurement, the volumes of the (Gd/Mg)Ni-2 and GdNi5 cells of the Gd2Co7-type phase do not change appreciably, while those of the PuNi3-type phase experience shrinkage and expansion, respectively. A plateau region of Gcl(1.5)Mg(1.5)Ni(7) is observed between 0.06 H/M and 0.82 H/M. The reversible hydrogen content in the absorption desorption cycle is approximately 1.0 H/M. The enthalpy of hydride formation is evaluated as -24 kJ/mol H-2 from the Van't Hoff plot. The absorption desorption behavior is excellent even at low temperatures below 243 K. The hydrogen storage property of Gd1.5Mg1.5Ni7 is markedly improved by Mg substitution. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Jan. 2016,
[Reviewed] Crystal structure analysis of La2Ni6CoDx during deuterium absorption process
K.Iwase; K.Mori; S.Tashiro; H.Yokota; T.Suzuki
Inorg. Chem, Aug. 2015, [Reviewed]
Effects of Mg substitution on crystal structure and hydrogenation properties of Pr1−xMgxNi3
Kenji Iwasea; Naoyoshi Terashita; Kazuhiro Mori; Suguru Tashiro; Hitoshi Yokota; Tetsuya Suzuki
International Journal of Hydrogen Energy, Jun. 2014, [Reviewed]
中性子回折によるフェライト単相鋼のひずみ時効硬化異方性の検討
鈴木徹也; 山中啓輔; 石野まゆ子; 篠原康浩; 長井健介; 津留英司; 徐平光
鉄と鋼, 01 Jun. 2012, [Reviewed]
フェライト鋼の加工硬化異方性に及ぼすひずみ負荷経路とひずみ時効の影響
長井健介; 篠原康浩; 津留英司; 石野まゆ子; 鈴木徹也
鉄と鋼, 01 Jun. 2012, [Reviewed]
Control of Aluminum Concentration on Iron Surface by Powder Eutectic Coating Using Laser-HeatingMayuko Ishino; Tetsuya Suzuki, A method for coating iron with a mixture of aluminum, titanium and iron powder was successfully developed using laser-heating. The aluminizing process included control of the aluminum concentration on the iron surface. A double heating process is considered to be effective for homogenization of the coated layer. © 2012 The Japan Institute of Metals.
Materials Transactions, 25 May 2012,
[Reviewed] Corrosion Experiments and,Development of Aluminum-Alloy,Coating on Type 316SS for Nuclear,Systems Using Liquid Lead-BismuthY. Kurata; H. Yokota; T. Suzuki, An Al-alloy coating method using Al, Ti and Fe powders and the laser beam heating has been developed for nuclear systems using liquid lead-bismuth eutectic (LBE). Main defects formed in the coating process were surface defects and cracks. It was effective to decrease a laser beam scanning rate to 20 mm/min to avoid surface defects. It was necessary to adjust the Al concentration in the coating layer to be lower than 12 wt.% in order to avoid significant cracking. A static corrosion test was conducted in liquid LBE at the controlled oxygen concentrations of 10(-6)-10(-3) wt.% at 550 degrees C for 3000 h. The Al-alloy coating layer on 316SS prevented severe corrosion attack such as Ni dissolution, partial loss of grains and LBE penetration which were observed in 316SS without AI-alloy coating. Liquid LBE penetrated into the surface defects formed in the Al-alloy coating layers produced using a laser beam with the scanning rate of 60 mm/min. The AI-alloy coating layer, which was formed without surface defects and cracks under the optimum condition of the scanning rate of 20 mm/min, exhibited good corrosion resistance in liquid LBE. (C) 2012 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
Journal of Nuclear Materials, 2012,
[Reviewed] Development of Aluminum Alloy,Coating for Advanced Nuclear Systems Using Lead AlloysKurata Yuji; Yokota Hitoshi; Suzuki; Tetsuya, Small and medium reactors using lead alloys as coolant are one of the promising reactor concepts with improved safety because of their thermal-physical and chemical properties. This paper focuses on development of Al-alloy coating for nuclear systems using liquid lead-bismuth eutectic(LBE). Since corrosion attack becomes severe against structural steels at high temperatures in liquid LBE, it is necessary to improve corrosion resistance of steels. An Al-alloy coating method using Al, Ti and Fe powders, and laser beam heating has been developed. Main defects formed in an Al-powder-alloy coating process are surface defects and cracks. Conditions required to avoid these defects are employment of the laser beam scanning rate of 20 mm/min and adjustment of the Al concentration in the coating layer. According to results of the corrosion tests at 550 C in liquid LBE, the Al-alloy coating layers on 316SS protect severe corrosion attack such as grain boundary corrosion and LBE penetration observed in 316SS without coating. The good corrosion resistance of the Al-alloy coating is based on the thin Al-oxide film which can be regenerated in liquid LBE. From the viewpoints of the soundness of produced Al-powder-alloy coating layers and preservation of their corrosion resistance, it is estimated that the range of the adequate Al concentration in the coating layer is from 4 to 12 wt%., AMER SOC MECHANICAL ENGINEERS
ASME 2011 Small Modular Reactors Symposium (SMR 2011),Hyatt Regency on Capitol Hill (ワシントンDC,米国), 28 Sep. 2011
Applicability of Al-Powder-Alloy Coating to Corrosion Barriers of 316SS in Liquid Lead-Bismuth EutecticY. Kurata; H. Sato; H. Yokota; T. Suzuki, A new Al-alloy coating method using Al, Ti and Fe powders has been applied to 316SS in order to develop corrosion resistant coating in liquid lead-bismuth eutectic: (LBE). The 316SS plates with coating layers of different Al concentrations were exposed to liquid LBE with controlled oxygen concentrations of 10(-6) to 10(-4) mass% at 823 K for 3600 ks. While surface oxidation and grain boundary corrosion accompanied by liquid LBE penetration are observed in 316SS without Al-alloy coating, the Al-alloy coating is effective to protect such severe corrosion attacks in liquid LBE. Although the coating layer containing 2.8 mass% Al does not always keep sufficient corrosion resistance, good corrosion resistance is obtained through the Al-oxide film formed in liquid LBE in the coating layer where the average Al concentration is 4.2 mass%. Cracks are formed in the coating layer containing 17.8 mass% Al during the coating process. The Al-powder-alloy coating applied to 316SS is promising as a corrosion resistant coating method in liquid LBE environment. [doi:10.2320/matertrans.M2010337], JAPAN INST METALS
Materials Transactions, 2011,
[Reviewed] Development of,Aluminum Powder Alloy Coating for,Innovative Nuclear Systems with,Lead-bismuth
Kurata Yuji; Sato Hidetomo; Yokota; Hitoshi; Suzuki Tetsuya
OECD/NEA International,Workshop on Structural Materials for,Innovative Nuclear Systems (SMINS-2),Daejeon、,Republic of Korea (大田、韓国), 30 Aug. 2010
High Tensile Strength of Low-Carbon Ferritic Steel Subjected to Severe Drawing
T. Suzuki; Y. Tomota; A. Moriai; H. Tashiro
Materials Transactions, 25 May 2009, [Reviewed]
Hierachical characterization of heterogeneous deformation behavior of lamellar pearlite in eutectoid steelY. Adachi; S. Morooka; H. Igari; T. Suzuki; Y. Tomota, Heterogeneous deformation behavior of lamellar pearlite in a eutectoid steel was studied with a particular attention to the microstractural hierarchy. In- situ neutron diffraction study demonstrated that the applied external stress was partitioned both (1) between cementite lamella and ferrite, which causes so- called phase stress and (2) among ferrite with a different orientation, which causes intergranular stress. In addition to the two types of internal stress, EBSD analysis revealed that the local deformation proceeds differently depending on the cementite lamella direction as well, which might cause (3) cementite lamella direction-driven intergranular stress. Even within a colony where the cementite lamella direction is identical, local deformation proceeds inhomogeneously at a lamella level, which likely causes cementite lamella imperfection-driven intergranular stress. The reason for the heterogeneous deformation behavior at each scale level was discussed from the view point of local microstructure heterogeneity characterized by TEM and 2D/3D EBSD analyses.
Netsu shori, 49, Special issue, 2009,
[Reviewed] In Situ TOF Neutron Diffraction for Isothermal Ferrite Transformation during Thermo-Mechanically Controlled Process of Low Alloy Steel
P.G.Xu; Y.Tomota; T.Suzuki; M.Yonemura; E.C.Oliver
Netsu shori, 49, Special issue, 2009, [Reviewed]
中性子回折角度分散法による塑性加工を受けた鋼の応力・組織因子解析システムの開発
龍福進; 鈴木徹也; 鈴木裕士; 友田陽
鉄と鋼, 2008, [Reviewed]
Bulk Texture Measurement of Interstitial-Free Annealed Steel using Gaussian Integrated Intensities of Neutron Diffraction SpectraP.G.Xu; Y. Tomota; H. Suzuki; T. Suzuki; S. Machiya; F. X. Yin, {110}, {200} and {211} neutron diffraction profiles of an interstitial-free annealed steel sheet were measured on 5 x 5 degrees stereographic angle grids, and several evaluation methods of diffraction intensity were employed to calculate the bulk texture, including the peak intensity at a constant 2theta angle, the simply summed intensity in a constant 2theta angle spread and the Gaussian integrated intensity obtained by single peak fitting of each profile. The comparison among differently evaluated bulk textures shows that a stronger {111} < UVW > fiber component and a weaker {001} < 110 > rotated cube component appear in the texture of investigated steel and the Gaussian integrated intensity method with proper coefficient constraints possesses a higher sensitivity to both weak texture components and strong ones. The crystallographic orientation maps obtained from electron backscattering diffraction and the bulk textures estimated from X-ray diffraction confirm the feasibility of the neutron bulk texture based on the Gaussian integrated intensity, suggesting that it can be suitably utilized to evaluate the global orientation distribution characteristics of heterogeneous materials. [doi: 10.2320/matertrans.MRA2008086], JAPAN INST METALS
Materials Transactions, 2008,
[Reviewed] レーザー加熱を用いた鉄の局所表面アルミニウム粉末被覆
鈴木徹也; 田家真紀子; 森田友晴; 林照剛; 村上浩二; 友田陽; 前川克廣
鉄と鋼, 2007, [Reviewed]
Strength and deformation behavior of bulky cementite synthesized by mechanical milling and plasma-sinteringT.Terashima; Y.Tomota; M.Isaka; T.Suzuki; M.Umemoto; Y.Todaka, Deformation behavior of bulky cementite was investigated by compression, bending and tension tests at various temperatures and strain rates. Specimens of cementite {(Fe0.95Mn0.05)(75)C-25} were prepared by plasma-sintering from a mixture of mechanically milled Fe, Mn and graphite powders. The maximum compressive strength observed was 3.2 GPa at 573 K. At room temperature, specimens exhibited brittle fracture under compression where the fracture strength was between 2 and 3 GPa. At elevated temperatures under all types of loading modes, specimens showed high ductility, where grain boundary sliding was the dominant deformation mechanism because of the favorable grain size for superplasticity (less than 1.0 mu m). (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Scripta Materiallia, 2006,
[Reviewed] Plasma nitridation of aluminized high purity ironK Murakami; N. Nishida; K. Osamura; Y. Tomota and T. Suzuki, Surface treatment of high-purity iron by powder liquid coating aluminization and plasma nitridation is investigated with respect to the mechanism of hardening and nitrogen diffusion. Grain boundaries in the aluminized layer are found to be preferentially nitrided in the early stage of nitridation, accompanied by the formation of gamma '-Fe4N platelets in the substrate. Aluminization and nitridation increase the hardness from HV110-120 for the original alpha-Fe(Al) to HV1200-1500 for the modified specimen, which consists of an alpha-Fe(Al) matrix with gamma '-Fe4N and rocksalt AIN. Transmission electron microscopy observation reveals the AIN to be present in the form of platelets of 2-3 nm in thickness with an orientational relationship of (001)(alpha)//(001)(AIN) and [110](alpha)// [100](AIN) (Baker Nutting relationship). The kinetics of plasma nitridation is formulated, and good agreement with the experimental results is obtained when first- or second-order reactions are assumed for the formation of AIN under constant N flux at the surface. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Acta Materiallia, May 2005,
[Reviewed] AlおよびTi素粉末を用いた鉄鋼材料の耐酸化被覆
鈴木徹也; 寺田真一; 友田陽
鉄と鋼, Jan. 2005
溶融塩ホウ化処理によるTiAlの耐酸化性改善
横田仁志; 鈴木徹也
鉄と鋼, Jan. 2005
粉末液相被覆法を用いたAl拡散浸透およびプラズマ窒化処理による炭素鋼および合金工具鋼の表面改質
村上浩二; 西田典秀; 長村光造; 鈴木徹也; 友田陽
鉄と鋼, Jan. 2005
18Ni、17Ni-0.2CおよびSM490鋼マルテンサイトの動的再結晶挙動
包耀宗; 足立吉隆; 遠峰裕二; 鈴木徹也; 徐平光; 友田陽
鉄と鋼, 2005, [Reviewed]
Dynamic recrystallization by rapid heating followed by compression for a 17Ni-0.2C martensite steelY.Z. Bao; Y. Adachi; Y. Toomine; P.G. Xu; T. Suzuki; Y. Tomota, A 17Ni-0.2C martensite steel was rapidly heated below the austenite formation temperature and deformed ill compression. Continuous dynamic recrystallization was observed. The behavior is similar to that in a ferrite-pearlite steel but the onset strain is much smaller. Sub-micron ferrite grains were obtained through the dynamic recrystallization. (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Scripta Materialia, 2005,
[Reviewed] パーライト鋼の塑性変形挙動に及ぼす階層的不均一変形と集合組織の影響
諸岡聡; 鈴木徹也; 友田陽; 塩田佳徳; 神山崇
鉄と鋼, 2005, [Reviewed]
中性子回折による高周波焼入棒鋼の残留応力測定
徳田玄聖; 友田陽; 鈴木徹也; 川崎一博; 盛合敦; 皆川宣明; 森井幸生
鉄と鋼, Dec. 2004
Recovery and recrystallization behavior of a ferrite steel after large strain deformation
M.Uno; T.Suzuki; Y.Tomota; A.Moriai; N,Minakawa; Y.Morii; H.Tashiro; K.Nakamura
The 4th Korea – Japan Meeting on Neutron Science, Feb. 2004
Aluminization of high purity iron and stainless steel by powder liquid coatingKoji Murakami; Norihide Nishida; Kozo Osamura; Yo Tomota and Tetsuya Suzuki, Powder liquid coating is investigated metallographically as an aluminization technique for high-purity iron [Acta Mater., ill press] and stainless steel. In this process, Fe2Al5 forms initially during heat treatment, with c axis preferentially aligned with the sample normal. In Fe-18mass%Cr alloy, Cr exhibits almost the same concentration profile as Fe except for the temporary Formation of a Cr5Al8 network in the early stage of heat treatment. Fe-25Cr-18Ni alloy forms a thinner aluminized layer compared to the other substrates, and contains an Al-Ni-rich layer and spherical precipitates (ordered B2). The diffusion of Al and Ni in the system (B2/bcc/fcc) is simulated using a new formulation of the diffusion equation for the tertiary Fe-Al-Ni system taking the concentration-dependent interdiffusion coefficient into account. The bcc layer is found to be predominantly in a steady state due to the large interdiffusion coefficients, and characteristic uphill diffusion of Al in the B2 layer is attributed to the existence of Ni. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
Acta Materialia, 2004
中性子回折によるパーライト組織鋼における加工硬化の考察
蟹江厚臣; 友田陽; 鈴木徹也; 鳥居周輝; 盛合敦; 皆川宣明; 森井幸生; 神山崇
日本材料学会誌, 2004
Strength Anisotropy and Residual Stress in Drawn Pearlite Steel WireTetsuya Suzuki; Y. Tomota; M. Isaka; A. Moriai; N. Minakawa and Y. Morii, Strength anisotropy is found by tensile and compressive tests for a drawn pearlite steel wire, where the compressive tests are performed for prepared specimens along directions of 0, 45 and 90 degrees with respect to the drawing direction. The influence of annealing on such anisotropic strength is also examined. To make clear the origin of the strength anisotropy, texture and residual strain are measured using neutron diffraction. It is revealed that residual stresses in the ferrite and cementite phases are the cause of strength anisotropy., IRON STEEL INST JAPAN KEIDANREN KAIKAN
ISIJ Int., 2004
In situ neutron diffraction under tensile loading for heavily drawn steel wires with ultra-high strength
Yo Tomota; A. Kanie; Y. Siota; T. Suzuki; A. Moriai; N. Minakawa and Y. Morii
Acta Materialia, 2004
Anisotropic Residual Stresses in a Pearlitic Steel after Tensile Deformation
T.Suzuki; Y.Tomota; A.Moriai; N.Minakawa and Y.Morii
ATEM’03, Sep. 2003
Heterogeneous Deformation Behavior of Pearlite Steels Studied by Neutron DiffractionY.Tomota; A.Kanie and T.Suzuki, When plastic deformation is given to a pearlite steel, misfit strain generates between cementite and ferrite accompanying phase stress. Inhomogeneous plastic flow also takes place due to different [hk1] orientions of blocks resulting in generation of block stress as well as presumably due to different directions of lamellae in a bolck, colony stress. Neutron diffraction enables us to determine the phase stress and the block stress averaged within a whole specimen and to obtain some information on lamellar stress. In situ neutron diffraction measurements were carried out during tensile testing for variously heat-treated ferrite-cementite steels and the above internal stresses yielded by the inhomogeneous plastic deformation are discussed focusing on their effects on the yield strength and work hardening. The effects of volume fraction and shape of cementite on flow stress are well understood from the phase stress., TRANS TECH PUBLICATIONS LTD
Materials Science Forum Vols. 426-432, 2003
