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佐藤 成男*; 菖蒲 敬久; 佐藤 こずえ*; 小川 博美*; 我妻 一昭*; 熊谷 正芳*; 今福 宗行*; 田代 仁*; 鈴木 茂*
ISIJ International, 55(7), p.1432 - 1438, 2015/07
被引用回数：13 パーセンタイル：53.65(Metallurgy & Metallurgical Engineering)冷間延伸されたパーライト鋼ワイヤにおける転位の分布および異方性を特徴付けるために、X線回折線プロファイル解析をシンクロトロン放射マイクロビームを用いて行った。一般に、塑性せん断ひずみはワイヤの中心よりも表面近くでより激しかったが、中心から表面まで転位密度分布はほぼ一定であった。一方、転位の再配列は、転位の細胞構造を進化させ、表面に近づくほど進んだ。異方性転位密度によって、軸方向および横断方向の硬さの差異が説明できることも明らかになった。高温での回折データに基づく線プロファイル解析を行った。セメンタイトの回収率は一定の速度で進行したが、フェライト相の回収率は温度依存性を示し、フェライト相の回収率はセメンタイト相の回収率とはあまり関係していなかった。
柴野 純一*; 梶原 堅太郎*; 塚本 拓也*; 河合 紘和*; 三浦 節男*; Zhang, S.*; 菖蒲 敬久; 小林 道明*
Materials Science Forum, 777, p.176 - 181, 2014/02
被引用回数：1 パーセンタイル：53.56(Materials Science, Multidisciplinary)A ductile damage progress of an aluminum single crystal with the prior activity of the single slip system under tensile loading was verified by a profile analysis using white X-ray obtained in BL28B2 beam line of SPring-8. In this study, the aluminum single crystal of the purity 6N was used as a specimen prepared in I-type geometry for tensile test. In profile analysis, an instrumental function was defined in consideration both of a divergence by a slit and a response function peculiar to the energy dispersive method. The Gauss component of integral breadth related to non-uniform strain and the Cauchy component of integral breadth related to crystallite size were determined by eliminating the broadening by the instrumental function from the diffraction profile of white X-ray. As a result, the characteristics of ductile damage progress near the notch of the aluminum single crystal were inspected from the distribution of both non-uniform strain and dislocation density.
諸岡 聡; 川崎 卓郎; Harjo, S.; 中田 伸生*; 塚田 祐貴*
no journal, ,
Hierarchical microstructure of pearlite and martensite in steel is caused by internal stress due to phase transformation. If internal stress can be quantitatively evaluated and controlled, new microstructure control technology will be created. However, internal stress due to eutectoid transformation is not easy to measure because thermal stress and transformation stress are superimposed. The purpose of this study is to quantitatively evaluate the internal stress evolved from pearlitic transformation by In-situ neutron diffraction technique. A pearlitic steel of 0.8C-1.5Mn wt.% was used in this study, and the following thermal process was performed; the solution heat treatment at 1323K for 1.8ks followed by immediate the isothermal heat treatment at 873K for 1.8 ks to obtain a predominantly pearlitic structure included lamellar ferrite and cementite. The austenitic-to-pearlitic transformation during the thermal process was monitored with a TAKUMI neutron diffractometer at J-PARC-MLF. The Rietveld refinements of diffraction patterns were performed using Z-Rietveld software to track the phase fractions and the lattice parameters. The elastic strains state of the ferrite and the austenite phases at 873K were observed from the evolutions of the lattice constants of ferrite and the austenite during pearlitic transformation. In particular, the cubical expansion during the transformation derived the hydrostatic pressure and resulted a compressive elastic strain in ferrite. On the other hand, the elastic strains state in cementite that was predicted by an amount of internal stress relaxation during thermal aging after pearlitic transformation, was approximately -0.28%. These results show that internal stresses during transformation can be quantitatively evaluated using in-situ neutron diffraction method.
