Quantitative Analysis of Dislocation Density in an Austenitic Steel after Plastic Deformation
Quantitative Analysis of Dislocation Density in an Austenitic Steel after Plastic Deformation
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DOI：
10.2320/jinstmet.j2014001
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发表时间：
2014-06-01
影响因子：
0.5
通讯作者：
Kubushiro, Keiji
中科院分区：
文献类型：
--
作者：
Umezaki, Shota;Murata, Yoshinori;Kubushiro, Keiji
利用X射线衍射和电子背散射衍射（EBSD）定量研究了奥氏体不锈钢在塑性应变下位错密度及其特征的晶粒尺寸依赖性。在650 ℃下用拉伸仪给出高达15%的各种塑性应变量，并采用三种晶粒尺寸（17、46和87 μ m）。每个晶粒中的晶体方向上的取向差由两个参数GOS（晶粒取向扩散）和KAM（内核平均取向差）确定。GN（Geometrically Necessary）位错密度由KAM参数估计。GOS参数随塑性应变量的增加而线性增加，而KAM参数随塑性应变的增加而增加，但表现出晶粒尺寸的依赖性。总位错密度随塑性应变的变化在KAM参数中表现出类似的趋势。结果发现，在塑性应变的总位错密度的差异是完全一致的GN位错密度取决于晶粒尺寸的差异。这些结果证实了使用几种样品在X射线实验中使用的TEM观察。
Grain size dependence of dislocation density and its character in austenitic stainless steels subjected to plastic strain was evaluated quantitatively by means of X-ray diffraction and Electron Back Scattering Diffraction (EBSD). Various amounts of the plastic strain up to 15% were given by a tensile instrument at 650 degrees C and three kinds of grain size (17, 46 and 87 mu m) were employed. Misorientation in crystal direction in each grain was determined by two parameters, GOS (Grain Orientation Spread) and KAM (Kernel Average Misorientation). GN (Geometrically Necessary) dislocation density was estimated from KAM parameter. GOS parameter increased with a linear relationship to the amount of plastic strain regardless of the grain size, whereas KAM parameter increased with increasing plastic strain but showed the grain size dependence. Change in total dislocation density with plastic strain showed a similar trend in KAM parameter. It is found that the difference in the total dislocation density at a plastic strain was consistent exactly with the difference in GN dislocation density depending on the grain size. These results were confirmed by TEM observations using several kinds of specimens used in X-ray experiments.