Spatial confinement-induced switchover in microstructure evolution during severe plastic deformation at micrometer length scales
Spatial confinement-induced switchover in microstructure evolution during severe plastic deformation at micrometer length scales
复制标题
微米长度尺度严重塑性变形过程中空间约束引起的微观结构演化切换
DOI：
10.1016/j.actamat.2014.07.004
复制
发表时间：
2014
期刊：
影响因子：
9.4
通讯作者：
M. Shankar
中科院分区：
文献类型：
--
作者：
S. Basu;M. Shankar
通过在扫描电子显微镜内进行大应变加工，研究了微米尺度样品体积中的严重塑性变形。变形区的原位二次电子图像的数字图像相关用于测量变形的力学。长度尺度对微观结构演变的影响，其特征在于使用取向成像显微镜/电子背散射衍射分析的变形区。在小尺度下，微结构演化机制中存在一个几何上必要的约束，并归因于几何约束和高应变梯度的耦合效应。提出了一个捕捉这种现象的唯象模型。结果表明，与传统的看法相反，由应变梯度引起的高结晶曲率阻碍晶粒细化在小的长度尺度，导致晶粒细化和破碎的异常抑制。
Severe plastic deformation in micrometer scale sample volumes is investigated by performing large strain machining inside a scanning electron microscope. Digital image correlation of in situ secondary electron images of the deformation zone is used to measure the mechanics of deformation. The effect of length scales on microstructure evolution is characterized using orientation imaging microscopy/electron backscattered diffraction analysis of the deformation zone. A geometrically necessary switchover in microstructure evolution mechanisms in small length scales is identified and attributed to a coupled effect of geometric confinement and high strain gradients. A phenomenological model capturing the switchover is proposed. It is shown that contrary to conventional perception, a high crystallographic curvature caused by strain gradients impedes grain refinement in small length scales, resulting in an anomalous suppression of grain refinement and fragmentation.
影响因子：
56.9
作者：
Csikor, Ferenc F.;Motz, Christian;Zapperi, Stefano
通讯作者：
Zapperi, Stefano