金属材料的晶界塑性变形机制

王江伟, 陈映彬, 祝祺, 洪哲, 张泽

Grain Boundary Dominated Plasticity in Metallic Materials

WANG Jiangwei, CHEN Yingbin, ZHU Qi, HONG Zhe, ZHANG Ze

图4 晶界变形行为的实验研究[30,31,36,54,55]

Fig.4 Experimental investigations on grain boundary deformation behaviors (a) deformation-induced grain rotation and grain agglomeration in nanocrystalline Ni[36] (t—time; the arrows indicate the growing grain) (b) shear-coupled grain boundary migration[30] (G1-G10—different grains in grain boundary networks; X1, X2—pre-existing precipitates acting as fiducial markers; T—tension direction) (c) movement of steps (s) on the 76.4°<001> grain boundary in Al bicrystals at 400oC[31] (s—2 nm height step; d—a lattice dislocation; x—a fixed point;tr.P—the trace of the glide plane; the red arrow indicates the motion of GB steps along the GB plane; the bottom black arrow indicates the dislocation d that glides in a {111} plane of G2) (d) dislocations move along the grain boundary and annihilate at the triple junction of the grain boundaries[31] (TJ—triple junction; d12, d13—moving grain boundary dislocations during grain boundary migration; arrows in the bottom schematic indicate the directions of grain boundary step motion, grain boundary migration and triple junction motion; SGB—subgrain boundary; b12—Burgers vector of grain boundary dislocation) (e) atomically resolved sliding at an asymmetric <110>-tilt 20.1° GB[54] (Atom-columns on the face of left grain are marked by green lowercase letters, and atom-columns on the face of right grain by red uppercase letters) (f) local atomic displacement during the motion of Σ7(2 3¯10)/[0001] grain boundary in α-Al2O3[55]