Mechanical characterization of local deformation behavior in the vicinity of grain boundary

将纳米尺度的力学表征应用于钢的晶界，分析其基本变形行为，探讨晶界强化的机理。塑性起始的临界应力在晶界处低于晶粒内部。通过TEM原位纳米压痕，发现流动应力随着位错的急剧增殖而下降。即使晶界角度较大，也没有明显的位错堆积。

Nano-scale mechanical characterization was applied to grain boundary of steels and fundamental deformation behavior was analyzed to consider the mechanism of grain boundary strengthening. The critical stress for the plasticity initiation is lower for the grain boundary than that for the grain interior. Through the in-situ nanoindentation in a TEM, it was found that the flow stress dropped with drastic dislocation multiplication. There was no remarkable dislocation pile-up at the grain boundary even though the grain boundary has a large angle.