Ⅰ型裂纹尖端塑性区和无位错区及其对裂纹扩展的影响  

Mode Ⅰ crack tip plastic zone,dislocation-free zone and their effects on crack propagation

作　　者：钱才富[1] 李慧芳[1] 崔文勇[1] 

机构地区：[1]北京化工大学机电工程学院,北京100029

出　　处：《材料研究学报》2007年第6期599-603,共5页Chinese Journal of Materials Research

基　　金：国家自然科学基金10272020资助项目~~

摘　　要：用裂纹与位错的相互作用模拟了刃型位错从Ⅰ型裂纹尖端沿多个滑移面的发射,得到了裂纹尖端周围塑性区和无位错区的形状和大小.结果表明,与宏观断裂力学算出的塑性区形状相比,本文给出的塑性区向裂纹前方倾斜;无位错区的形状与塑性区的相似.以应变能密度因子理论为判据,当存在明显的无位错区时,塑性区使裂纹扩展的潜力下降,但扩展方向不变;而当塑性区充分发展、无位错区的作用减小或消失后,裂纹扩展的方向可能发生变化.Edge dislocation emissions from a Mode Ⅰ crack tip along multiple inclined slip planes are simulated, and plastic zones as well as dislocation-free zones are obtained. It is found that the shape of the mode Ⅰ plastic zone is similar to that obtained by von Mises or Tresca yielding criterion but leaning forward from the crack tip. The shape of dislocation-free zone is similar to that of plastic zone. With dislocation emission, the plastic zone becomes larger and larger while the dislocation-free zone is getting smaller and smaller. Judged by the strain energy density factor, the crack propagation potential decreases remarkably with dislocation emission. When a clear dislocation-free zone exists, the crack potential propagation direction will keep along the crack surface. However, when the plastic zone is fully developed or the dislocation-free zone is vanished, the crack potential propagation direction may also be changed.

关 键 词：材料科学基础学科 位错发射 塑性区 无位错区 裂纹扩展 

分 类 号：TG111.91[金属学及工艺—物理冶金]