摘要
用蚀坑法观察了 Zn 单晶解理裂纹前端位错。结果表明,裂纹前端位错密度分布具有 DFZ模型预言的特征,且裂纹尖端与第一个位错的距离 X_1(即 DFZ 值)以及范性区位错数 N 均与根据Majumdar 和 Burns 的 DFZ 理论推算数值吻合较好。在此基础上,对裂纹前端发射位错和位错屏蔽裂纹前端等问题作了讨论。
Dislocation distribution ahead of a cleavage crack tip in Zn single crystal isobserved by using etch pit technique.The results show that this distribution has the featurepredicated by the DFZ models,and both X_1,the distance from the crack tip to the first dis-location,and N_0,the total number of dislocations ahead of the crack tip,agree withMajumdar and Burns'DFZ theory.The problems of dislocation emission from the cracktip and dislocation shielding effect on the crack tip are also discussed based on the experi-mental results.
关键词
Zn单晶
裂纹前端
范性行为
dislocation etch-pit
dislocation-free zone
effective stress intensity factor
