脆性材料中的微裂纹尖端结构与断裂  

STRVCTURE AT MICROCRACK-TIP AND FRACTURE IN ENTIRE BRITTLE SOLID

作　　者：李志成[1] 刘路[1] 吴昕 贺连龙[3] 徐永波[1] 

机构地区：[1]中国科学院金属研究所材料疲劳与断裂国家重点实验室,沈阳110016 [2]Department of Mechanical and Engineering,Wayne state University [3]中国科学院金属研究所固体原子像开放实验室,沈阳110016

出　　处：《金属学报》2001年第5期503-506,共4页Acta Metallurgica Sinica

基　　金：国家自然科学基金NO.59971059;国家重点基础研究项目G19990650的资助

摘　　要：利用低载荷Ｖｉｃｋｅｒｓ压痕的方法在ＧａＡｓ单晶中诱发微裂纹，通过透射电子显微镜和高分辨电子显微镜对裂纹尖端进行了观察．结果表明，裂纹尖端前沿诱发了位错；沿着裂纹扩展方向出现了晶格扭曲，进而产生局部的无序化结构；无序化结构的扩大与连接形成具有１－２ｎｍ宽度的非晶窄带．裂纹在非晶窄带中萌生，并沿着非晶带扩展．弯曲的裂纹表面和具有一定宽度的裂纹尖端说明，裂纹的扩展并不是沿着某特定的原子面原子键脱开，而是在非晶窄带中由结合键较弱的原子之间的断键并相互连接的结果．The structures of the crack-tip induced during indentation in gallium arsenide single crystal have been investigated by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). The results reveal that there are dislocation generation, lattice distortion, and even change of lattice from crystal to disordered structure, leading to the occurrence of an amorphous narrow band with a width of 1-2 nm in front of crack-tip. The crack is not atomically sharp, and its propagation is the result of the decohesive between atoms in the amorphous narrow band.

关 键 词：GAAS单晶 低载荷压痕 裂纹尖端与裂纹扩展 电子显微技术 

分 类 号：TG111.91[金属学及工艺—物理冶金] TN304.23[金属学及工艺—金属学]