Cu双晶的循环形变行为与疲劳裂纹萌生Ⅱ.疲劳裂纹萌生与早期扩展  

CYCLIC DEFORMATION BEHAVIOR AND FATIGUE CRACK INITIATION IN COPPER BICRYSTALS

作　　者：胡运明[1] 王中光[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110015

出　　处：《金属学报》1997年第8期824-830,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金!19392300-4

摘　　要：用扫描电镜（SEM）观察了受应变疲劳载荷作用的Cu双晶的表面形貌，发现晶界是疲劳形变双晶最有利的裂纹萌生地点．在滑移带撞击晶界的地方，特别是在几条粗滑移带共同撞击晶界的地方观察到许多疲劳微裂纹；并且发现与平行晶界双晶相比，垂直晶界双晶中极有利于疲劳裂纹沿晶界作早期扩展一种PSB－GB疲劳裂纹萌生机制可用来解释这些沿晶疲劳裂纹的形成．Surface morphology of fatigued copper bicrystals was investigated by a scan-ning electron microscopy(SEM). It was found that the grain boundaries are the preferred sites for fatigue crack initiation in the fatigued bicrystals. A large number of fatigue microcracks was observed at the sites of grain boundaries where slip bands impinged, especially at the sites where several intense slip bands impinged. And it was found that, compared with the bicrystal specimens with a grain boundary parallel to loading axis, the bicrystal specimens with a grain boundary perpendicular to loading axis are quite favorable for the fatigue crack early growth along grain boundary. A PSB-GB model of fatigue crack initiation can be used to explain the initiation of the intergranular fatigue cracks.

关 键 词：双晶 疲劳裂纹 早期扩展 铜 循环形变 

分 类 号：O741.2[理学—晶体学] TG146.11[一般工业技术—材料科学与工程]