合金化镀层拉伸过程中裂纹产生及扩展的原位观察  

In-situ observation for generation and propagation of crack in galvannealed coating during tensile process

作　　者：袁训华[1] 刘昕[1] 陈斌锴[1] 江社明[1] 张启富[1] 

机构地区：[1]钢铁研究总院先进金属材料涂镀国家工程实验室,北京100081

出　　处：《金属热处理》2010年第10期11-15,共5页Heat Treatment of Metals

基　　金：国家"十一五"科技支撑项目(2006BAE03A13);北京市科技计划项目(D07010300700702);国家自然科学基金(51071052)

摘　　要：用XRD分析铁含量不同的热镀锌合金化（GA）镀层的相结构,并用装配拉伸台的环境扫描电镜原位观察GA镀层在拉伸变形情况下表面裂纹产生、扩展及断裂的情况。结果表明,当铁含量为10wt%~15wt%时,镀层表面形成的裂纹间隙最小,抗粉化性能最好。在拉应力作用下,合金化镀层的破坏可分为两个过程：第一个破坏过程的主要表现形式是粉化,裂纹的扩展形式以张开型断裂为主;第二个破坏过程的主要表现形式是剥落,裂纹的扩展形式以滑开型断裂为主。镀层的断裂不是沿着某一固定的界面发生,而是在载荷作用的不同阶段发生不同类型的断裂和脱落,在不同的区域镀层断裂的界面不同。The phase structure of zinc galvannealed（GA） coatings with different Fe contents was analyzed by X-ray diffraction.The initiation and propagation of crack on the GA coating and the fracture of coating were observed during tensile process by use of an environmental scanning electron microscopy（ESEM） with in-situ investigation method.The results show that,when the Fe content is 10wt%～15wt%,the gap of cracks that formed on the surface of the coating is the least,and powdering-resistance performance of the coating is the best.The damaging process of the GA coating under tensile stress has two stages,at the first stage,the major damage displays as powdering,during this stage,tear-type fracture is the major form of the coating crack propagation.At the second stage,the major damage displays as flaking,slipping fracture is the major form of the coating crack propagation.The fracture of coating is not along the fixed interface but takes place different types fractures and flakes at the different stages of the loading,and the fracture interfaces of the coating are different in the different regions.

关 键 词：镀锌合金化 拉伸 裂纹产生及扩展 粉化和剥落 原位观察 

分 类 号：TG178[金属学及工艺—金属表面处理]