T651态7075铝合金的显微组织与拉伸断裂机制  

Microstructure and Tensile Fracture Mechanism of 7075-T651 Aluminum Alloy

作　　者：李慧[1] 陈涛[1] 赵路远 黄俊[1,2] 吴玉程[1,2] LI Hui CHEN Tao ZHAO Lu-yuan HUANG Jun WU Yu-cheng(l.Department of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Chin Lab of Non-ferrous Metals Processing and Manufacturing, Anhui General Research Institute for Non-ferrous Metals, Hefei 230009, China)

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009 [2]安徽省有色金属材料与加工工程实验室,合肥230009

出　　处：《机械工程材料》2016年第11期38-43,共6页Materials For Mechanical Engineering

基　　金：国家自然科学基金资助项目(51201054);第51批博士后基金资助项目(2012M511400);教育部博士点基金资助项目(20120111120030)

摘　　要：对7075铝合金进行了T651热处理,研究了其显微组织、静载拉伸性能及断口形貌,分析了其显微组织与断裂机制的关系。结果表明:T651态7075铝合金具有较高的屈强比,抗拉强度和屈服强度分别为529,450 MPa;该合金中存在大量细小的MgZn2析出相,同时还存在粗大的Al7Cu2Fe夹杂物和富含硅的硬脆相;在拉伸应力的作用下,MgZn2析出相则倾向于沿界面脱粘形成微孔,Al7Cu2Fe等夹杂物易引发局部应力集中使夹杂物颗粒开裂,最终使合金以微孔聚合型方式断裂。T651 heat treatment was conducted on 7075 aluminum alloy. Then the microstructure, static tensile properties and fracture morphology of the alloy were investigated and the relationship between the microstructure and fracture mechanism was analyzed. The results show that the tensile yield ratio of the 7075-T651 aluminum alloy was relatively high and the tensile and yield strength was 529,450 MPa respectively. A large number of fine MgZn2 precipitates existed in the alloy, meanwhile coarse A17Cu2Fe inclusions and Si-rich hard phase were also observed. Under the tensile stress, the MgZn2 precipitate was apt to debond along the interface, resulting in the formation of micro-voids; the inclusions such as A17Cu2Fe were prone to cause local stress concentration, which led to cracking of the inclusion particles, finally resulting in the micro-void coalescence fracture of the alloy.

关 键 词：7075铝合金 T651热处理 显微组织 断裂机制 

分 类 号：TG13[一般工业技术—材料科学与工程]