热处理对挤压镁合金AZ91拉伸变形与断裂行为的影响  

Effects of Heat Treatment on Tensile Deformation and Fracture Behavior of As-extruded AZ91 Magnesium Alloy

作　　者：严琦琦[1] 傅定发[1] 张辉[1] 陈振华[1] 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《热加工工艺》2006年第20期10-12,共3页Hot Working Technology

基　　金：湖南省重大专项计划基金资助项目(04GK1008-1)

摘　　要：通过金相显微组织观察和断口SEM分析,研究了热处理对挤压AZ91镁合金拉伸变形与断裂行为的影响。结果表明:AZ91镁合金固溶态与挤压态相比抗拉强度变化不大,但伸长率有较大幅度的提高,晶粒尺寸有所增大;时效峰值态的抗拉强度与固溶态相比有一定的提高,但伸长率有较大幅度的降低,合金固溶时效处理后伴有强化相粒子析出。AZ91合金挤压态和固溶态的断面都有韧窝特征,为微孔形核的韧性断裂机制,而在时效峰值态的断面上则呈现出了韧性与脆性混合断裂的特征。The effects of heat treatment on the microstructure, tensile deformation and fracture behavior of AZ91 magnesium alloy as-extruded were analyzed and studied by OM and SEM. The results show that comparing as-solution with as-extruded, the tensile strength of AZ91 alloy hardly changes, but its ductility and grain size increase significantly; comparing as-aged with as-solution,the tensite strength increases a litte,but its ductility reduces,with strengthening phase precipitating after solution and aging treatment.The fracture surface of AZ91 as-extruded and as-solution have dimple characteristic,and their fracture mechanism is ductile fracture.However, the fracture mechanism of AZ91 alloy as-aged changes from typical ductile tearing to mixture of ductile and brittle.

关 键 词：变形镁合金 挤压 热处理 拉伸 断裂 

分 类 号：TG146.22[一般工业技术—材料科学与工程]