热处理对挤压镁合金ZK60拉伸变形与断裂行为的影响  

Effects of heat treatment on tensile deformation and fracture of as-extruded ZK60 magnesium alloy

作　　者：陈水先[1] 张辉[2] 严琦琦[2] 李落星[2] 刘文华 

机构地区：[1]湖南大学材料科学与工程学院 [2]西北工业大学材料学院,陕西西安710072 [3]郴州工业学校,湖南郴州423000

出　　处：《金属热处理》2008年第6期85-88,共4页Heat Treatment of Metals

基　　金：国家科技部创新基金立项项目(07C26214301749);湖南省重大专项计划项目(04GK1008-1);湖南省自然科学基金项目(07JJ5067)

摘　　要：通过不同态ZK60镁合金的金相显微组织观察、力学性能试验和断口SEM分析,研究了热处理对挤压ZK60镁合金拉伸变形与断裂行为的影响。结果表明,ZK60合金固溶态与挤压态相比抗拉强度和伸长率均有相当程度的降低,而时效硬度峰值时的抗拉强度与固溶态和挤压态相比有一定的提高,但伸长率却有较大幅度的降低。合金固溶处理后晶粒较挤压态显著粗化,且合金固溶时效处理后伴有强化相粒子析出。ZK60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,而时效峰值态的断面上有解理河流和解理台阶,呈现出脆性解理断裂的特征。The effects of heat treatment on tensile deformation and fracture of the as-extruded ZK60 magnesium alloy were studied by the mechanical properties test, optical microscopy （OM） and scanning electron microscopy （SEM）. The results show that the tensile strength and elongation of the alloy as solution-treated are reduced compared with the as-extruded, and the tensile strength of the alloys are significantly enhanced by the special combination of solution and artificial aging treatment, but the elongation is greatly reduced. The grain sizes of the alloy are coarsened and fine particles are precipitated by solution and artificial aging treatment. The fractured surfaces of the alloy as-extruded or solution treated are featured as a typical ductile fracture, evidenced by the existence of dimples as a result of growth and coalescence of mierovoids. The fracture surfaces of the aged ZK60 alloy appear as the features of cleavage fracture and characterized by cleavage steps and cleavage rivers.

关 键 词：ZK60镁合金 挤压 热处理 拉伸 断裂 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG15[金属学及工艺—金属材料]