粗晶粒铸轧AZ31镁合金的高温拉伸性能  

High temperature tensile performance of twin-roll casted and coarse-grained AZ31 magnesium alloy

作　　者：聂保新[1] 乔军[1] 张永彬[1] 张庆丰[1] 陈敏[1] 

机构地区：[1]辽宁科技大学材料与冶金学院,辽宁鞍山114051

出　　处：《辽宁科技大学学报》2011年第5期470-473,478,共5页Journal of University of Science and Technology Liaoning

基　　金：国家自然科学基金资助项目(50801034)

摘　　要：研究了具有较大晶粒尺寸铸轧态AZ31镁合金的高温拉伸性能。通过热处理获得晶粒尺寸d=27.8μm的板材,对不同试样,在温度分别为300,350,400,450℃恒温条件下,以10^(-3)s^(-1)和10^(-2)s^(-1)恒定拉伸速率对试样进行拉伸至失效实验。结果表明,粗晶粒AZ31镁合金在450℃和10^(-3)s^(-1)条件下达到最大的延伸率106.7%。拉伸试样断口形貌的分析表明,450℃时出现丝状物质是合金出现液态Zn的结果。少量的液相可以释放应力集中和协调此时的变形过程。与细晶粒铸轧态AZ31相比,在拉伸条件相同和晶粒尺寸不同的情况下,粗晶粒的塑形较低,其原因是晶界滑移在变形时所作贡献少。High temperature tensile performance of a twin-roll casted AZ31 magnesium alloy with large grain size is investigated. The grain size （ d = 27.8 μm） is coarsen through heat treatment. Under constant temperatures （300,350,400 and 450℃ ）, elongation-to-failure tests are conducted under constant tensile rates of 10^-3s^-1 and 10 ^-2s^-1. The investigation suggests that the maximum elongation of 106. 7% is obtained at 450 ℃ and 10^-3s^-1. Fracture morphology of the tensile specimens shows that the thread of liquid Zn appears at 450℃. The existence of a few liquid phase could release the stress concentration and coordinate deformation process. By comparing with the fine-grained AZ31, the investigated AZ31 alloy with larger grains offers a lower tensile ductility under the same tensile condition, which may be ascribed to the less contribution of grain boundary sliding to ductility.

关 键 词：铸轧态AZ31 高温拉伸性能 粗晶粒 超塑性 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TG359[金属学及工艺—金属材料]