退火对AZ31镁合金板组织与性能的影响  

Effect of annealing on microstructure and properties of AZ31 magnesium alloy sheet

作　　者：陈贝[1] 陈惠芬[1] 徐春[1,2] 庞灵欢 王泽民[1] 

机构地区：[1]上海应用技术学院材料科学与工程系,上海201418 [2]上海应用技术学院机械工程学院,上海201418

出　　处：《金属热处理》2015年第11期48-52,共5页Heat Treatment of Metals

基　　金：上海市科委重点支撑项目(13520503100)

摘　　要：镁合金板轧制后会出现大量形变孪晶,对使用性能带来非常不利影响。通过对镁合金板退火处理,用光学显微镜、扫描电子显微镜、拉伸试验机及X射线衍射仪,对AZ31镁合金板材轧制后不同退火制度下的显微组织、力学性能和衍射峰宽化现象进行了研究。结果表明,AZ31镁合金轧制后出现的大量形变孪晶,在200-350℃退火后,发生回复再结晶,孪晶基本消失;240℃退火1 h,组织为细小等轴晶粒,伸长率达到20.6%;轧制后的拉伸断裂面沿一定的晶面分离,退火后拉伸断口呈明显韧窝状,为典型的韧性断裂。轧制使层错率升高,在X射线衍射谱中表现为峰形宽化;退火使层错率降低,伸长率提升。A large number of deformation twins appearing after rolling have a negative effect on properties of magnesium alloy sheet.Microstructure,mechanical properties and diffraction peak width of the rolled AZ31 magnesium alloy sheets annealed at various temperatures for different time were investigated by means of optical microscope（ OM）,scan electron microscope（ SEM）,tensile testing machine and XRD meter.The results show that a great amounts of deformation twins appear at rolling,but disappear after annealing at 200-350 ℃,and the recrystallization of microstructure also occurs.Microstructure of the sample annealed at 240 ℃ for 1 h is fine equiaxed grains and the elongation is 20.6%.After rolling,the tensile fracture surface is separated along a certain crystal surface and after annealing it shows ductile fracture.Rolling makes stacking fault of the AZ31 magnesium alloy sheets increase,which demonstrates a peak broadening in X ray diffraction.The stacking fault decreases after annealing,whereas the elongation increases.

关 键 词：AZ31镁合金 力学性能 显微组织 X射线衍射 峰宽 

分 类 号：TG166.4[金属学及工艺—热处理]