Study on Relations among the Composition, Microstructure and Properties of Mg-Al-Zn Alloys
ZHANG Xi-yan~1,JIANG Feng~(1,3),ZHAO Min~2,LI Xue-qin~2,ZHOU Shi-jie~1,QI Lin-lin~1 (1.School of Material Science & Engineering, Southwest Jiaotong University, Chengdu 610031, P.R.China; 2.Nonferrous Metal Manufacturing Co., Chengdu Engine (Group) Co., Ltd., Chengdu 610067, P.R.China; 3.P.O. Box 677, Chengdu Aircraft Industrial (Group) Co., Ltd., Chengdu 610092,China)
Some of Zn and a little Ag are added into ZM5 magnesium alloy. On this basis, this paper studies the difference of the microstructures and properties between the new alloy and ZM5 and discusses the effect of solid solution and aging treatment on the microstructure of Mg-AI-Zn alloys and the relation between microstructure and properties. With the addition of the alloying element Zn, the amount and size of Y (Mg17Al12) phase increase with more complicated orientations of the slices, and the value of YS/UTS increases quite obviously while the elongation decreases in both conditions of T4 (solid solution) and T6 (solid solution + aging). The effect of heat-treatment on microstructure is remarkable, and the aging treatment after solid solution can obviously increase the value of YS/UTS of Mg-Al-Zn alloys. The amount, size and shape of Y phase at the grain boundary have close relation to the tensile properties.