Effect of I-Zn_6Mg_3Y_1 on Mechanical Properties of AZ91D Alloy
Five species of Mg-Zn-Y alloys with I-Zn6Mg3Y1 phase were prepared by cast technology.The experimental alloys were cast,the mass ratio of Mg-Zn-Y alloys and AZ91D alloy is 2 ∶ 5.The microstructure of the samples was analyzed by OM and SEM.The composition and phases of the experiment alloys were analyzed by EDS,Vickers hardness and thermal expansion coefficient were tested,and the electrochemical corrosion was studied by potentiodynamic polarization measurements in 3.5wt%NaCl for 2 h.The results show that adding I-Zn6Mg3Y1 to AZ91D alloy,the hardness and corrosion resistance increase.After the immersion of the experimental alloy for 2 h,the corrosion current is increased by 1～2 order of magnitude compared with AZ91D alloy.In addition,the thermal expansion coefficient of the experimental alloy decreases,and thermal stability at high temperature greatly improves.