In order to increase quality of
die casting magnesium alloy,effect of vaccum
die casting on microstructure and properties of AZ91 magnesium alloy was investigated by using of optical microscope,scanning electron microscopy,mechanical property test,weight-loss method and electrochemical corrosion test. The experimental results show that vacuum
die casting can reduce the porosity of castings obviously,improve the relative density and microstructure uniformity,and the average grain dimension is about 30 um. The second phase Mg17Al12 distributes at the grain boundary in the form of plate and mesh shape. Compared with nomal one,the tensile strength,yield strength,elongation and hardness of the vacuum
die casting AZ91 alloy increase by 10.19%,33.07%,40.63% and 13.04%,respectively. Under condition of erosion in 3.5% NaCl aqueous solusion for 18 h,the corrosion rate of vacuum
die casting AZ91 alloy drops to 33.76% of normal one,and the corrosion current density of vacuum
die casting AZ91 alloy drops to 15.92%