Study On Mechanical Properties And Corrosion Resistance Of Mg-6%Zn-10%Ca Alloy

Magnesium alloy has low density, good damping property, low elastic modulus, bioc- ompatibility. It had wide application prospect in industry and medical field. However, the lower mechanical property and fast corrosion rate limit its application. This magnesium alloy what the pure magnesium was doped with zinc and calcium was considered the most potential in the field of medicine and industry.The microstructure of as-cast and heated alloy was observed by using scanning electron microscopy(SEM), the phase constitution of alloy was analysed by XRD. The mechanical properties were measured by HX-1000TM/LCD micro hardness tester and electronic tensile testing machine. The corrosion behavior of the alloys in both 3.5%NaCl solution and SBF solution was studied by immersion test and electro-chemical testing method. The corroded surface morphology of the alloys was observed by SEM, the composition and constitution of alloy corroded products were analysed by energy dispersion spectrum(EDS) and X-ray diffraction(XRD).The research shows that the as-cast Mg-10Ca-6Zn alloy was composed of α-Mg phase、Ca2Mg6Zn3 phase and Mg7Zn3 phase. The heated alloy had new phases that were MgZn2 phase and Mg2 Ca phase and the Mg7Zn3 phase was disappear. The mechanical properties of the Mg-10Ca-6Zn alloy were improved after heating treatment. However, with the increasing of heating treatment temperature and time, there are a large number of second phase on the grain boundary, and the mechanical properties of the Mg-10Ca-6Zn alloy were decreased. The segregation of the Mg-10Ca-6Zn alloy,s microstructure and composition was eliminated by heating treatment, and the distribution of the second phase and grain were more uniform, which improved the corrosion resistance of the alloy.