Influences of the Ag content on microstructures and properties of Zn–3Mg–xAg alloy by spark plasma sintering

In order to improve the comprehensive mechanical properties of Zn–3Mg alloy to meet application requirements of medical metal implants, spark plasma sintering (SPS) was adopted to prepare Zn–3Mg–xAg alloy (x = 0, 1, 1.5, 2, 2.5). Electron backscatter diffraction (EBSD)observation was adopted to investigate the growth twins in Zn–3Mg–xAg alloy, and then influences of Ag element on compactness, microstructure, tensile and compression properties of the zinc-based alloy were studied. Results showed that the length of growth twins first increased, then decreased with the increase of Ag element. Growth twins improved the ductility of alloy by turning the hard oriented grains into soft ones. The Zn–3Mg–1.5Ag alloy showed the best comprehensive mechanical properties due to the joint effect of solid solution strengthening, precipitation phase strengthening, fine grain strengthening and defect weakening. The tensile strength of Zn–3Mg–1.5Ag was 273.8 ± 16.9 MPa, which was 2.5 and 1.6 times that of Zn and Zn–3Mg respectively; the elongation was 10.67 ± 0.77%, which was 3.6 and 2.6 times that of Zn and Zn–3Mg respectively. Compressive strength of Zn–3Mg–1.5Ag was 543.7 ± 38.1 MPa, which was 3.8 times that of Zn; fracture strain of Zn–3Mg–1.5Ag was 20.49 ± 1.21%, which was 2 and 1.5 times of pure Zn and Zn–3Mg alloy.