Effects of Strontium addition on microstructure, mechanical properties, corrosion properties and cytotoxicity of Mg–1Zn–1Mn alloy

Mg–1Zn–1Mn (wt%) alloy and Mg–1Zn–1Mn–xSr (wt%, x = 0.1, 0.25, 0.5, 1) alloy as candidates for degradable biomaterials were prepared by casting and extrusion methods. The effect of Sr addition on microstructure, mechanical properties, corrosion resistance and cytotoxicity of Mg–Zn–Mn alloy was investigated. The results showed that Mg–1Zn–1Mn alloy mainly consisted of α-Mg matrix phase while Mg11Zn4Sr3 phase was formed in Mg–1Zn–1Mn–0.25Sr, Mg–1Zn–1Mn–0.5Sr and Mg–1Zn–1Mn–1Sr alloy. After adding Sr, the highest tensile strength of Mg–1Zn–1Mn–1Sr alloy was 280 MPa, but its elongation dropped to 7%. Mg–1Zn–1Mn–0.25Sr alloy exhibited better corrosion resistance in immersion tests, with hydrogen evolution rate of 0.42 mm/year, weight loss rate of 0.72 mm/year, and pH value of 9.0. The cytotoxicity tests indicated that both Mg–1Zn–1Mn and Mg–1Zn–1Mn–0.25Sr alloys were non-toxic against L-929 cells and the highest relative growth rate of Mg–Zn–Mn–0.25Sr extracts group was 102%.