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 a-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%.