Effects of solution treatment on yield ratio and biocorrosion behaviour of as-extruded Mg–2·7Nd–0·2Zn–0·4Zr alloy for cardiovascular stent application

Abstract

Biodegradable magnesium alloy with proper yield strength, high ultimate strength and elongation is a potential candidate for cardiovascular stent. Nevertheless, magnesium alloy with high ultimate tensile strength always exhibits high yield strength, which is not suitable for the plastic deformation of cardiovascular stent during implantation. Solution treatment was conducted on the as extruded Mg–2·7Nd–0·2Zn–0·4Zr alloy in order to reduce the high yield ratio, and the biocorrosion behaviour of the alloy was also evaluated in artificial plasma. The results show that the grains of the alloy grow, and the second phase reduces with increasing solution treatment temperature. The yield strength decreases gradually, and the ultimate tensile strength still keeps a high level due to the remarkable workhardening. The yield ratio of the alloy reduces from 92 to 57%. The corrosion resistance of the alloy after solution treatment is improved slightly when the temperature is <475°C.