Mechanical properties and corrosion behavior of Mg-Gd-Ca-Zr alloys for medical applications.

Abstract Magnesium alloys are promising candidates for biomedical applications. In this work, influences of composition and heat treatment on the microstructure, the mechanical properties and the corrosion behavior of Mg–Gd–Ca–Zr alloys as potential biomedical implant candidates were investigated. Mg 5 Gd phase was observed at the grain boundaries of Mg–10Gd– x Ca–0.5Zr ( x =0, 0.3, 1.2 wt%) alloys. Increase in the Ca content led to the formation of additional Mg 2 Ca phase. The Ca additions increased both the compressive and the tensile yield strengths, but reduced the ductility and the corrosion resistance in cell culture medium. After solution heat treatment, the Mg 5 Gd particles dissolved in the Mg matrix. The compressive strength decreased, while the corrosion resistance improved in the solution treated alloys. After ageing at 200 °C, metastable β′ phase formed on prismatic planes and a new type of basal precipitates have been observed, which improved the compressive and tensile ultimate strength, but decreased the ductility.