Effect of cooling rate on microstructure and corrosion behavior of biodegradable Mg-5Zn-1Y-0.1Ca alloy in simulated body fluid

In the present study, the effect of different cooling rate on microstructure and corrosion behavior of Mg-5Zn-1Y-0.1Ca biomedical alloy are investigated. Microstructure observations using optical and scanning electron microscopes showed that the alloy contains α-Mg as the matrix, and Mg3YZn6 and Ca2Mg6Zn3 intermetallic precipitations, having lamellar morphology formed mostly at the grain boundaries. Also microstructure results showed that with increasing cooling rate, the continuity of precipitations increase in grain boundary and inter dendritic zones. The polarization test, as well as the immersion result, confirmed that increasing the cooling rate does not always improve the corrosion properties, and it seems there is an optimal cooling rate resulting in minimum corrosion rate.
Abstract:In the present study, the effect of different cooling rate on microstructure and corrosion behavior of Mg-5Zn-1Y-0.1Ca biomedical alloy are investigated. Microstructure observations using optical and scanning electron microscopes showed that the alloy contains α-Mg as the matrix, and Mg3YZn6 and Ca2Mg6Zn3 intermetallic precipitations, having lamellar morphology formed mostly at the grain boundaries. Also mi