effects of heat treatment on the microstructural stability, mechanical properties and degradability of as-cast mg–1y and mg–1ca alloys: a comparative study

Y and ca are two alloying elements which are being extensively used to enhance different properties and address the challenges of biodegradable mg alloys. in this study, the efficiency of y and ca for improving microstructure stability during high-temperature solution treatment was assessed and compared by studying the microstructure as well as the mechanical and degradation properties of mg–1wt%y and mg–1wt%ca alloys. x-ray diffraction and field emission scanning electron microscopy studies demonstrated presence of mg24y5 and mg2ca particles in mg–1y and mg–1ca alloys, respectively. in addition, the mg–1y alloy witnessed a significantly higher level of grain growth in comparison with mg–1ca alloy. the results of shear punch test and hardness experiments demonstrated greater mechanical strength perseverance of ca-incorporated alloy as the result of the presence of mg2ca phase as well as the finer microstructure. accordingly, it can be pointed out that ca is a more suitable element for stabilizing the microstructure of mg-based alloys at high temperatures in comparison with y. on the other hand, the hydrogen evolution test in phosphate-buffer saline (pbs) solution showed that y-incorporated alloy possessed higher corrosion resistance. also, reducing the micro-galvanic corrosion effects by long-term annealing in high temperatures can be an effective approach to enhance the degradability of both alloys, where the best corrosion resistance was observed in annealed mg–1y alloy.