Effect of Casting Method of AZ91 D Magnesium Alloy on the Degradation Behaviour in Simulated Body Fluid

Magnesium-based alloys as biodegradable orthopedic implants have been successful for their high degradation rates in the physiological environment and the consequent loss in the mechanical integrity. Casting method used in production of magnesium-based alloys influences the microstructure of implants due to cooling conditions. In this study, the effects of casting method (permanent mold casting and sand mold casting) on the degradation of AZ91D magnesium alloy in Hank's simulated body fluid at 36.5 +/- 0.5 degrees C have been investigated using immersion technique of cylindrical specimens. The specimens were subjected to simulated body fluid for 8 h and 24 h. The results have shown that the cooling rate from melt and grain size have great influence on the degradation rate of magnesium alloy.