Effect of cryogenic treatment on mechanical, tribological, biocompatibility and biodegradability behaviour of AZ31-based hybrid composites

Materials intended for orthopedic applications must possess high strength, low density, excellent biocompatibility, and superior wear resistance. Mg and its alloys are most promising candidates for biomedical applications due to their unique properties. However, the insufficient mechanical and corrosion properties of pure Mg have limited its practical use. This work aims to investigate the mechanical, tribological, biocompatibility, and biodegradability behaviours of AZ31 Mg alloy reinforced with 10 wt-% ZrO2 and 2 wt-% seashell powder (SSP), with a focus on the effects of cryogenic treatment. The AZ31 composite was fabricated using the stir casting method. All the tests were conducted for pure AZ31 Mg, the prepared composite, and the cryotreated composite samples and the results were compared. SEM results confirmed a homogeneous distribution of the reinforcement particles. The physical and mechanical properties were significantly enhanced in the cryotreated composite compared to the other samples. Wear tests carried out using a pin-on-disc tribometer revealed that the wear rate (WR) and coefficient of friction (COF) were considerably lower for the cryotreated samples. Biocompatibility tests show that the cryotreated composites did not exhibit any adverse reactions on MG63 cells. Furthermore, cryogenic treatment improved the corrosion resistance of the composite relative to the untreated samples.