Influence of reinforcements in friction stir processed magnesium alloys: insight in medical applications

Abstract

Magnesium alloy shows great potential in medical devices such as wound closing devices, bone grafts and cardiovascular stents owing to its mechanical and biodegradable properties. However, its clinical applications are limited due to its biocompatibility and rapid corrosion. Since material corrosion and biocompatibility can be categorized under surface properties of biomaterials, this study employed a surface modification method to fabricate new alloys. Reinforcement of magnesium alloys with powders have engineered a new type of material regarded as metal matrix composites. Friction Stir processing method was used in this study to fabricate AZ31 magnesium alloy. The Mg alloys were reinforced with four different powders (i.e. Fly Ash, Palm Kernel Shell Ash, Ti-6Al-4V and 304 Stainless steel powders) to try to improve the acute corrosion resistance and also other mechanical properties such as hardness, tensile property and wear performance of the fabricated composites. The result shows that particle reinforcement of magnesium alloy has much influence on the corrosion rate and wear behavior when compared with the unreinforced AZ31 Magnesium alloy. 304 stainless steel serves as the best reinforcement among the reinforcements used in this study, offering the highest corrosion resistance of 0.2020 mm/year, good wear resistance and higher tensile strength of 454.18 MPa. Therefore, this study may offer insight on obtaining both corrosion resistance and biocompatibility at the same time on the magnesium alloy, which may extend their potential applications in biomaterials and biomedical devices.