A review on WE43-metallic glass composites produced by friction stir processing: A new path towards biocompatible materials

In recent years, magnesium (Mg) alloys have gained considerable attention across diverse industries, including aerospace, automotive, electronics, and hydrogen storage, due to their low density, high specific strength, excellent damping capability, and favorable casting, machining, and recycling characteristics. Beyond structural applications, Mg alloys are regarded as favourable implant materials owing to their biodegradability, biocompatibility, and an elastic modulus close to that of cortical bone. Among Mg alloys, alloyed with rare-earth (RE) elements, particularly the WE series, exhibit enhanced formability, reduced basal texture intensity, superior high-temperature performance, and improved mechanical strength. Within this category, the WE43 alloy, based on the Mg-Y-Nd system, has become one of the most extensively studied and commercially successful alloys. However, the limited corrosion resistance of this alloy restricts its broader application. This review covers the microstructural evolution, mechanical performance, corrosion behaviour, and interfacial properties of WE43-based composites, with a special emphasis on metallic glass (MG) reinforcement strategies. The influence of various reinforcements and processing techniques on grain refinement, phase stability, and strengthening mechanisms, is carefully studied. The mechanisms for strengthening and stabilizing MG reinforcements in metallic matrices are next investigated, with a focus on interfacial bonding, improved load transfer, and thermal stability. Despite extensive research on MG-reinforced metal matrix composites, this study highlights a fundamental research gap; the integration of metallic glass into WE43 alloy, especially via FSP, has not yet been reported. This gap highlights a prospective and untapped avenue for developing enhanced biodegradable Mg composites with superior mechanical integrity and corrosion resistance.