Structure–property–biocompatibility interplay in heat-treated WE43 magnesium alloy

The WE43 magnesium alloy, composed of magnesium, yttrium, neodymium, and zirconium, has gained significant attention for biomedical applications on account of its favourable mechanical properties, biodegradability, and biocompatibility. However, its practical utility is hindered by rapid corrosion rates and wear susceptibility. This study systematically examines the microstructural features, mechanical properties, tribological behaviour, corrosion resistance, and cytotoxicity of WE43 in both as-cast (AC) and heat treated (HT) conditions.

In the current work, EBSD/KAM mapping revealed that heat treatment induced grain coarsening, increased high-angle grain boundaries (48 % vs. 10.6 % in AC), and reduced dislocation density, thereby improving crystalline quality. Tensile and hardness tests confirmed strength and hardness enhancements in the HT alloy (UTS: 189.6 MPa; hardness: 93 HV), but with reduced ductility. Tribological characterization demonstrated load- and velocity-dependent wear transitions, while hybrid predictive modelling captured wear behaviour with high accuracy (R² = 0.97). Electrochemical and immersion tests showed that HT specimens exhibited superior corrosion resistance (0.84 mm/year vs. 1.16 mm/year in AC), attributed to dissolution and redistribution of Mg-RE phases, leading to stable protective film formation. Cytotoxicity testing confirmed excellent biocompatibility, with cell viability consistently above 98 %.

Unlike prior works that mainly emphasize advanced manufacturing or surface modifications, this study establishes a comprehensive structure–property–biocompatibility framework for conventionally processed WE43. By integrating microstructural, mechanical, tribological, corrosion, and cytotoxicity analyses, it provides critical baseline insights and highlights the role of heat treatment in enhancing corrosion resistance, thereby offering a valuable benchmark for the future design of biodegradable magnesium implants.