Effects of Yttrium Content on Microstructural and Properties of Biodegradable Mg–2.0Zn–0.3Mn–2.0Al Alloys

Abstract

Biodegradable magnesium (Mg) alloys are a promising implant material due to their biomechanical compatibility and in vivo degradability. However, their rapid in vivo corrosion rate limits their use. This study investigates the influence of yttrium (Y) content (0–2.5 wt%) on the microstructure, tensile mechanical properties, and corrosion mechanism of Mg–2.0Zn–0.3Mn–2.0Al–xY alloys. Microstructural analysis reveals that the addition of Y refines grain size and promotes the formation of secondary phases, mainly Al₂Y and (Al,Zn)₁₁Y₃, and solution treatment induces fragmentation and spheroidization of rod-like (Al,Zn)₁₁Y₃ into Al₂Y. The tensile mechanical properties peak at 1.5 wt% Y, while the corrosion resistance in simulated body fluid is optimal at 1.0 wt% Y, revealing a trade-off between strength and degradation performance. The results of this study establish a clear relationship between processing and microstructural properties, providing guidance for the design of advanced biodegradable Mg alloys.