A High-Strength and Biodegradable Zn–Mg Alloy with Refined Ternary Eutectic Structure Processed by ECAP

Abstract

In this study, the microstructure, mechanical properties and corrosion behaviors of a Zn–1.6Mg (wt%) alloy during multi-pass rotary die equal channel angle pressing (RD-ECAP) processing at 150 °C were systematically investigated. The results indicated that a Zn + Mg2Zn11 + MgZn2 ternary eutectic structure was formed in as-cast Zn–Mg alloy. After ECAP, the primary Zn matrix turned to fine dynamic recrystallization (DRX) grains, and the network-shaped eutectic structure was crushed into fine particles and blended with DRX grains. Owing to the refined microstructure, dispersed eutectic structure and dynamically precipitated precipitates, the 8p-ECAP alloy possessed the optimal mechanical properties with ultimate tensile strength of 474 MPa and elongation of 7%. Moreover, the electrochemical results showed that the ECAP alloys exhibited similar corrosion rates with that of as-cast alloys in simulated body fluid, which suggests that a high-strength Zn–Mg alloy was successfully developed without sacrifice of the corrosion resistance.