Microstructure and wear property of As-cast Mg–2-wt.%-Sn alloys after different heat treatment processes

Abstract

The developments of biodegradable materials for orthopaedic implants has been progressing rapidly for decades. Biodegradable implants can eliminate the need for a second surgery and avoid the possible risks of retained metallic implants, such as corrosion or strength weakening. Magnesium (Mg) alloy is one of the potential materials for biodegradable implants because of its good biocompatibility and biodegradability. In this study, the microstructures and mechanical properties, especially the wear behavior and friction characteristics of Mg–Sn alloys, were investigated. Mg–Sn alloys fabricated by the ingot casting method were applied to different heat treatments, and then subjected to the pin-on-disc wear test. Experimental results showed that the Mg–Sn alloy processed by solution heat treatment (SHT) at 520 ℃ and quenching had the best wear resistance and lowest coefficient of friction (COF). The decrease in the amount of hard precipitate Mg 2 Sn and the solid-solution strengthening induced by the excess Sn atoms in the Mg matrix were the main causes of the enhancement of the wear properties of the Mg–Sn alloy upon SHT, compared with as-cast Mg–Sn alloy and the Mg–Sn alloys made by other heat treatments.