The Zr-doped Mg-Zn-Ca bulk metallic glasses with high compressive strength, distinct plasticity and good corrosion resistance

Abstract

This work demonstrates that the Zr-doped Mg-Zn-Ca bulk metallic glasses (BMGs) with no toxic or allergenic substances exhibit good corrosion resistance, high compressive fracture strength together with distinct plasticity. The Mg-based BMGs containing Zr element up to 1.5 at.% show slightly higher thermal stability. The addition of Zr effectively slows down the degradation rate of the alloy from a rather fast level of the Mg-Zn-Ca base alloys. When Mg-based BMGs are treated with Zr element, their corrosion resistance in simulated body fluids (SBF) is enhanced by promoting the generation of a Zn²⁺-enriched protective coating on the alloy surfaces. The 1.5 at.% Zr glassy alloy displays significantly improved compressive fracture strength of 810 MPa. More importantly, the distinct plastic deformation region is observed in the compressive curves for the Zr-doped BMGs. Moreover, the formation of plenty of shear bands on the outer surface for the 1.5 at.% Zr alloy indicates that minor alloying Zr improves the plasticity of the Mg-based BMGs. The success in synthesizing toxic elements-free Mg-based BMGs with excellent combination of high fracture strength, distinct plasticity, desirable resistance to corrosion is encouraging for the exploitation of new plastic Mg-based biomaterials for high performance biodegradable implants.