Heterogeneous amorphous/crystalline ZnZrCu biodegradable alloys with synergistic strength–plasticity prepared by mechanical alloying and laser powder bed fusion

Abstract

ABSTRACT Amorphous Zn-based alloys have shown considerable potential for implant applications owing to the impressive strength. However, they inevitably fall into strength–plasticity trade-off dilemma due to shear bands softening. In this work, a novel and feasible route of mechanical alloying (MA) and laser powder bed fusion (LPBF) was first developed for manufacturing heterostructured ZnZrCu alloys. The results showed that MA destabilised atomic periodicity of Zn/Zr powders and induced amorphization. Furthermore, increasing Cu content enhanced amorphization ability and in-situ synthesised ϵ-phases, endowing ZnZrCu powders with heterostructure. During LPBF, the fast-melting kinetics and highly localised nature restricted devitrification and promoted the uniform distribution of ϵ-phases, constructing heterogeneous amorphous/crystalline ZnZrCu alloys. Consequently, ZnZrCu alloys exhibited good strength–plasticity synergy attributed to extra strain-hardening and hampering premature failure of shear bands. This study not only provides a feasible route to prepare biodegradable Zn-based alloys with strength–plasticity synergy but also sheds light on the design and manufacture of cutting-edge amorphous alloys.