Harmonizing Microstructures and Enhancing Mechanical Resilience: Novel Powder Metallurgy Approach for Zn-Mg Alloys

TL;DR

This paper introduces a novel powder metallurgy method to create zinc-magnesium alloys with a pseudo-harmonic microstructure, significantly improving their mechanical strength for biomedical implant use.

Contribution

It presents a new fabrication process combining mechanical alloying, spark plasma sintering, and hot extrusion to engineer zinc alloys with enhanced mechanical properties.

Findings

Tensile strength reached 333 MPa after hot extrusion.

Mg2Zn11 phase contributed to increased strength.

Oxide shells negatively impacted mechanical performance.

Abstract

Zinc alloys are recognised for their excellent biocompatibility and favourable corrosion rates, making them suitable for bioabsorbable implants. However, their mechanical properties necessitate improvement to fulfil the rigorous requirements of biomedical applications. This research focuses on engineering pseudo-harmonic structures within zinc alloys through a comprehensive method combining mechanical alloying, spark plasma sintering, and hot extrusion techniques. This fabrication process results in a composite material characterised by a soft core surrounded by a continuous, three-dimensional, ultrafine-grained hard shell. The experiment involved blending pure zinc with Zn-1Mg alloy powder, leading to the formation of both ductile zinc and fine-grained Zn-1Mg regions. While the Mg2Zn11 intermetallic phase was found to enhance the alloy's mechanical strength, the presence of oxide shells adversely affected the material's properties. The elimination of these shells via hot extrusion markedly improved the alloy's tensile strength, reaching an average value of tensile strength of 333 MPa. This study provides significant insights into the material engineering of zinc-based alloys for biodegradable implant applications, demonstrating a viable approach to optimising their mechanical performance.