Morphological, microstructural, mechanical, and electrochemical optimization of a novel Mg–2Ca–1Mn–1 Sr alloy by P ion implantation for orthopedic implants

Abstract

This study investigates the influence of phosphorous (P) ion implantation on the morphological, microstructural, mechanical, and electrochemical properties of a novel bioresorbable Mg–2Ca–1Mn–1 Sr (XMJ211) quaternary alloy in simulated body fluid (SBF) post-implantation for potential orthopedic implants. The novelty lies in both the unique alloy composition and systematically optimizing the alloy's performance through P ion implantation at varying fluences. XRD analysis revealed the increased volume fractions of secondary binary phases, such as Mg3P2, and a fractional decrease in grain size from approximately 71 µm to 39 µm with gradually increased P implantation. Mechanical hardness improved from approximately 60 HV to 75 HV with P addition due to grain refinement and increased second-phase binary particles. The EIS analysis confirmed an improvement in the bio-corrosion resistance of the alloy from 48 kΩ to 87 kΩ as P addition increased up to fluence 4, with diminishing effects at higher fluences. The study results successfully demonstrate a balance between the mechanical and electrochemical properties of the alloy with moderate amounts of P addition, positioning it as a promising bioresorbable biomaterial for orthopedic implants and eliminating the need for secondary implant removal surgery post-patient recovery. This research bridges the knowledge gap in the literature and introduces a novel approach to optimizing the performance of Mg-based alloys for biomedical applications.