METAL MATRIX COMPOSITES FOR ORTHOPAEDIC APPLICATION

Abstract

Orthopaedic implant materials are more focused on metal composites due to their enhanced mechanical properties compared to polymers and ceramics. Some metallic materials have good mechanical properties, but after implantation, they create toxicity inside the human body. Due to this reason, new metal composites have become a trending research topic in bio-implantation fields. Based on magnesium (Mg), whose density and Young's modulus are closer to human bone, composite scaffolds are prepared through a powder metallurgy process where zinc (Zn) and strontium (Sr) have been added to control degradation rate and pore size. Keeping Zn concentration constant, Sr concentration varied from 0.5 to 2 wt%, where the composite scaffold with the highest Sr concentration (sample C) shows the most improved mechanical and biocompatibility characteristics with the minimum corrosion rate. All composite scaffolds have interconnected and isolated pores with pore sizes of 127–279 µm. The addition of Zn and Sr reduces the surface roughness, where sample C has a minimal 0.11 µm value. With decreasing porosity, the mechanical properties have improved in terms of the highest hardness and compressive strength, 102 HV and 24 MPa, respectively. In vitro immersion tests revealed that sample C has the lowest weight loss value of 6.65g and a corrosion rate of 2.194 mm/y compared to the other two composite scaffolds. Due to improved mechanical and corrosion resistance characteristics and 2.7% hemocompatibility, sample C is more recommended and suited for orthopaedic applications.