Surface Modification of Mg Alloys: An Insight into Friction Stir-Based Techniques

Many biomaterials for long-term usage in the body have been developed recently. Biomaterial manufacture and utilisation should prioritise medicinal purposes. After biological prostheses are implanted, human tissues may react to the prosthesis. These responses influence implant biocompatibility and success. Implant applications depend on biomaterial mechanical characteristics. Biomaterial fatigue resistance, elongation, strength, and deformability are crucial for load-bearing hard-tissue implantation. Due to these characteristics, researchers have developed scaffolding, stent, and hard tissue implantation biomaterials for orthopaedic implants. Magnesium, a biocompatible, low Young’s modulus material, might replace bone. In pH 7.4-7.6 applications, it corrodes quickly. Thus, bone tissue may not heal before the implants’ mechanical integrity is damaged. However, magnesium’s slower degradability reduces the release of magnesium ions (Mg²⁺), hydrogen ions (H₂), and hydroxyl radicals (OH^-), giving the body time to recover from biodegradation. Alloying, metal-matrix composites, and surface modification may slow magnesium biodegradation. However, the surface composite alteration has benefits. Friction stir-based methods like friction stir processing may be effective for producing magnesium matrix surface composites to alter surface characteristics. This chapter focuses largely on discussing different friction stir-based processes used to modify the surface of the magnesium alloy. These methods may prolong implant usage and retention in humans.