Magnesium/fish bone derived hydroxyapatite composites by friction stir processing: studies on mechanical behaviour and corrosion resistance

Magnesium (Mg)-based biomaterials are widely investigated for degradable implant applications. Developing Mg-based composites is one of the strategies adopted to increase the bioactivity and to reduce the degradation rate of Mg. In the present study, hydroxyapatite (fHA) has been produced from fish bones and incorporated into pure Mg sheets by friction stir processing (FSP). Microstructures of the composites clearly revealed the grain refinement in the stir zone up to 10m from the starting size of 2000m. Measurements of microhardness also indicated the effect of a smaller grain size and the presence of fHA on increasing the hardness in composites. Interestingly from the tensile tests, mechanical properties, such as yield strength and ultimate tensile strengths were measured as they decreased for the composite due to the presence of fHA particles. However, the observed % elongation of the composite was similar to that of a natural bone. From the electrochemical tests, the composite exhibited an enhanced corrosion performance. From the results, it can be concluded that the cost-effective Mg-fHA composites can be developed by FSP for degradable scaffold applications in biomedical fields.