Evolution of the microstructure and mechanical properties of Mg-matrix in situ composites during spark plasma sintering

Biomedical Mg-matrix in situ composites were fabricated from Mg and ZnO powder via ball mixing and spark plasma sintering. XRD analysis indicated that in situ reactions occurred during sintering process producing MgO, Zn and Mg-Zn intermetallic compounds. The formation of in situ products strongly contributed to the enhancement of the strength and the ductility of the fabricated composites compared with pure Mg. Specifically, the highest strength at 380MPa was observed in the Mg-20 wt-% ZnO composite, and the highest failure strain at 12.9% was achieved in the Mg-5 wt-% composite compared with the 156 MPa strength and the 10.2% failure strain of pure Mg. In addition, the strengths of as-produced composites are as double as that of cortical bones. With these superior mechanical properties, the fabricated composites are considered as very potential candidate for biomedical load-bearing applications.