The effect of adding alumina particles on niobium-zirconium alloy mechanical properties

Niobium–zirconium (Nb–Zr) alloys are emerging as promising candidates for biomedical implants owing to their excellent corrosion resistance, biocompatibility, and lower modulus of elasticity compared with those of common metallic biomaterials. However, their mechanical strength and wear resistance need to be improved for load-bearing purposes. In the present work, the Nb-1 wt% Zr matrix composites having different alumina (Al₂O₃) contents of 0.5–6 wt%, prepared by the powder metallurgy process, have been synthesized at 1200 °C for 6 hours and examined systematically to determine their effect on porosity, hardness, compressive strength, elastic modulus, and dry sliding wear behavior. The porosity decreased initially until the Al₂O₃ reached 0.5 wt%, then increased slowly at higher contents. The best mechanical properties were obtained by 6 wt% Al₂O₃, where the compressive strength was enhanced from 134 to 234 MPa (74.6%), while the hardness increased by more than 90%, and the wear rate decreased by up to 92.5% at a load of 25 N. Meanwhile, the elastic modulus reduced from 70.6 GPa to 22.2 GPa (69% reduction) to be closer to that of cortical bone and to limit the stress-shielding effect at the same time. These results indicate that the controlled Al₂O₃ reinforcement can effectively enhance the mechanical and tribological performance of Nb– Zr alloys while demonstrating biomechanical compatibility, making them prospective candidates for next-generation load-bearing surgical implants.