Three-point bending behavior of surface composite Al2O3/Ni on bronze substrate produced by vacuum infiltration casting

Al2O3/Ni surface infiltrated composite layer is a protective surface layer. It was fabricated on bronze substrate through vacuum infiltration casting technique using Ni-based powder and Al2O3 powder with different content as raw materials. With an appropriate choice of processing condition, a compact infiltrated layer is achievable as conformed through SEM observation. The infiltrated layer consists of surface composite layer and transition layer, and the thickness of transition layer decreases with increasing content of Al2O3. Metallurgical fusion formed at the interface between the surface infiltrated composite layer and substrate. Three-point bending tests were carried to investigate the mechanical and bonding properties of the surface infiltrated layer. It was found that load-holding circumstance appeared on the load–displacement curve of specimen with surface infiltrated layer comparing with that of the substrate. The peak load reduces with increasing content of Al2O3. The fracture extended to the substrate for specimen with Al2O3 content less than 20 (wt%). The fracture direction of specimen more than 30% with Al2O3 (wt%) is along with the interface of the surface composite and the substrate because of the thinner transition layer.