New Ti/β-Ti alloy laminated composite processed by powder metallurgy: Microstructural evolution and mechanical property

Pure Ti shows promising performance for biomedical applications, but its strength needs to be greatly improved when used as heavy-load implants. In this work, β-Ti alloy was used as the reinforced layer to prepare Ti/β-Ti alloy laminated composite through Spark Plasma Sintering (SPS) with hot/cold rolling and partial recrystallization annealing. The microstructural evolution of Ti layer, β-Ti alloy layer and the interface between them during the fabrication process was investigated. The results showed the composite comprises alternating recrystallized Ti layer, β-Ti alloy layer with deformed microstructure, and α+β dual phase interface layer containing submicron sized rod-like or granular α phase. Besides, the deformation behavior and mechanical properties of the Ti/β-Ti alloy laminate composite were studied. The Ti/β-Ti alloy laminate composite after partial recrystallization annealing shows a good match of high strength and good ductility (tensile strength: 832 MPa and uniform elongation: 20%), owing to the co-work of the diffusion interface layer and the constraint effect. The α+β dual phase layer has an important effect on weakening the deformation incompatibility between Ti layer and β-Ti alloy layer and preventing crack propagation during the tensile deformation.