Microstructure,Mechanical Properties And Hot Deformation Of Biomedical Beta Ti-12Mo-5x(Zr/Sn) Alloys

Medical β type titanium alloy has high strength, low density, good corrosion resistance and biocompatibility. It is wide attention that because of particularly low modulus of elasticity and does not contain toxic elements.Therefor it is an ideal biological medical materials. This paper prepared Ti-12Mo-5Zr(wt.%) and Ti-12Mo-5Sn(wt.%) alloys by water-cooled copper crucible vaccum induction melting furnace. The two cast alloys microstructure and the mechanical properties were studied. The effect of deformation parameters of the two flow stress and microstructure were studied. High temperature deformation mechanism of the two alloys were analysed; Using the results of hot compression to rolling and studied microstructure and properties and deformation behavior of plate.The results shows that The as-castmicrostructure of two alloys consist of acicular α phase and β phase.Ti-12Mo-5Zr alloy harder than the Ti-12Mo-5Sn alloy. The fracture strength and strain values of Ti-12Mo-5Zr alloy(1632.9MPa and 29.9%) is greater than the Ti-12Mo-5Sn alloy(1500.2MPa and 28.8%) in compression test. Fracture toughness value of Ti-12Mo-5Zr alloy(56.39 MPa?) is greater than Ti-12Mo-5Sn alloy(52.8 MPa?). Flexural strength and flexural displacement of the Ti-12Mo-5Zr alloy is greater than Ti-12Mo-5Sn alloy. The impact of Zr on strength and ductility of the alloy is stronger than Sn.High temperature hot compression simulation experiment shows that flow stress of two alloys decrease as the deformation temperature increase and strain rate decrease. Flow stress changes slowly when the deformation temperature is higher than 900℃. when the strain rate is 0.1s-1, the true stress-true strain curve will be "discontinuous yield" phenomenon which is related to the deformation process of dislocation motion. Alloys recrystallization is also growing significantly as deformation temperature increases or deformation rate decreases. Research shows that dynamic recrystallization mechanism of this two alloys is "discontinuous dynamic recrystallization" mechanism;Study results of 900 ℃ rolled plate showed that Texture present in the deformation of 70% of the plate.Ti-12Mo-5Zr alloy consists of α and β phase. But Ti-12Mo-5Sn alloy only contains β phase; Alloys prepared by heat treatment(900℃/1h) and quenching only consist single β phase. Lateral strength and elongation of Ti-12Mo-5Zr alloy respectively higher than the Ti-12Mo-5Sn alloy after rolling. It found that "double yield" phenomenon in the Ti-12Mo-5Sn alloy which is due to deformation caused by stress α" martensite transformation; Deformation of 45% alloy consist single β phase after heat treatment; Deformation behavior of tensile, compression and bending was studied, Research shows that initial deformation is slip, then tend to {332} <113> twinning;...