Effects of nano-Y_2O_3 addition on the microstructure evolution and tensile properties of a near-α titanium alloy

摘要

Reactive element oxide (REO) can significantly refine cast microstructure and improve mechanical properties. In this study, Y2O3 nanoparticles (similar to 30 nm) were added into a near-alpha titanium alloy by vacuum arc melting furnace. The nano-Y2O3 grew into dendritic and near-equiaxed Y2O3 crystals because of segregation in the solution. Apart from refined beta grain size, Y2O3 particles also coarsened the needle alpha lamellar (alpha(s)) by providing supernumerary nucleation sites for alpha(s) in subsequent beta -alpha(s) transformation. Owing to the load transfer mechanisms, ultimate tensile strength and yield strength were evidently enhanced either at room or elevated temperature. The theoretical strengthening model of Y2O3ear-alpha-Ti alloy matched the experimental values well.