Microstructures and properties of Ti-Nb alloys produced by powder metallurgy

Ti-Nb alloys were prepared by powder metallurgy. Their microstructures are detected by the XRD diffraction and are observed using an optical microscope. The mechanical properties are tested using a dynamic mechanical analysis (DMA) Q800 from TA Instruments in single cantilever mode and using a 100 KN MTS testing machine with control software. It has been found that the sintered Ti-Nb alloys possess the stable alpha and beta phases and the amount in beta phase increases with increasing Nb content. The water quenched Ti-35.4Nb alloy contains alpha '' and beta(M). The as-sintered alloy has higher yield stress and storage modulus than the water quenched Ti-35.4Nb alloy, which is resulted from the alpha phase with high modulus in the as-sintered alloy. The omega phase can be precipitated from beta(M) when the water quenched Ti-35.4Nb alloy is aged at 300 degrees C, causing the modulus to increase since omega phase has large modulus.