Effect of high pressure torsion on the aging kinetics of ?-titanium Ti-15Mo alloy

This paper focuses on the study of the aging kinetics of the b-titanium Ti-15Mo alloy prepared by high pressure torsion. The experimental methods of differential scanning calorimetry and transmission electron microscopy were used for structural investigations. It was established that during aging at 500 and 550 degC, in the ultrafine-grained (UFG) alloy, the precipitating a-particles have mostly equiaxed morphology, in contrast to the needle-like and lens one in the coarse-grained (CG) alloy. There have been identified differences in the aging kinetics of the Ti-15Mo alloy in the UFG state identified by a decrease in microhardness within the first 30 minutes of heating, as opposed to the CG alloy coarsening. The influence of morphological features of the alloy microstructure on the strengthening effect after aging is discussed.