In-situ investigation of phase transformations in ultra-fine grained Ti15Mo alloy

A metastable β solution treated Ti15Mo alloy was deformed by high pressure torsion (HPT) resulting in a severely microstructure with density of lattice defects. In order to gain insight into the kinetics phase transformations, both non-deformed and HPT-deformed materials were studied in-situ during linear heating; evolution investigated using energy synchrotron X-ray diffraction (HEXRD) complemented measurement electrical resistance. It shown that material dissolution ω is followed precipitation α heating. contrast, nucleation shifted lower temperatures, coexistence all three β, ω, phases at ~550 °C. Moreover, samples, growth particles accelerated due dislocations grain boundaries. Post-mortem observations selected samples revealed after heating up 650 °C remains ultra-fine grained equiaxed grains phase.