Features of the Structure Evolution and Phase Transformations During Annealing of the VT22 Titanium Alloy Depending on the Initial State

Studies have been carried out of the influence of annealing in the temperature range of 723–873 K on the evolution of the structural-phase state and mechanical properties of the VT22 titanium alloy depending on the method of its pretreatment (by all-round pressing and radial-shear rolling (RSR)). It has been shown that annealing of the alloy after all-round pressing leads to the development of phase transformations, formation of new grains with sizes less than 0.1 µm, slight grain growth, decrease in the degree of nonequilibrium grain boundaries, and recrystallization development. The preferential occurrence of certain processes, depending on the annealing temperature, causes a change in the mechanical properties of the alloy compared to the state after all-round pressing. It has been established that the RSR treatment of the VT22 alloy leads to a change in the nature of its structural-phase state evolution during annealing. The increase in the mechanical properties of the alloy in the case is due to the decomposition of the metastable β-phase with the formation of a fine-needle martensitic α phase and solid-solution strengthening. The coarsening of martensitic phase with increasing annealing temperature leads to a decrease in the mechanical properties of the alloy and an increase in the ductility.