Structural and phase transformations in a quenched two-phase titanium alloy upon cold deformation and subsequent annealing

Abstract

Methods of X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and differential scanning calorimetry have been used to study the formation of the structure and phase composition upon the cold rolling of rodlike semi-finished products of the VT16 alloy quenched for martensite (Tq = Tpt − 10 K). It has been established that, with an increasing degree of elongation caused by rolling in the range under investigation, a more complete deformation-induced transformation occurs according to the scheme α″ → (α′ + βa) with the formation of a βa solid solution with an anomalously large lattice parameter because of the development of accommodation processes due to the difference in the specific volumes of the initial (α″) and arising (α′) martensitic phases. A correlation between the phase composition and the microhardness and elastic characteristics has been established. The temperature intervals of the occurrence of the processes of solid-solution decomposition have been determined upon the continuous heating in the quenched and cold-rolled states.