Effect of cold rolling and annealing on the microstructure evolution of titanium alloy grade 2

Abstract

In the present work, we studied the influence of cold rolling and annealing on the microstructure evolution and hardness of Titanium alloy grade 2. Three different samples were prepared for cold rolling at 10%, 20% and 40% reduction. After cold rolling, heat treatment was carried out in a tube furnace at 575°C (below β transus temperature) for 20 min in an inert argon gas medium. Cold rolled samples were compared with the as-received samples. Microstructural observations show that in addition to elongation of grains along the rolling direction, cold rolling refined the grain size. Elongation in grains increased with increase in degree of cold rolling. Subsequent heat treatment led to the formation of new equiaxed grains in the deformed structure. The number and area fraction of the new grains increased with increasing degree of deformation for the given heat treatment condition. Hardness increased with increasing degree of cold rolling and decreased after the heat treatment. Inter-grain distance was calculated to estimate the spatial distribution of recrystallized grains after heat treatment with varying degree of deformation.