Annealing behavior of coarse-grained titanium deformed by cold rolling

This work describes the annealing behavior of coarse-grained titanium deformed by cold rolling. A longitudinal section of a high-purity coarse-grained titanium ingot obtained by double electron beam melting (EBM) was cold rolled to thickness reductions varying from 10 to 70%. Vacuum annealing was performed at 500, 700 and 800 °C for 1 h (α-phase field). Microstructural characterization was performed in both cold rolled and annealed specimens using light optical microscopy (LOM), scanning electron microscopy (SEM), electron backscattered diffraction (EBSD) and Vickers microhardness testing. Orientation effects associated with the coarse initial grain structure of oligocrystalline titanium were observed during annealing. In certain regions the microstructure of annealed titanium consists of alternating bands of recrystallized grains with local variations in grain size and texture and a few elongated areas marking the presence of individual grains softened by recovery.