Novel combinatorial microstructures in Ti-6Al-4V alloy achieved by an electric-current-pulse treatment

An electric-current-pulse (ECP) treatment was employed to rapidly heat a dogbone-shaped Ti-6Al-4V sheet. After the treatment, the alloy was modified from a single micrometer-sized structure to a shape-associated combinatorial counterpart. Coexisting with the original equiaxed coarse-grained α-Ti and the intergranular β-Ti, two kinds of novel ultrafine structures, nanometer-sized lamellar twins of β-Ti martensites and refined bimodal structure have been produced in the different parts of the bulk sample. Formation of the novel microstructures during the ECP treatment was systematically investigated. This work demonstrated that the ECP rapid heating treatment is a promising method to tailor the microstructures of the metallic alloys basically by designing the shape-associated distribution of the current density and offer a new possibility for improving the conventional alloys. (orig.)