Microstructures and mechanical properties of Ti-6Al-7Nb processed by high-pressure torsion

Ti-6Al-7Nb was deformed by high-pressure torsion to improve the mechanical properties of the alloy. high-pressure torsion was conducted at room temperature under pressures of 2 and 6 GPa for disk-shaped specimens. Microstructure was characterized by transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). Mechanical properties were evaluated by tensile test and Vickers microhardness measurement. The grain size was refined to about 100 nm after high-pressure torsion processing under 6 GPa through 5 revolutions. Hardness increased with straining by high-pressure torsion and the values after high-pressure torsion processing under 6 GPa were higher than those under 2 GPa. Tensile strength after high-pressure torsion processing of all conditions was higher than that before high-pressure torsion processing. It was found that microstructure and mechanical properties were improved by high-pressure torsion processing. (C) 2014 Published by Elsevier Ltd.