Microstructure and mechanical properties of titanium (Grade 4) processed by high-pressure torsion

The influence of high-pressure torsion (HPT) at various temperatures on microstructure and mechanical properties of commercially pure (CP) titanium (Grade 4) has been studied using transmission electron microscopy and tensile tests. The temperature range of 70–450 °C for isothermal HPT processing has been used to fabricate nanocrystalline samples with diameter 20 mm under a pressure of 6 GPa. Using the new installation, we demonstrated that the ultimate tensile strength of CP Ti (Grade 4) after HPT processing achieves 1600 MPa as a result of significant grain refinement. At the same time, ductility of the HPT samples has been affected strongly by processing and annealing temperature.