Evaluating the Effect of Severe Plastic Deformation: High-Pressure Torsion and High-Pressure Sliding in Grade 2 Titanium

Abstract

This study investigates the effects of severe plastic deformation (SPD) techniques, particularly high-pressure torsion (HPT) and high-pressure sliding (HPS), on the microstructural evolution and mechanical properties of commercially pure (Grade 2) Ti. The experiments were conducted under pressures of 2, 5, and 6 GPa. For the crystallographic analyses, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used. Nanostructured Ti was obtained after processing by HPT and HPS, and the phase transformation from alpha (α) to omega (ω) phase was confirmed under pressures of 5 and 6 GPa. Vickers microhardness and tensile tests confirmed that HPT-processed samples exhibited increased strength under higher pressures, while the HPS process produced more homogenous material properties, along with a promising strength-to-ductility ratio. These findings indicate that the HPS process may offer better control over microstructure and mechanical performance, making it a promising technique to enhance the mechanical properties of pure Ti for biomedical applications.

Fig. 9 Comparison of yield strength vs. elongation to failure of data obtained in this study with those reported by Valiev et al. [67]. (online color)