Refinement of Microstructure and Mechanical Properties of Titanium Processed by Twist Extrusion and Subsequent Rolling

Abstract

Microstructure and mechanical properties as well as thermal stability of commercially pure titanium VT1-0 subjected to severe plastic deformation by twist extrusion (TE) were studied before and after low-temperature annealing and cold rolling. TE leads to a refinement of structural fragments to sizes of less than 1 μm, enhancement of strength, and the appearance of strong anisotropy of mechanical properties. Subsequent low-temperature annealing increases plasticity of the deformed titanium, retaining its enhanced strength. A combined treatment (TE and rolling) results in an additional refinement of the microstructure, which remains thermally stable to 300-350°C, and changes the anisotropy of mechanical properties.