Effect of equal channel angular pressing on the structure and mechanical properties of new Ti–10Mo–8Nb–6Zr β-Ti alloy

Abstract

This paper presents comparative studies of the structural and mechanical properties of the new Ti–10Mo–8Nb–6Zr β-Ti alloy subjected to traditional cold rotary forging and equal channel angular pressing (ECAP) at 250 °C. The main phase in the initial hardened state after forging and ECAP is the BCC β phase. A broadening of the β phase X-ray lines and TEM data indicate a reduction in the structure and an increase in the concentration of lattice defects after deformation treatments. In the initial state, the alloy has an ultimate tensile strength of about 700 MPa, offset yield strength of 450 MPa and elongation at break of ~30 %. As a result of forging, the ultimate tensile strength and offset yield strength of the alloy increase to 1230 and 950 MPa, and after ECAP – to 1280 and 1270 MPa, respectively. At the same time, the elongation is reduced to 6 % after ECAP. A significant increase in the strength of the Ti–10Mo–8Nb–6Zr alloy after ECAP makes it more promising for use in medicine.