Balancing strength and ductility by controllable heat-treatment twinning in a near β-Ti alloy

A new thermomechanical process was applied to a near-beta Ti-5A1-5Mo-5V-1Cr-1Fe alloy to induce twinning. The resulting combination of ultrafine grains and heat-treatment twins endowed the alloy with excellent tensile strength (1544 MPa) and elongation (13%). beta-Field cross-rolling formed micro-sized beta grains, and ultrafine alpha particles precipitated from pre-existing dense dislocation structures and martensites. alpha-Twinning occurred during heat treatment and continuously evolved with the ongoing heat treatment time. A precisely controlled heat treatment time enabled the distribution of nanosized twins throughout the alpha laths, simultaneously improving strength and ductility. The results of this study pave the way for the development of customised titanium alloys with significantly improved mechanical properties. (C) 2020 The Author(s). Published by Elsevier B.V.