Making titanium alloys ultrahigh strength and toughness synergy through deformation kinks-me diate d hierarchical α-precipitation

Titanium alloys engineered in structural applications achieve ultrahigh strength primarily through precipitation strengthening of secondary alpha-phase ( alpha(s )) during aging, while they often experience compromised ductility and toughness due to traditional strength-toughness tradeoff. In this study, we propose a novel strategy to address this conflict by introducing deformation kinks prior to conventional cold rolling (CR) and aging processes. These kinks are produced by cold forging (CF) to create macroscopic lamellar structures in beta-grains, which alter strain partitioning during subsequent CR and ultimately tailor alpha(s)- precipitation upon aging. As a result, an ultrafine duplex ( alpha(e) + beta )-structure is formed within kink interiors, while hierarchical alpha(s)-precipitates are generated in the external beta-matrix. This unique microstructure effectively enhances dislocation activity, promotes uniform plastic strain distribution and impedes crack propagation. Consequently, a simple Ti-V binary titanium alloy exhibits exceptional properties with ultrahigh strength-1636 MPa, decent ductility-5.4 % and appreciable fracture toughness- 36.1 MPa m(1/2). The synergetic properties surpass those obtained through traditional CR and aging processes for the alloy and even outperform numerous multielement engineering titanium alloys reported in literature. Our findings open up a new avenue for overcoming the strength-toughness tradeoff of ultrahigh-strength titanium alloys, and also offer a facile production route towards structural materials for advanced performance. (c) 2024 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.