Shear band formation and texture evolution in 2 vol. % TiC/near-β titanium matrix composites during cold rolling

Abstract

High strength β titanium matrix composites (TMCs) exhibit complex deformation mechanisms, with the shear band being particularly prevalent. However, the underlying mechanism of shear band formation remains unclear. In this article, we systematically investigated its mechanism and the evolution of texture during cold rolling in a TMC – 2 vol% TiC/Ti-4Al-1Sn-2Zr-5Mo-8 V-2.5Cr, which was cold-rolled after solution treatment in the two-phase and single-phase zones. The results reveal that a typical γ-texture configuration, characterized by specific compositions of (111) 〈1−10〉 and (111) 〈0−11〉, gradually develops within the TMC matrix with increasing rolling deformation, storing greater strain energy. Notably, fewer shear bands formed in the cold-rolled plate matrix after solution treatment in the two-phase zone, attributed to the presence of α_p phase. The diffusely distributed α_p, in conjunction with TiC particles, effectively hinders dislocation movement, thereby reducing dislocation entanglement density and subsequent lattice distortions. This reduction in lattice distortion minimizes shear band formation. Importantly, the presence of precipitated α_p and reduced shear band density result in superior mechanical properties in the cold-rolled plates solution treated in the two-phase zone.