A novel approach to control the thermal/stress-induced products of body-centered cubic titanium alloys in terms of specific orientation moduli

Abstract

β-type (body-centered cubic) titanium alloys have attracted significant attention owing to their variety of thermal-induced metastable phases and stress-induced deformation modes. However, the correlation between alloying elements and displacive mechanisms, including shear, shuffle, and collapse, in alloy design remains inadequately understood. This study demonstrated that common alloying elements in Ti-M binary alloys (M = Fe, Mo, Nb, V, Zr, and Al) formed stable cluster structures such as “M-Ti-M” or “M-M” along the <111>_β, <110>_β, and <100>_β directions, leading to the discrepancies among specific orientation moduli. The Young's modulus ($E_{100}$), tetragonal shear elastic constant (C′), and shear modulus ($G_{111}$) were positive when the contents of Fe, Mo, V, and Nb were higher than 3.5, 9, 12.5, and 21 wt.%, respectively, but negative for the Zr and Al elements. By controlling the thermal/stress-induced products in Ti-Mo-Nb-Zr-Al alloys through specific orientation moduli, experimental verification was feasible. A Ti-13.7Mo-3.4Nb-2.6Zr-0.9Al quinary alloy with significant {332}<113>_β twinning-induced plasticity effect was successfully designed, with $E_{100}$ (22.9 GPa), C′ (7.8 GPa), and $G_{111}$ (10.7 GPa). This study proposed a novel insight into the design of multi-component β-type titanium alloys with advanced performance based on specific orientation moduli.