Simultaneously improved strength and elongation at cryogenic temperature in Ti–5Al–1V–1Sn–1Zr-0.8Mo alloy with a bimodal structure

Abstract The tensile properties and deformed microstructures of Ti–5Al–1V–1Sn–1Zr-0.8Mo (Ti5111) alloy with a bimodal structure under different deformation temperatures are investigated. As the deformation temperature decreases from 0 °C to −196 °C, the tensile strength, and elongation of Ti5111 increase simultaneously. The distinguishing characteristic of the deformed structure is the presence of { 10 1 ‾ 2 } 10 1 ‾ 1 deformation twins (DTs) at −196 °C. These DTs can improve the tensile elongation by twinning-induced plasticity (TWIP), and make additional grains amenable for dislocation slip by changing the local microstructure orientation, promoting homogeneous deformation and contribute toward a higher elongation at −196 °C than that at 0 °C. The enhanced tensile strength at −196 °C is attributed to the coupling influence of the higher stress of dislocation slip at cryogenic temperature and the deformation twins-induced grain refinement.