Abstract:
The low-temperature deformation behavior of VNbTa entropy alloys with equiatomic ratio and body centered cubic structure was systematically investigated through low-temperature tensile testing. The results indicate that the alloy has excellent low-temperature strain hardening ability, which results in a fracture elongation of 27% and a tensile strength of up to 1930 MPa. Microstructural evolution analysis reveals that the twisted bands and 112< 111> deformation twins formed during the deformation process effectively regulate shear strain and promote the improvement of alloy plasticity and strength.In addition, screw dislocation entanglement, dislocation bands, and their interaction also contribute significantly to the strength and work hardening ability of the alloy. Therefore, the excellent low-temperature mechanical properties of VNbTa medium entropy alloy are attributed to the synergistic effect of 112< 111> deformation twins, twisted bands, screw dislocation slip and interaction.