BCC/B2 structure and dislocation strengthening behavior in high Ti content TiAlVCrNb high-entropy alloys

In this work, we designed and successfully prepared new lightweight refractory high entropy alloys (HEAs) Ti75Al10V5Cr5Nb5, Ti67Al12V7Cr7Nb7 and Ti55Al15V10Cr10Nb10 with BCC/B2 structure. It was found that TiAlVCrNb high-entropy alloy plasticity is mainly generated by dislocation aggregation at grain boundaries and intracrystalline, and strength is provided by solid solution strengthening and BCC/B2 structure. The results show that the Ti75Al10V5Cr5Nb5 high-entropy alloy have a great room temperature compressive plasticity of> 50% and a tensile elongation after break of 6% with the preferential orientation (200) and more dislocations, resulting in good plasticity. The Ti55Al15V10Cr10Nb10 high-entropy alloy has a room temperature compressive a yield strength of 1465 MPa and a compressive strength of 1835 MPa, as the Ti content decreases, the effect of solid solution strengthening will decrease, but the B2 structure content increases so that the mixed structure formed by BCC/B2 structure provides more strengthening. The light refractory high entropy alloy can control the Ti content to change the BCC/B2 structure content to obtain higher strength and plasticity.