Microstructure evolution and mechanical properties of vanadium-bearing Ti-22Al-26Nb alloys obtained by controlled cooling from a single B2 region

To investigate the role of Vanadium element in Ti2AlNb-based alloy, Ti-22Al-26Nb-xV (x = 0, 2, 8) alloys were cooled from the B2 single-phase temperature (1300 C) at controlled process parameters. The isothermal preheating in the B2 single-phase zone contributes to the homogenization of microstructure and the elimination of micro-segregation in subsequent microstructure evolution. Two typical microstructures after temperaturecontrolled cooling experiments can be obtained: B2+O two-phase and alpha 2+B2+O three-phase microstructures. The effects of Vanadium content and cooling rate on phase transformation and microstructure evolution were analyzed. The crystallographic relationship between B2, alpha 2 and O phases was identified as follows: {011}B2/ beta//{0001}alpha 2, <111> B2/beta//<11 2 0>alpha 2, {110}B2/beta//{001}O, < 1 11> (B2/beta)//<1 1 0>(O), {0001}alpha 2//{001}(B2/beta), <11 2 0>alpha 2//<110>( O). Last, the compression tests of these heat-treated samples were performed, and the microstructure-dependent mechanical properties were discussed.