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

Abstract

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 temperature-controlled cooling experiments can be obtained: B2+O two-phase and α2+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, α2 and O phases was identified as follows: {011}B2/β//{0001}α2, B2/β//α2, {110}B2/β//{001}O, B2/β//O, {0001}α2//{001}B2/β, α2// O. Last, the compression tests of these heat-treated samples were performed, and the microstructure-dependent mechanical properties were discussed.

Keywords

• Ti2AlNb alloy
• Vanadium alloying
• Microstructure evolution
• Mechanical properties