Fine duplex Ti-48Al alloy with high strength produced by forging based on near-? microstructure

TiAl-based alloy is an excellent high-temperature structural material, but poor hot workability has been the bottleneck hindering its development. In this study, we take into account the hot workability and mechanical properties of Ti-48Al alloy through microstructure adjustment. Powder metallurgy Ti-48Al alloy prepared by vacuum sintering is used as the raw material, which has a near-gamma microstructure composed of equiaxed grains. Although the composition is simple, the alloy achieves high mechanical properties after forging with 75 % deformation. Controlling the forging temperature to 1300 degrees C can make the microstructure transform into a duplex structure composed of gamma/alpha 2 lamellar colonies and gamma equiaxed grains. As-forged alloy has an ultimate tensile strength of 650 +/- 17 MPa and a yield strength of 644 +/- 16 MPa at room temperature. It still maintains high strength at high temperature, with ultimate tensile strength of 684 +/- 19 MPa at 500 degrees C, 700 +/- 19 MPa at 700 degrees C, and 320 +/- 10 MPa at 900 degrees C. In addition, the alloy has good ductility with elongation of 58.2% due to dynamic recrystallization at 900 degrees C. (c) 2023 Elsevier B.V. All rights reserved.