Effects of minor addition of Ni on hot-deformation behavior of gamma TiAl alloy

The hot deformation behavior of Ni-containing and Ni-free gamma TiAl alloys was examined, starting with the lamellar microstructure and the equiaxed near-gamma microstructure, to reveal the effects of minor Ni addition. It is found that the Ni addition is beneficial to the steady-state flow behavior, strain rate sensitivity and improves the hot deformability of the lamellar TiAl substantially. These effects are not be affected significantly by the microstructure transformation prior to the hot deformation.