Research on gamma TiAl-based alloy sheet fabricated by EB-PVD

Gamma TiAl-based alloy sheet with 150 mm × 100 mm × 0.4 mm was fabricated successfully by EB-PVD process, a new technique for producing sheet. The phase composition and micrographs of fractures of the deposited and annealed samples were analyzed by scanning electron microscopy (SEM) and X ray photoelectron spectra (XRD). The results indicated that the deposited γ-TiAl based alloy sheet was composed of gamma;, α₂ and τ phase, and the quality of the surface was well. There was spontaneous lamination inside the sheet and the microstructure was columnar crystal, which transformed into equiaxed crystal with T phase disappeared, α₂ phase decreased obviously, and the lamination trended to eliminate after vacuum heat treatment at 1000°C/16 h. The fracture of the material was diverted from the manner of intergranular brittle fracture to the manner of intergranular brittle fracture with dimple gliding fracture.