Fracture Morphology and Residual Stresses of TiAl-Based Alloys Sheet Fabricated by EB-PVD
The TiAl-based alloys sheet with 150 mm × 100 mm × 0.4 mm was fabricated successfully by using EB-PVD method. The fracture morphology and residual stresses of the sheet were analyzed by SEM, numerical calculation and X-ray stress analyzer. The results indicate that before stripping, the depositional layers have a higher compressive stress, and the substrate has a very lower tensile stress. For the isolated TiAl-based alloys sheet, the microstructure of as-deposited sheet is columnar crystal, and the residual stresses distribution on the free surface has a trend that its magnitude decreased gradually from center to edges. After vacuum annealing at 1273 K for 16 h, the columnar crystal transforms into the equiaxed, the residual stresses on the free surface are eliminated ultimately, and the fracture of the material is diverted from the manner of intergranular fracture to the mixed manner of intergranular fracture with cleavage fracture.
M.H. Aliabadi, Qingfen Li, Li Li and F.-G. Buchholz
D. M. Zhang et al., "Fracture Morphology and Residual Stresses of TiAl-Based Alloys Sheet Fabricated by EB-PVD ", Key Engineering Materials, Vols. 324-325, pp. 307-310, 2006