Effect of Annealing Treatment and Deposition Direction on Microstructures and Mechanical Properties of Laser Deposition Manufactured TA15 Titanium Alloy

TA15 titanium alloy bulk specimens were prepared by laser deposition. The effect of annealing treatment and deposition direction on the microstructure characteristics, the tensile properties and alpha phase deformation mechanism has been studied by OM, SEM and XRD. The results show that the aspect ratio of alpha phase rises with the increase of annealing temperature. The mechanical properties in the deposition direction are different from those in the vertical deposition direction. The tensile strength in the deposition direction is obviously lower than that in the vertical direction. Columnar grain boundary hinders alpha lamellar distortion. Alpha lamellar along the deposition direction deforms or fractures by extrusion and slippage. Different directions have their unique tensile fracture modes, which are ductile fracture along the deposition direction and semi-cleavage-ductile fracture along the vertical deposition direction.