Preparation of TiAl3-Al composite coating by cold spraying

TiAl3-Al coating was deposited on orthorhombic Ti2AlNb alloy substrate by cold spraying with the mixture of pure Al and Ti as the feedstock powder at a fixed molar ratio of 3:1 when the spraying distance, gas temperature and gas pressure for the process were 10 mm, 250 degrees C and 1.8 MPa, respectively. The as-sprayed coating was then subjected to heat treatment at 630 degrees C in argon atmosphere for 5 h at a heating rate of 3 degrees C/min and an argon gas flow rate of 40 mL/min. The obtained TiAl3-Al composite coating is about 212 mu m with a density of 3.16 g/cm(3) and a porosity of 14.69% in general. The microhardness and bonding strength for the composite coating are HV525 and 27.12 MPa.