Titanium alloy is a kind of difficult-to-machine material, which needs to seek an efficient processing method. In this paper, the deposition samples of TB6 titanium alloy were prepared by laser deposition manufacturing. The internal microstructure of the as-deposited was analyzed by Optical Microscope(OM) and Scanning Electron Microscope(SEM). The formation mechanism of interlaminar bands and the variation law of microhardness were studied. The microstructure of TB6 titanium alloy prepared by laser deposition is composed of most equiaxed and a small part of original β grains elongated along the deposition direction and approximately ellipsoidal. The original β grains are mainly composed of primary α phase(αp), grain boundary α phase(αGB) and matrix β phase. The temperature fluctuation between the deposition layers in the laser deposition process leads to the change of αp phase size, which forms the layer band distribution with different contrasts.

The TB6 titanium alloy prepared by laser deposition is prone to uneven microstructure. In this paper, heat treatment was used to regulate the microstructure. Through the observation and analysis of microstructure and microhardness under different heat treatment states, the variation law of microhardness with the change of heat treatment process was explored. The results show that due to the distribution of layer bands in the as-depositeds of TB6 titanium alloy fabricated by laser deposition manufacturing. The microhardness decreases gradually with the increase of deposition height in a single deposited layer. The average microhardness at the dark band position is 377.4 HV0.2, while the microhardness at the top bright band position decreases by 7.3 %. Low temperature annealing treatment has little effect on the microhardness. After high temperature annealing treatment, the microhardness decreases by about 4.6 % compared with the deposition state. The secondary α phase (αs) precipitated after solution and aging treatment has obvious strengthening effect on the β matrix. The microhardness is greatly improved, and increases with the increase of solution temperature. The microhardness after solution and aging treatment at low and high temperatures is 10.0 % and 19.2 % higher than that of the deposited state, respectively.