Microstructure evolution of Ti₂AlNb-based alloy by laser solid forming

Microstructure evolution and hardness distribution of as-deposited Ti₂AlNb-based alloy by laser solid forming (LSF) was investigated through SEM, XRD and TEM. The results indicate that the LSFed T₂AlNb-based alloy was constituted of B₂/β₀ phase (ordered-bbc) and O phase (orthorhombic). The as-deposited phase in the bottom and top area of the LSF Ti₂AlNb-based alloy sample is B₂ phase (Nb-based solid solution), while the phase in the middle area is O phase Widmanstǎttem. The phase evolution through bottom→middle→top is B₂/β₀ →B₂/β₀+ O→B₂/β₀. Therefore, the microhardness of the middle area for LSFed as-deposited Ti₂AlNb-based alloy is maximum, and that of the top and bottom is similar. The microhardness of the alloys increases with the laser power increasing.