Microstructure Evolution of Ti2AlNb-based Alloy by Laser Solid Forming

Abstract:

Microstructure evolution and hardness distribution of as-deposited Ti2A1Nb-based alloy by laser solid forming (LSF) was investigated through SEM, XRD and TEM. The results indicate that the LSFed Ti2A1Nb-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 Ti2A1Nb-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.