A novel insight of solid–liquid interaction effect during laser hybrid manufacturing Ti2AlNb alloy

Combining interlayer point-forging with laser-deposition (PF-LD) provides a new idea to in-situ modify coarse-grained structure and strong solidification texture during high-thermal additive manufacturing process. In this study, a well-designed step-experiment with one to three-pass PF-LD was conducted on columnar-grained Ti2AlNb substrate to elucidate a novel insight of solid–liquid interaction effect. The results revealed that the combination of localized micro-forging and laser re-heating was capable to produce randomly-distributed equiaxial structure via interlayer recrystallization behavior, at the same time it in turn had a positive effect on solidification grain refinement. The essential contribution of these fine-grained microstructures further created an acceleration effect to interlayer recrystallization behavior and promoted the full-equiaxial grain morphology of PF-LD Ti2AlNb part.