Fusion zone microstructure of laser beam welded directionally solidified Ni3Al-base alloy IC6

The fusion zone microstructure of laser welded alloy IC6 was examined. Extensive weld-metal cracking was observed to be closely associated with non-equilibrium eutectic-type microconstituents identified as consisting of γ, γ′ and NiMo (Y) phases. Their formation has been related to modification of primary solidification path due to reduced solutal microsegregation.