Characterization of Ni-Cr-Mo alloy phase structures under DLD process

Direct laser deposition of Ni-Cr-Mo alloy has been carried out to study the phase structure transformation under various operating parameters. To assess the phase composition SEM, TEM and XRD analysis were performed. It clearly seen that the precipitation of straightening phases (γ' and γ") depends on the temperature gradients caused by different laser power. The nucleation of γ' phase starts at 750 W while γ" phase at 1000 W. The changes in temperature gradients lead to different diffusion condition across all the stage of laser power variation and formation of δ-phase, primary MC carbides and Laves phase. δ-phase of all samples did not change the shape and characterized only by plate-like shape.