采用脉冲等离子工艺增材再制造了Inconel 718镍基高温合金,并深入研究了再制造合金的组织形态及析出相分布规律,采用KGT模型对枝晶生长动力学进行定量计算。结果表明:沉积态合金组织以柱状枝晶为主,具有较强的外延生长特性,层与层之间有明显的界线。由于再制造过程中温度梯度和冷却速率的变化,自底部向顶部呈现胞状晶→柱状晶→粗大柱状枝晶→等轴晶的转变趋势,初生枝晶间距自底部向顶部分别为19.2、29.3和34.1μm。大量不规则的Laves相分布在枝晶间,MC碳化物弥散分布于晶界。在中部及顶部,有(γ+Laves)共晶相生成。 Inconel 718 Ni-base superalloy was fabricated by pulsed plasma process and the microstructure and morphology of the precipitated phase were further studied. The KGT model was used to quantitatively calculate the growth kinetics of dendrite. The results show that the as-deposited alloy is dominated by columnar dendrites and has strong epitaxial growth characteristics with distinct boundaries between layers. Due to the change of temperature gradient and cooling rate in remanufacturing process, the transition trend of cell crystal → columnar crystal → coarse columnar dendrite → equiaxed crystal from bottom to top was observed. The spacing of primary dendrites was 19.2,29.3 from the bottom to the top 34.1 μm. A large number of irregular Laves phase distribution in the dendrite, MC carbide dispersed in the grain boundary. In the middle and top, there are (γ + Laves) eutectic phases.