采用选区激光熔化(SLM)成形方法,对SRR99镍基高温合金进行了定向凝固实验,测试了试样的显微组织、相组成及元素偏析情况。结果表明,沉积层与铸态基板间能形成良好的冶金结合,沉积试样组织由γ相和γ′相组成,沉积层与铸态基板组织在衍射角为50.78°时均有一个最强衍射峰,基板的生长取向在SLM沉积组织中得到了很好的延续,且试样的一次枝晶间距仅为1~2μm,二次臂退化甚至消失。各合金元素的偏析比均接近1,元素在枝晶间和枝晶干的分布较均匀。 Directional solidification experiment of SRR99 nickel base superalloy was carried out by selective laser melting (SLM) forming method. The microstructure, phase composition and element segregation of the sample were tested. The results show that a good metallurgical bond between the deposited layer and the as-cast substrate can be obtained. The microstructure of the deposited sample is composed of γ phase and γ ’phase. When the diffraction angle is 50.78 °, the deposited layer and as-cast substrate have a strongest diffraction The growth orientation of the substrate and the substrate was well extended in the deposited SLM. The primary dendrite spacing of the samples was only 1 ~ 2μm, and the secondary arms degenerated or disappeared. The segregation ratios of all the alloying elements are close to 1, and the distribution of elements in dendrites and dendrites is even.