GH4169合金作为航空航天发动机重要的热端部件材料，在高温富氧环境下服役时易发生金属燃烧，导致 灾难性事故。 基于自主研制的金属材料富氧燃烧实验设备，研究了激光选区熔化制备GH4169合金的阻燃性能和燃烧 行为，对其在高温下的使用具有重要意义。激光选区熔化成型GH4169合金沉积态显微组织呈现典型的鱼鳞状形貌，晶 粒取向以<001>方向为主并生成跨越多个熔池生长的柱状晶，在晶界和枝晶间析出了大量岛链状Laves相。 燃烧结果 表明，激光选区熔化成型制备的GH4169合金在99.5%纯O2室温点燃条件下，燃烧阈值约为3.7MPa，与锻造GH4169 合金的阻燃性能相当。燃烧区形貌分析表明，Al、Ti、Nb等元素是易燃烧元素，大量参与燃烧形成氧化物。Ni、Fe是不易 燃烧元素，其中Ni富集在熔化区。 热影响区存在大量的Laves熔化孔洞。 由于Laves相富含Nb、Ti等高燃烧热值元素 且熔点较低，在燃烧时会优先基体熔化参与燃烧，对合金的阻燃性能十分不利。因此，为了改善合金阻燃性能，需改善激 光选区熔化成型工艺和制定合理的热处理制度消除Laves相。

GH4169 alloys are important end component materials for aerospace engines. When serving in a high-temperature and oxygen-rich environment, metal combustion is prone to occur, resulting in catastrophic accidents. On the basis of the self-developed experimental equipment for the oxygen-enriched combustion of metal materials, the flame retardancy and combustion behavior of the GH4169 alloy prepared by selective laser melting were studied, which is highly important for its use at high temperatures. The microstructure of the as-built GH4169 alloy shows a typical fish-scale morphology. The grain texture is oriented mainly in the <001> direction and generates columnar crystals that grow across multiple molten pools. The precipitated phase is mainly the island-chain Laves phase, which precipitates at the grain boundaries and interdendrites. The combustion results show that the burning pressure threshold of SLM-GH4169 is approximately 3.7 MPa under 99.5% pure O2 ignition at room temperature, which is equivalent to the flame retardancy of the forged GH4169 alloy. The analysis of the morphology of the combustion zone revealed that Al, Ti, Nb and other elements are flammable, and many of these elements participate in combustion to form oxides. Ni does not burn easily and is enriched in the melting zone. Many holes are observed in the heat-affected zone, which are caused by the melting of the Laves phase. Because the Laves phase is rich in high-combustion calorific value elements such as Nb and Ti and has a low melting point, it will preferentially melt compared with the matrix and participate in burning during combustion, which is very  unfavourable to the flame retardancy of the alloy. Therefore, to improve the flame retardant properties of the alloy, it is necessary to improve the laser selective melting process and formulate a reasonable heat treatment system to eliminate the Laves phase.