脉冲等离子增材再制造Inconel 718合金的组织演变  

Microstructural evolution of Inconel 718 Ni-based superalloy remanufactured by pulsed plasma arc

作　　者：王凯博[1] 吕耀辉[1] 刘玉欣[1] 徐滨士[1] 

机构地区：[1]装甲兵工程学院装备再制造技术国防科技重点实验室,北京100072

出　　处：《金属热处理》2016年第9期1-5,共5页Heat Treatment of Metals

基　　金：国防973及军队科研项目

摘　　要：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-based superalloy was additive remanufactured by pulsed plasma arc welding, and the microstructure morphology and the precipitation principle of phases was investigated. Besides, the KGT model was used to calculate the spaces of primary dendrites. The results show that the microstructure of the as-deposited sample mainly consists of columnar dendrites which grow epitaxially along the deposition direction, and the obvious bounds exist between layers, and it changes as the trend of cellular dendrites→columnar dendrites→big columnar dendrites → equiaxed cellular structure from the bottom to the top section since the temperature gradient and cooling rate changed. The primary dendrites arm spaces are 19. 2, 29. 3 and 34. 1 μm respectively at the bottom, the middle and the top section of the as-deposited sample. A large number of irregular shapes Laves phases are precipitated in the interdendritic regions and the blocky MC carbides with diffuse distribution in grain boundary are closely related with Laves phases. The （γ＋Laves） eutectic phases are observed at the middle and the top sections of the as-deposited sample.

关 键 词：脉冲等离子 增材再制造 INCONEL 718合金 组织 KGT模型 

分 类 号：TG146[一般工业技术—材料科学与工程]