K418合金和42CrMo钢激光焊焊缝的微观组织

Microstructure of laser welded seam of cast Ni-base superalloy K418 and 42CrMo steel

采用透射电镜及附带能谱(TEM-EDS)对K418高温合金涡轮盘和42CrMo合金钢转轴激光焊焊缝的微观组织进行了分析。结果表明:焊缝主要由树枝状非平衡凝固的FeCrNiC(γ)固溶体组成,此外,还有少量细小、弥散的Ni3Alγ′相、Laves颗粒和少量MC碳化物分布在树枝晶之间区域;根据热动力学原理对形成这一组织特征的原因进行了简要讨论。

Microstructure of laser welded seam of K418 superalloy turbo disk and alloy steel 42CrMo shaft was characterized by transmission electron microscopy（TEM） and energy dispersive spectrometer（EDS）.Results show that the laser welded seam has non-equilibrium solidified microstructure consisting of FeCrNiC（γ） austenite solid solution dendrites as the dominant and some fine and dispersed Ni3Alγ′ phase and Laves particles as well as little amount of MC carbides distributed in the interdendritic regions.Mechanism of the formation of the microstructure is briefly discussed based on thermal-dynamics principles.