La2O3对激光熔覆Inconel718合金熔覆层的影响

Effect of La2O3 on Cladding Layer on Inconel718 Alloy by Laser Cladding

采用激光熔覆工艺在45钢表面制备了不同La2O3含量的Inconel718激光熔覆层。利用扫描电镜、X射线衍射仪、能谱仪和金相显微镜对该熔覆层的显微组织、物相组成、元素偏析和Laves相分布进行分析。结果表明:加入La2O3细化了熔覆层的晶粒,熔覆层与基体结合更加紧密,表面无明显裂纹和毛刺;加入La2O3抑制了Nb的偏析,减少了Laves相的形成,当La2O3含量为0.6%时Laves相的体积分数最少,同时不同含量La2O3的熔覆层析出了不同类型的La化合物;加入La2O3后熔覆层的硬度升高,当La2O3含量为0.7%时,熔覆层的显微硬度最高。

Inconel718 laser cladding layer with different La2O3cont e nt was prepared on 45 steel by laser cladding technology.The microstructure,phase composition,elemental segregation and Laves phase distribution of the cladding layer were investigated by SEM,XRD,EDS and metalloscope.The results show that the grain of the cladding layer is fined by the addition of La2O3,and the bonding between the cladding layer and the substrate is closer.No obvious cracks and glitches appear on the surface.The addition of La2O3inhibits the segregation of Nb and decrease the formation of Laves phase,and when the content of La2O3is 0.6%,the volume fraction of Laves phase is least,and then the cladding layer with different La2O3content precipitates different types of La compound.The hardness of the cladding layer increases with the addition of La2O3.When La2O3content is 0.7%,the microhardness of the cladding layer is highest.