电磁辅助激光成形修复GH4169合金Laves相分析

GH4169 alloy samples with V-grooves were experimentally repaired by electromagnetic stirring assisted laser repairing under different magnetic field currents. The morphologies and volume fraction of Laves in the repaired zone were compared, and the contents of Nb element in the matrix γ and the hardness of the repaired sample were measured by changing the magnetic field currents to explain the relationship between the magnetic field currents and the element segregation as well as mechanical properties. The results show that with the assistance of electromagnetic field, the morphology of Laves is obviously changed from reticulate to rod-like and granular shape and its volume fraction is decreased. The content of Nb element in the matrix γ is increased with the increase of the magnetic field current. When the magnetic stirring current is 60 A, the content of Nb element is 3.72 wt%, and it is increased by 0.33% compared to that without electromagnetic stirring. The hardness test shows that the electromagnetic stirring greatly increases the hardness of the repaired sample, which is related to the increase in the solid solubility of alloy elements such as Nb in the γ phase of dendrite core. The electromagnetic stirring improves both the flow of liquid metal in the melting pool vertical to the dendrite growth direction and the homogeneous distribution of solute element; as a result, the dendrite arm is more developed and the eutectic structure is more homogeneous.