Microstructure and Element Diffusion of Welded Seam Interface during Laser-Arc Hybrid Welding of Cemented Carbide and Invar Alloy

The joining of cemented carbide and invar alloy was obtained by laser-arc hybrid welding scanning electron microscopy, energy-dispersive spectrometers, electron probe micro analyzer were used to investigate the microstructure, chemical composition and element diffusion near interface. The results show that the combination of laser and arc eliminated η phases which were in the side of cemented carbide of welded seam interface. Fe4WC2 dendrite crystals were formed in the side of invar alloy. The element diffusion coefficient in the side of cemented carbide was higher than that under the condition of single arc welding. The diffusion coefficient of nickel and iron was up to 22.7 cm2·s-1, maximum arc welding diffusion distance was up to 200 μm.