钨/钢异种金属电阻扩散焊接头组织与性能

The pure tungsten plate and the CLF-1 reduced activation ferritic/martensitic (RAFM) steel was welded successfully based on the Joule heat generated by the constant current output from the resistance seam welding, named resistance diffusion welding. Meanwhile, the graphite with high resistivity and the pure Fe foil were proposed as the thermal compensated auxiliary electrode and the interlayer in the welding process, respectively. The interfacial structure, joint strength, and fracture form of the obtained W/steel and W/Fe/steel welded joints were compared to reveal the role of the interlayer in the welding process. The results indicated that：due to the introduction of the interlayer between tungsten and RAFM steel, the interfacial structure of the obtained W/Fe/steel welded joint was changed significantly. The original W/Fe connection interface was replaced by two interfaces of W/Fe and Fe/steel. In addition, the addition of the interlayer led to an increase in the resistance of the entire welded joint, which improved the Joule heat generated in the welding process. Hence, the interdiffusion distance at the interface increased from 2 μm to 4 μm, and the obtained shear load of the W/Fe/steel welded joint reached 12 313.3 N, which was about 30.82% higher than the former. The real-time temperature field of the W/Fe/steel welded joint surface showed that the temperature of the auxiliary electrode graphite was the highest in the whole welding process. The highest temperature was 910 ℃ but was lower than the melting point of the base metal. This indicated that the mechanical properties of the welded joints were dominated by the interdiffusion of different elements, which was resistance diffusion welding. Moreover, the fracture morphology sketched that the addition of the interlayer resulted in the increase in the reaction area at the fracture surface, and the main fracture position was located at the W side, indicating that a good metallurgical bond was formed between tungsten and RAFM steel.