采用Ni基钎料和Cu中间层真空钎焊W/CuCrZr的接头组织和性能研究

Microstructure and Properties of W/CuCrZr Joint Vacuum Brazed with Ni Based Solder and Cu Interlayer

以20μm厚的纯Cu片作为中间层,采用20μm厚的非晶态Ni基钎料箔在在900、930、950℃下保温10min真空钎焊W和CuCrZr合金。采用SEM和EDS分析了钎焊接头的界面形貌,检测钎焊接头的剪切强度及显微硬度。结果表明,中间层Cu与母材CuCrZr合金一侧界面结合良好,在CuCrZr合金一侧形成了钎焊热影响区;钎料与W母材界面处形成了反应层,在W母材侧有微裂纹。随着钎焊温度的升高,W侧裂纹增多,造成接头性能的迅速恶化。W和CuCrZr的钎焊温度最好控制在930℃以下。以纯Cu片为中间层,采用Ni基钎料钎焊W和CuCrZr的过程,实质上是Ni与Cu、W互相扩散并反应生成化合物层和固溶体的过程。钎焊接头的最佳剪切强度为144MPa,断裂主要发生在W母材及W与反应层之间的界面。钎缝区域的显微硬度随钎焊温度的升高而降低,CuCrZr合金焊接热影响区的硬度高于其母材。

The vacuum brazing of W and CuCrZr alloy was carried out by using 20 μm thick amorphous Ni based solder foil and the interlayer of 20 μm thick pure Cu foil under the temperature of 900, 930 and 950℃ for 10 min. The interfacial morphologies of the brazed joints were analyzed by SEM and EDS, and the shear strength and micro hardness of the brazed joints were tested. The results show that the bonding between the Cu interlayer and the base metal CuCrZr alloy is good, and the brazing heat affected zone is formed at the side of CuCrZr alloy. The reaction layer is formed between the interface of the solder and W base metal, and there is microcrack at the side of W base metal. With the increase of brazing temperature, the cracks at the W side increase, which results in rapid deterioration of the joint properties. The brazing temperature of W and CuCrZr should be controlled below 930 ℃. The brazing process of W and CuCrZr with Ni based solder and pure Cu foil interlayer is essentially the process of diffusion and reaction between Ni and Cu, W to form compound layer and solid solution. The optimum shear strength of the brazed joint is 144 MPa, and the fracture mainly occurs at W base metal and the interface between W and reaction layer. The microhardness of the brazing zone decreases with the increase of brazing temperature. The hardness of the heat affected zone of CuCrZr alloy is higher than that of the base metal.