采用Cu-Zr箔/Cu箔/Cu—Zr箔中间层对Ti(C,N)-Al2O3陶瓷基复合材料进行了液相扩散连接实验,研究了辅助脉冲电流对元素扩散、界面反应产物及接头强化机制的影响.结果表明,液相扩散连接过程中辅助脉冲电流条件下可以在较低的焊接温度和较短的焊接时间内实现更高的接头强度.辅助脉冲电流液相扩散连接工艺显著改变了Zr和Cu在Ti(C,N)-Al2O3,陶瓷基复合材料和钎缝中的扩散行为,减少Zr的活性,抑制其与-Al2O3陶瓷颗粒发生激烈的化学反应.辅助脉冲电流可以抑制陶瓷颗粒相溶解进入焊缝以及界面扩散过渡层和Zr-Cu反应层的厚度,确保焊缝强化以及界面强化,这是辅助脉冲电流液相扩散连接接头具有较高强度水平的关键所在.
Ceramic matrix composites (CMCs) is attracted in airspace and nuclear engineering due to their high temperature, corrosion and wearing resistance, but the usage is limited by the joining between CMC and other metals due to obvious incompatibility on physical and chemical aspects on them. The liquid phase-diffusion bonding (LPDB) on Ti(C, N)-Al2O3 CMC/Cu joint was studied using the Cu-Zr foil/Cu foil/Cu-Zr foil sanwich as an interlayer in this work. Auxiliary pulse current was also added to control the elemental diffusion and interfacial reaction during LPDB. The element diffusion and reacted products at the interface were analyzed with SEM, EPMA and EDS, and the joint strength was tested with four points bending method. The results show that with an auxiliary pulse current during LPDB, a higher joint strength is reached with a lower bonding temperature and a shorter holding time. The diffusion behavior of element Zr and Cu in CMC and the interfacial area is obviously changed, and the activity of Zr element and its chemical reaction with Al2O3 are depressed by the auxiliary pulse current during LPDB. The diffusion of ceramic partilces into the interface and the thickness of corresponding diffusion transition zone (DTZ) and Zr-Cu interfacial reaction zone (IRZ) at the interface are also depressed by the auxiliary pulse current, which strengthens the interface, and is always kept an higher joint strength.