添加SiO_(2)纳米粉末AC辅助Al/Cu等离子弧熔钎焊接头组织及性能分析

Microstructure and Properties Analysis of AC Assisted Al/Cu Plasma ArcBrazing Joint by Adding SiO_(2)Nano-powder

从工艺方法改进和界面调控方面提出了添加SiO_(2)纳米粉末AC辅助Al/Cu等离子弧熔钎焊,实现了成形及力学性能良好的Al/Cu异种金属接头,并对界面处微观组织及接头力学性能进行了对应分析,对其界面形成的内在机理进行相应阐述。结果表明,AC辅助电弧的引入可显著改善Al在Cu母材表面的润湿铺展性能,接头有效连接长度由12.25 mm增加至15.2 mm;接头微观组织分析表明,纳米SiO_(2)吸附于Cu界面及IMC层,起到了扩散阻挡作用,阻碍了Al和Cu原子的反应和相互扩散,减小了焊接过程中界面IMC的厚度,减缓了等温时效过程中IMC的生长。同时,较大的有效连接长度和对IMC层的抑制作用使添加SiO_(2)纳米颗粒AC辅助电流值为45 A的接头断裂承受最大载荷为0.85 kN,断裂位置位于铝侧热影响区,接头力学性能较好。

The Al/Cu dissimilar metal joints with good forming and mechanical properties were achieved byAC assisted plasma arc brazing assisted with adding SiO_(2)nano-powder from the aspects of process improvement and interface control.The microstructure of the interface and the mechanical properties of the joint were analyzed,and the internal mechanism of the interface formation was described.The results show that the introduction of AC assisted arc can significantly improve the wetting and spreading properties of Al on Cu base metal surface,and the effective joint length increases from 12.25 mm to 15.2 mm.The microstructure analysis of the joint shows that nano-SiO_(2)adsorbs on Cu interface and IMC layer,which acts as diffusion barrier,impedes the reaction and mutual diffusion between Al and Cu atoms,reduces the thickness of IMC interface during welding,and slows down the growth of IMC during isothermal aging.At the same time,due to the larger effective connection length and the inhibition effect on the IMC layer,the joint with AC auxiliary current value of SiO_(2)nanoparticles added at 45 A bears the maximum fracture load of 0.85 kN,and the fracture is located in the heat-affected zone on the aluminum side,and the mechanical properties of the joint are good.