钛合金与铝合金异种金属钎焊的研究进展

Research Progress on Dissimilar Metal Brazing of Titanium Alloy and Aluminum Alloy

钛合金在经济性和加工性方面不理想,导致其在实际工程应用中受限,而铝合金在某种程度上可以弥补这种缺陷,因此将钛合金和铝合金复合使用的构想应运而生。对钛合金和铝合金异种金属的可焊性进行了分析,以钛合金和铝合金钎焊为研究对象,重点论述了钛合金与铝合金钎焊连接所用的钎料及工艺等的国内外研究现状,并着重分析了Al基和Zn基钎料的润湿性、界面、钎缝组织及其优缺点。由相关文献分析可知,Al基钎料在真空、保护气氛或非真空外加辅助措施条件下对钛合金和铝合金都有良好的润湿性,但接头强度仍有待提高,金属间化合物较厚的问题需要通过优化钎料成分和焊接工艺进一步改善;Zn基钎料对钛合金的润湿性较差,但在适当的焊接工艺下可以获得力学性能较好的Ti/Al接头,剪切强度可达141MPa;使用Sn基和Cu基钎料获得的Ti/Al接头的力学性能低于Al基和Zn基钎料,且Sn基的钎料对两种母材的润湿性都较差,需要对母材表面进行预处理。

As titanium alloy has poor economy and process ability, its application in the practical engineering is limited. But the aluminum alloy can make up for these defects to a certain extent, so the application of dissimilar bonding of the titanium alloy with the aluminum alloy comes into being. In this paper, the weldability of titanium alloy and aluminum alloy was discussed. With the brazing of titanium alloy and aluminum alloy as the research object, the current research status on brazing filler and the brazing technique on their bonding at home and abroad were demonstrated emphatically. The wettability, interface, microstructure of the brazing joint and the advantages, disadvantages of using the Al-based and Zn-based filler metals were also discussed. According to the analysis of the relevant literatures, the Al-based filler metal had good wettability to the titanium alloy and aluminum alloy under different conditions, such as vacuum, protective atmosphere or non-vacuum plus auxiliary measures, but the joint strength still needed further improvement. The problem of the thicker intermetallic compounds layer also needed to be further improved by optimizing the solder composition and the brazing process. The wettability of the Zn-based solder to the titanium alloy was poor, but the Ti/Al joint with good mechanical properties could be obtained under an appropriate brazing process(shear strength could up to 141 MPa). Compared with the Ti/Al joints obtained using Sn-based and Cu-based filler metals, the mechanical properties of the joints are lower than those obtained using the Al-based and Zn-based filler metals. The Zn-based filler metal has poor wettability to the two types of base metals. Pretreatment is required for the base metal surface.