铝合金/钢异种金属激光熔钎焊技术研究进展

Research Progress of Laser Brazing Technology for Dissimilar Metals of Aluminum Alloy and Steel

铝合金/钢异种金属激光熔钎焊技术具有能量密度高、升温和冷却速度快、熔化位置控制精确、焊后变形小、自动化程度高等优势,特别适用于汽车制造行业。从铝合金与钢界面润湿铺展、界面微观调控、熔钎焊接头性能评价三个方面对国内外铝合金/钢异种金属激光熔钎焊技术的研究成果进行了综述,重点介绍了金属镀层、钎剂、母材热场对铝合金与钢激光熔钎焊过程中的界面润湿铺展的影响,归纳了界面热场、辅助能场、坡口面角度、合金元素对铝合金与钢激光熔钎焊过程中的界面微观调控作用,总结了铝合金与钢激光熔钎焊接头性能的评价方法。并指出优质、高效、高可靠的铝合金/钢异种金属激光熔钎焊技术仍需要解决以下四方面的问题:钢母材表面钎料润湿铺展的精准可控;铝合金/钢激光熔钎焊界面反应的精确可调;铝合金/钢激光熔钎焊接头的高强韧设计;铝合金/钢熔钎焊接头性能的可靠性评价。

Laser brazing technology for dissimilar metals of aluminum alloy and steel is a technology that uses laser as welding heat source,under the premise of ensuring that the high melting point steel matrix does not melt,the low melting point aluminum alloy matrix is melted and a fusion welding joint is formed with the melted filler metal,and the liquid aluminum alloy matrix and the filler metal are spread on the steel surface that is not melted and form a brazing joint to realize the highquality and high-strength metallurgical connection between aluminum alloy and steel.This paper reviewed the research results of aluminum alloy/steel dissimilar metal laser brazing technology at home and abroad from three aspects:interface wetting spreading of aluminum alloy and steel interface,micro-control of interface,and performance evaluation of brazing joint.It focuses on introducing the influence of metal coating,brazing agent and parent material thermal field on the interface wetting spreading of aluminum alloy and steel laser brazing process,summarizing the role of interface thermal field,auxiliary energy field,groove surface angle and alloy elements in the micro-control of aluminum alloy and steel laser brazing process,and summarizing the evaluation methods of aluminum alloy and steel laser brazing joint performance.At present,domestic and foreign scholars had done a lot of research work on aluminum alloy/steel laser brazing,and had achieved many creative technical achievements,but high-quality,efficient and reliable aluminum alloy steel dissimilar metal laser brazing technology still needs to solve the following four problems:precise and controllable wetting spreading of steel parent material surface brazing agent;precise and adjustable reaction of aluminum alloy/steel laser brazing interface;high strength and toughness design of aluminum alloy/steel laser brazing joint;and reliability evaluation of aluminum alloy/steel brazing joint performance.