面向航空航天的金属多孔夹层结构钎焊研究现状及发展趋势

Research Status and Development Trend of Brazing Metal Porous Sandwich Structure Toward Aerospace

金属多孔夹层结构具有质轻,比强度、比刚度高,耐高温、耐腐蚀,消音、隔热等优异性能,在航空航天领域高端装备的应用受到越来越多的关注。钎焊法是实现金属多孔夹层结构芯体与面板连接的首选方法。然而夹芯与面板大面积钎焊过程中易产生钎料对薄壁母材溶蚀、焊合率低、焊接变形大、界面易形成连续脆性反应产物等缺陷,因此金属多孔夹层大面积钎焊仍有较大难度,迫切需要开展金属多孔夹层钎焊基础研究。国内外学者针对连接界面微区反应产物的种类和分布调控、薄壁母材的溶解预测、薄壁夹芯的焊接热变形控制等难题,研究了钎焊界面组织调控新方法、钎焊工艺–钎角形态–接头组织–接头力学性能的整体对应关系,阐明接头的组织演化规律,优化接头的力学性能,具有重要的科学意义及工程应用价值。本文从金属多孔夹层结构钎焊接头界面微区调控、基于力学性能优化的钎焊接头微观形态设计、钎焊过程对结构力学性能的影响及焊后强化方法和液态钎料对母材的溶解预测模型等国内外研究进展进行综述。

Porous metal sandwich structure has light weight,high specific strength and stiffness,high temperature and corrosion resistance,sound dissipation,heat insulation and other excellent properties.The application of high-end equipment in the aerospace field is receiving more and more attention.Brazing is the preferred method to realize the joining between core and face sheets of porous metal sandwich structure.However,the process of large area brazing of core and face sheets is prone to defects such as melting of brazing filler to thin-walled base metals,low brazing rate,large brazing deformation and formation of continuous brittle reaction products at the interface,so large area brazing of porous metal sandwich structure is still difficult,and basic research on brazing of porous metal sandwich structure is urgently needed.Scholars at home and abroad pay attention to the adjusting of joining interface micro-reaction products for the type and distribution,dissolution prediction of thin-walled base metals,welding heat deformation control of thin-walled core and other challenges.The study about new methods of brazing interface microstructure control,brazing process–morphology of brazing fillet–microstructure of brazed joint–the mechanical properties of the joint was conducted to clarify the microstructure evolution of the brazed joint and optimize the mechanical properties of the joint.It has important scientific significance and the value of application.The progress of domestic and international research is reviewed in terms of the interface micro-zone control of the brazed joint of the metal porous sandwich structure,the micro-morphological design of the brazed joint based on the optimization of mechanical properties,the effect of the brazing process on the mechanical properties of the structure,and the predictive model for dissolution of base metals in molten brazing filler metal,respectively.