高熵合金应用于异种金属焊接的研究现状及发展趋势

Research Status on the Application of High-entropy Alloys in Dissimilar Metal Welding

近年来,基于国内外对降低能耗的需求,“轻量化”在制造工业中受到广泛的重视。异种金属焊接可以综合发挥不同材料的性能优势,成为实现“轻量化”的有效途径。然而,在多数异种金属连接接头处会形成硬而脆的金属间化合物(IMC),严重降低焊接接头的强度和韧性。高熵合金兼具高熵效应与迟滞扩散效应,使其具有作为中间层材料或者钎料应用于异种金属连接以改善IMC带来的问题的巨大潜力。本文综述了近年来将高熵合金作为异种金属焊接中间层材料/钎料的相关探索性研究,重点关注高熵合金对焊接界面IMC的产生、微观组织和焊接接头力学性能的影响。综合分析相关研究,结合分析作为金属基复合材料增强体以及与铝合金、钢和钛合金等传统材料的异种金属焊接时所产生的高熵合金/传统金属界面组织特征,指出高熵合金确有作为中间层材料/钎料应用于不同类型异种金属焊接的潜力。为了推进高熵合金在这一方向上的应用,需要开展更加系统和深入的机理性研究以揭示高熵合金改善界面组织的机理,并针对不同异种金属体系优化出高熵合金中间层材料/钎料成分;此外,有必要开展“放大”研究以模拟实际工况下的作用效果。

Manufacturing industry has been pursuing“light-weighting”to reduce energy consumption.Property advantages of different materials can be well merged in a dissimilar metal welds/joints;thus dissimilar metal welding is one of the most effective approaches to achieving“light-weighting”.However,hard and brittle intermetallic compounds(IMCs)tend to form at the welding interfaces and to significantly reduce the strength and toughness of the welds.The formation of interface IMC would be prohibited or even avoided by using high entropy alloys(HEAs)as“interlayer”materials during dissimilar metal welding/joining.This possibility is a result of the synergistic cooperation of HEAs’high entropy effect and sluggish diffusion effect.Current explorations on the application of HEAs in this area are reviewed in the present paper,focusing on the effects of HEAs on the IMC formation,microstructure and mechanical properties of the joints.Despite the great potential,more fundamental stu-dies are needed to mechanistically understand the effects of HEAs on the microstructure and mechanical properties of different weld interfaces.In addition,studies should be gradually switched from laboratory-scale materials to industry-scale materials to further promote the application.