表面冲击改善铝合金搅拌摩擦焊接头应力腐蚀抗力的研究进展

铝合金广泛应用于航空航天、高速列车等新型装备,搅拌摩擦焊是这些装备的重要制造方法之一。然而,这些焊接结构在建造、服役过程中往往受到腐蚀环境的影响,在外力或残余应力耦合作用下极易发生应力腐蚀。诸多研究证实表面冲击技术可以提高铝合金的抗应力腐蚀性能,然而关于其防护机理尚处于推测阶段,至今没有统一定论。从应力腐蚀的力学因素和腐蚀因素两方面出发,剖析表面冲击对材料力学性能和耐腐蚀性能的影响,在此基础上,提出了表面冲击抑制铝合金应力腐蚀作用机制的研究方向,即通过构建关系模型定量表征改性层力学因素和腐蚀因素对接头应力腐蚀抗力的贡献率,可为阐明表面冲击抑制铝合金FSW接头应力腐蚀的关键因素及作用机理奠定基础,并为冲击工艺的优化提供理论支持。

Research Progress of Surface Impact Treatment Improved Stress Corrosion Cracking Resistance of Friction Stir Welded Aluminium Alloys

Aluminium alloy is widely used in aerospace, high-speed trains and other new equipment. Friction stir welding is an important manufacturing method for these equipments. However, these welded structures are often affected by the corrosive environment during construction and service, and stress corrosion cracking (SCC) is highly likely to occur under the coupling of external force or residual stress. Many studies have confirmed that surface impact can improve the SCC resistance of aluminum alloy. However, the protection mechanism is still in the speculative stage, and no consensus has been reached yet. Based on the mechanical and corrosion factors of SCC, the effects of surface impact on the mechanical properties and corrosion resistance of materials were discussed. And, on this basis, the research direction of improving the SCC resistance of friction stir welded joints of aluminum alloy by surface impact treatment was put forward. That is, to quantitatively reveal the contribution of mechanical factor and corrosion factor in the modified layer to stress corrosion resistance. It can lay a foundation for clarifying the key factors and mechanism of surface impact to inhibit stress corrosion of aluminum alloy FSW joints, and provide theoretical support for optimization of impact process.