纳米陶瓷颗粒对铝合金焊缝强度和微观组织影响的研究进展

Research Progress on the Influence of Nanoparticles on Weld Strength and Microstructure of Aluminum Alloy

铝合金材料具有密度小、比强度高、耐腐蚀性好等特点,是现代社会应用最为广泛的材料之一。纳米陶瓷颗粒具有高强度、高模量、热稳定性好等优点,随着纳米材料技术的不断发展,纳米陶瓷颗粒作为强化材料在铝合金焊接中的应用越来越得到重视。铝合金焊接过程中存在焊缝组织粗化、接头软化和热裂纹等问题,导致铝合金接头在服役过程中失效。纳米颗粒添加入焊缝,具有细化焊缝晶粒、修饰二次相形貌、降低焊接热裂纹、强化焊缝性能的作用,已被用于航空、航天、汽车、高速动车等高强度铝合金的焊接领域。近些年的研究表明,纳米颗粒的含量和成分等物理性质、焊接工艺以及纳米颗粒-基体的界面显著影响焊缝的组织和力学性能。随着纳米颗粒含量增加,焊缝强度显著提高,但是高含量的纳米颗粒容易诱发团聚。不同种类的纳米颗粒能够起到协同强化作用,此外焊接过程中焊接电流、搅拌摩擦参数以及超声和振动等工艺方法可以促使熔池流动提高纳米颗粒在焊缝中的分散程度,从而增强纳米颗粒的强化效果。本文综述了近年来国内外关于纳米陶瓷颗粒在铝合金焊接中的最新研究现状,归纳总结了纳米陶瓷颗粒的物理性质和焊接工艺对复合焊缝强度的影响,重点分析了纳米陶瓷颗粒对焊缝微观组织和热裂纹的影响,介绍了纳米颗粒与基体的界面结合问题,并展望了其未来的研究方向。

Aluminum alloy is one of the most widely used materials in modern society because of its characteristics such as low density,high specific strength and good corrosion resistance.Nano-ceramic particles have the advantages of high strength,high modulus,good thermal stability,etc.With the continuous development of nano-material technology,the application of nano-ceramic particles as strengthening materials in aluminum alloy welding has been paid more and more attention.In the process of aluminum alloy welding,the problems such as weld microstructure roughening,joint softening and thermal crack are easy to lead to the failure of aluminum alloy joint in service.The addition of nanoparticles into welding seams has the functions of refining weld grain,modifying secondary phase morphology,reducing welding heat crack,and strengthening weld performance.It has been used in the welding field of high strength aluminum alloy such as aviation,aerospace,automobile and high-speed bullet vehicle.Recent studies have shown that the content,composition and other physical properties of nanoparticles,welding technology and nanoparticle-matrix interface have significant effects on the microstructure and mechanical properties of welding seams.With the increase of the content of nanoparticles,the weld strength was significantly increased,but the high content of nanoparticles was easy to induce agglomeration.Different kinds of nanoparticles can play a synergistic strengthening role.In addition,welding current,friction stir parameters,ultrasonic,vibration and other technological methods in the welding process can promote the flow of molten pool to improve the dispersion degree of nanoparticles in the welding seam and enhance the strengthening effect of nanoparticles.In this paper,the latest research status of nano-ceramic particles in aluminum alloy welding in recent years was reviewed,and the influence of the physical properties and welding technology of nano-ceramic particles on the strength of composite weld was summarized.The influence of nano-ceramic particles on the microstructure and thermal crack of welding seam was analyzed,the interface bonding between nano-particles and matrix was discussed,and the future research direction was prospected.