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

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.