Research progress of heat treatment technology and its application into remanufacturing cold sprayed coating

Cold spray technology is widely used in remanufacturing field such as repairing and strengthening high-value metal parts due to its low-temperature deposition characteristics. However, the remanufacturing coating prepared by cold spray is prone to defects such as pores, microcracks and high residual stress, which in turn affects its mechanical properties and service reliability. As an effective post-treatment method, heat treatment can significantly improve the microstructure and comprehensive properties of the coating by promoting atomic diffusion, dislocation recombination and recrystallization. In this paper, the research progress of heat treatment technology on remanufacturing cold sprayed coating at home and abroad is systematically reviewed. The process characteristics and mechanism of traditional heat treatment (such as annealing, solid solution aging) and new heat treatment (such as laser remelting, induction heating, hot isostatic pressing and microwave heat treatment) are emphatically analyzed. The effects of different heat treatment processes on microstructure evolution, defect healing, and mechanical properties of coatings are discussed, and their current status of practical application into the remanufacturing field is summarized. The research shows that the heat treatment process can effectively improve the compactness, strength and toughness, and fatigue resistance of the cold sprayed coating, which provides key technical supports for the life extension and performance recovery of the remanufactured parts.