Industries developing cold spray aim at dense and resistant coatings for component repair. However, as-sprayed 316L coatings display non-equilibrium microstructure and brittle fracture behavior. Improving their mechanical properties requires controlling their microstructure; post-spraying heat treatment is a promising approach. The recovery and recrystallization of coatings were little studied, and heat treatments reported in literature mostly used holding for long time in furnaces, not adapted to on-site repairs. This study aimed at gaining insights into recovery and recrystallization mechanisms of 316L coatings, for a broader range of heat treatment kinetics. A study of powders and as-sprayed coatings was conducted to characterize the initial state. In situ XRD measurements provided input for heat treatment definition. Microscopy, room temperature XRD and hardness measurements allowed to better understand the microstructural evolutions and to select treatments leading to original microstructures. In this work, a variety of microstructures were produced by adapting heat treatment conditions for a given set of spraying parameters. The recrystallization path of the heterogeneous skin-core microstructure of deposited particles, as well as the interaction between grain growth and precipitation was revealed. A novel, optimized fast heat treatment led to a fully recrystallized, fine-grained coating and significantly reduced hardness.

开发冷喷涂的行业旨在为部件修复提供致密且耐腐蚀的涂层。然而，喷涂后的 316L 涂层表现出非平衡微观结构和脆性断裂行为。提高其机械性能需要控制其微观结构；喷涂后热处理是一种有前途的方法。对涂层的恢复和再结晶研究较少，文献报道的热处理大多采用炉内长时间保温，不适应现场修复。本研究旨在深入了解 316L 涂层的恢复和再结晶机制，以实现更广泛的热处理动力学。对粉末和喷涂涂层进行了研究，以表征初始状态。原位XRD 测量为热处理定义提供了输入。显微镜、室温 XRD 和硬度测量可以更好地了解微观结构的演变，并选择产生原始微观结构的处理方法。在这项工作中，通过针对给定的一组喷涂参数调整热处理条件来产生各种微观结构。揭示了沉积颗粒异质皮芯微观结构的再结晶路径，以及晶粒生长和沉淀之间的相互作用。一种新颖的、优化的快速热处理产生了完全再结晶的细晶涂层并显着降低了硬度。