高性能铝基复合材料冷喷涂固态增材制造成形机理及其强韧性调控

As an effective solid-state processing method, Cold Spraying (CS) has been used to fabricate high-quality metallic or metal matrix composite coatings, as well as the direct, near-net-shape and fast manufacturing of metallic parts, or repairing (re-manufacturing) of worn parts. However, the CSed deposits present a fatal weakness of low ductility, though the strength could be improved by modifying the process parameters, which seriously hinders the wide applications of CS in metallic structural materials. Meanwhile, as a very promising solid-state additive manufacturing technique, the fundamental work on the bonding mechanism and the controlling of strength and ductility of the CSed deposits seriously lacks. Therefore, in this project, the effects of the powder design (e.g. ball milling) and nozzle optimization design before spraying, the process optimization during spraying (e.g. double-stream cold spraying), and the heat treatment or friction stir processing (FSP) after spraying on the microstructure and mechanical properties of the CSed aluminum matrix composites (AMCs) were systematically investigated. The process parameters to yield high strength/ductility materials will be obtained, and the strengthening mechanism will be revealed. Besides, both the external and internal principal factors during heat treatment and FSP which influence the strengthening mechanism will be clarified. Finally, the relationships among the strengthening methods, parameters, and mechanical properties will be established in order to provide experimental and theoretical supports for the precision control of the strength/ductility of the CSed AMCs, and to provide direct guide for its applications in high-quality manufacturing and repairing of parts.

冷喷涂作为一种固态成形方法，不仅可用来制备高性能金属或金属基复合材料涂层，还可以实现零部件快速增材制造与修复再制造。但所制备材料的高强低韧特点严重制约了其在高性能金属结构材料成形中的应用，且作为潜力巨大的固态增材制造方法，尚缺乏对其成形机理及强韧性调控的基础研究。因此，本项目拟研究冷喷涂前粉末设计（粉末预球磨）与喷嘴设计、喷涂过程中工艺优化设计（单/双束喷涂）以及喷后热处理与搅拌摩擦加工处理对冷喷涂铝基复合材料组织结构与力学性能的影响，获得高强韧铝基复合材料的冷喷涂制备工艺，并揭示其强韧化机制，阐明热处理及搅拌摩擦加工处理对冷喷涂铝基复合材料强韧化过程中的外在主导诱因与内在主导机制，构建喷后强韧化方法及参数、强韧化机制及力学性能之间的关系模型，以期为冷喷涂铝基复合材料的强韧性的精确调控提供完善的数据支撑及理论依据，为冷喷涂在高性能金属基复合材料成形与修复中的应用提供理论基础。

冷喷涂作为一种固态成形方法，不仅可用来制备高性能金属或金属基复合材料涂层，还可以实现零部件快速增材制造与修复再制造。但所制备材料的高强低韧特点严重制约了其在高性能金属结构材料成形中的应用，且作为潜力巨大的固态增材制造方法，尚缺乏对其成形机理及强韧性调控的基础研究。因此，本项目研究了粉末设计与后处理对冷喷涂铝基复合材料组织结构与力学性能的影响，获得了高强韧铝基复合材料的冷喷涂制备工艺，并揭示其强韧化机制，阐明了后处理对冷喷涂铝基复合材料强韧化过程中的外在主导诱因与内在主导机制，构建了喷后强韧化方法及参数、强韧化机制及力学性能之间的关系模型，并对比获得了适用于冷喷涂铝基复合材料的力学性能各向异性屈服本构模型。以期为冷喷涂铝基复合材料的强韧性的精确调控提供完善的数据支撑及理论依据，为冷喷涂在高性能金属基复合材料成形与修复中的应用提供理论基础。