高速搅拌摩擦加工制备镁基复合材料成型机理及性能控制

Considering the application requirements and preparation difficulty for lightweight high anti-abrasive and corrosion-resistant magnesium matrix composites, a new method for preparation of magnesium matrix composites using high speed friction stir processing (HSFSP) is proposed. The influence of high rotational speed and fast processing speed on microstructure evolution, anti-abrasive and corrosion-resistant and mechanical properties of composites is investigated in detail. The forming mechanism of magnesium matrix composites prepared by HSFSP is studied. In this project, the microstructure evolution behavior during HSFSP will serve as the breakthrough point. The effect of high rotational speed and fast processing speed on the heat production mechanism and the plastic metal flow behavior for different composite coatings will be established, in addition, the mechanism of forming and property control of magnesium matrix composites with different compositions prepared by HSFSP. The microstructure evolution of different compositions and its impact on anti-abrasive and corrosion-resistant and mechanical properties will be ascertained based on requirements of composition design and processing parameters optimization by experimental analysis and finite element simulation. Moreover, the controlling factors of HSFSP will be determined in order to prepare high performance magnesium matrix composites.

针对轻质高抗磨耐腐蚀镁基复合材料的应用需求和制备技术困难，提出利用高速搅拌摩擦加工制备镁基复合材料的新方法，深入分析高转速和快加工速度对复合涂层微观组织结构演变、防腐耐磨和力学性能的影响规律，研究高速搅拌摩擦加工制备镁基复合材料的成型机理。本项目以高速搅拌摩擦加工过程中微观组织结构演变行为为研究切入点，重点研究高转速和快加工速度对不同成分复合涂层的产热机制和塑性金属流动行为的影响，建立高速搅拌摩擦加工的热原模型和塑性金属流动模型，揭示高速搅拌摩擦加工制备不同成分镁基复合涂层的成型机理及性能调控机制。通过实验研究和有限元模拟，基于性能需求实现涂层成分设计和加工参数优化，阐明高速搅拌摩擦加工不同成分涂层组织演化规律，揭示微观组织结构演变对表面防腐耐磨和力学性能的影响规律，明确高速搅拌摩擦加工的控制因素，实现组织性能可调控的高速搅拌摩擦加工制备高性能镁基复合材料。

针对轻质高抗磨耐腐蚀镁基复合材料的应用需求和制备技术困难，提出利用了高速搅拌摩擦加工制备镁基复合材料的新方法，深入分析了高转速和快加工速度对复合涂层微观组织结构演变、防腐耐磨和力学性能的影响规律，阐明了高速搅拌摩擦加工制备镁基复合材料的成型机理。设计了复合涂层成分，研究复合涂层预制方式，开发了激光熔覆预制与高速搅拌摩擦加工相结合制备技术。主要研究成果有：.(1) 高速搅拌摩擦加工增加热输入，促进塑性金属流动，可显著细化AZ31镁合金加工区平均晶粒，均匀化和弥散化析出相分布，有效改善镁合金表面耐腐蚀性能，一定程度上改善加工区力学性能。.(2) 转速5000 rpm，加工速度125 mm/min，AZ31镁合金单道次高速搅拌摩擦加工区自腐蚀电位提升了21.3%，自腐蚀电流降低了81.5%，抗拉强度提升了1.0%。.(3) 转速3000 rpm，加工速度75 m/min，AZ31镁合金4道次高转速搅拌摩擦加工区自腐蚀电位提升了24.0%，自腐蚀电流降低了64.7%，屈服强度提升了2.4%。.(4) 激光熔敷预制复合涂层，高速搅拌摩擦加工制备的Al-Cu/AZ31和Al-Ti-TiC-CNTs/AZ31镁基复合材料兼具优异的腐蚀性能和表面硬度。自腐蚀电位最大提升了41.8%，自腐蚀电流最小降低了96.6%，表面平均显微硬度最大提升了392.3%。.(5) 开槽镶嵌预制复合涂层，搅拌摩擦加工制备的镁基复合材料腐蚀性能优异。Al-SiC/AZ31镁基复合材料的自腐蚀电位提升了23.7%，自腐蚀电流降低了65.1%。