激光选区熔化成形微纳复相结构增强铝基复合材料的组织调控机理及其强韧化机制研究

激光选区熔化技术（SLM）所制备的高性能陶瓷增强型铝基复材在航空航天等关键领域有重要应用，但协同提升复材的强韧性已成为推动该类材料深入应用的瓶颈。目前，通过增强相有序结构化分布和微纳复相复合实现强韧化的理念已在传统铝基复合材料设计中得到肯定。因而，本项目拟以TiB2/Al-5Cu为研究对象，创新地将这两种理念同时运用到高强韧性SLM TiB2/Al-5Cu的研发中。通过深入研究成形过程中TiB2迁移行为、晶粒-长大机制、各相分布规律和时效热-动力学机制等问题，实现成形工艺和后期热处理对近全致密SLM TiB2/Al-5Cu复合材料的结构化微纳复相组织的调控，并阐明调控机制；基于跨尺度力学分析，通过研究相/基界面交互作用、应力下裂纹演化规律，微结构韧化作用等问题以提升材料高强韧性，并基于混合定律揭示强韧化机制，为高性能SLM铝基复材设计和制造提供理论和实验依据。

High-performance aluminum matrix composites (AMCs) reinforced with ceramics fabricated by selective laser melting (SLM) have important applications in key fields like aeronautics and astronautics. However, the synergistic improvement of strengthening-toughening properties of SLM AMCs has become a bottleneck for their further applications. At present, the concept of the architectural design and micro/nano multi-phases modification for the improved strengthening-toughening properties has been affirmed in the traditional AMCs design. Therefore, this project will focus on TiB2/Al-5Cu fabricated by SLM and innovatively apply these two concepts together to study SLM TiB2/Al-5Cu with high strengthening-toughening properties. According to the research on the migration behavior of TiB2 phase, grain-growth mechanism, the phase distribution, and the aging thermo-dynamic mechanism, the architectural microstructure with micro/nano multi-phases of near-fully dense SLM TiB2/Al-5Cu composites can be tailored by the processing parameters and post-heat treatment, thereby clarifying the adjustment rules for the specific microstructure. According to the trans-scale mechanical analyses, research on some problems (like the interfacial interaction between the reinforcements and the matrix, the crack evolution under the stress and toughness caused by architectural toughness) is helpful to improve strengthening-toughening properties, thereby clarifying the strengthening-toughening mechanisms based on the rule of mixture. This project can provide a scientific and experimental fundamental on the design and processing of SLM AMCs with high performance.