Cost-effective and Environmentally-friendly Manufacturing of Magnesium-based Hybrid Nanocomposite with High Engineering Performance for Next-Generation Automotive Applications

在过去的二十年里，由于其重量轻，镁在车辆中的使用量显着增加。从工程性能的角度来看，镁合金与铝合金和钢相比，由于其较差的机械性能、高温性能、腐蚀性能和磨损性能，其竞争力并不强。最近的研究表明，添加纳米尺寸的增强体提高了力学性能，而基本上不影响镁的塑性。然而，将纳米复合材料应用于真实的工程应用，特别是汽车部件，正面临挑战并且仍处于起步阶段，因为纳米颗粒的高成本和实验制备工艺的复杂性使得它们对高度竞争的汽车工业的吸引力低于微米尺寸增强和常规方法，即，搅拌铸造和/或预成型和挤压铸造。该研究计划的总体目标是开发具有高工程性能的镁基混合纳米复合材料（MHNC）的成本效益和环境友好的制造工艺，以便汽车行业充分利用其独特的性能在下一代结构和动力系统应用中，其不仅承受高循环机械载荷，而且在使用期间需要承受恶劣和腐蚀性环境。在拟议的方案中，计划两个相互交织的流。第一个涉及MHNC的制造通过开发预成型挤压铸造技术与适当的选择微米和纳米尺寸的增强材料，和加工-结构-性能关系的综合评价。该研究计划的第二部分将寻求利用等离子体电解氧化（PEO）工艺的优势，并将其应用于镁基混合复合材料的防腐和耐磨保护。

Magnesium usage has significantly increased in vehicles for the past two decades due to its light weight in nature. From the viewpoint of engineering performance, magnesium alloys are not very competitive owing to their inferior mechanical and high-temperature and corrosion and wear properties in comparison with aluminum alloys and steels. Recent studies show that the addition of nanosize reinforcements enhances the mechanical properties without substantially affecting the plasticity of magnesium. However, applying the nanocomposites for real engineering applications, especially automotive components, is facing challenges and still in infancy because the high cost of nanoparticles and the complexity of experimental preparation processes make them less attractive to the highly competitive automotive industry than micro-size reinforcement and conventional approaches, i.e., stir casting and/or preform and squeeze casting. The overall objective of this research program is to develop cost-effective and environmentally-friendly manufacturing processes for fabrication of magnesium-based hybrid nanocomposite (MHNC) with high engineering performance in order for the automotive industry to make full use of their unique properties in next-generation structural and powertrain applications, which not only suffer high cyclic mechanical loading but also need to sustain harsh and corrosive environment during service. In the proposed program, two intertwined streams are planned. The first involves the fabrication of MHNCs by developing preform-squeeze casting technologies with appropriate selection of micron and nano-size reinforcements, and a comprehensive evaluation of processing-structure-property relationships. A second stream within this program of research will seek to exploit the advantages of the Plasma Electrolytic Oxidation (PEO) process and apply it to the magnesium-based hybrid composites for anti-corrosion and wear protection.