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

由于镁的重量很轻，在过去的二十年里，它在汽车上的使用量大幅增加。从工程性能的角度来看，与铝合金和钢相比，镁合金的机械性能、高温性能和腐蚀磨损性能较差，不具有很强的竞争力。最近的研究表明，纳米增强体的加入提高了镁的力学性能，而不会对镁的塑性产生实质性的影响。然而，将纳米复合材料应用于实际工程应用，特别是汽车零部件，面临着挑战和仍处于起步阶段，因为纳米颗粒的高昂成本和复杂的实验制备过程使其对竞争激烈的汽车行业的吸引力低于微米级增强体和传统方法，即搅拌铸造和/或预制件和挤压铸造。这项研究计划的总体目标是开发具有高工程性能的镁基混杂纳米复合材料(MHNC)的低成本和环境友好的制造工艺，以便汽车行业在下一代结构和动力总成应用中充分利用它们的独特性能，这些应用不仅要承受高循环机械载荷，而且需要在使用过程中承受恶劣和腐蚀的环境。在拟议的计划中，计划了两条相互交织的溪流。第一个涉及通过发展预制件挤压铸造技术，适当选择微米和纳米增强体，以及对工艺-结构-性能关系的综合评估来制造MHNC。该研究计划中的第二个方向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杂复合材料的防腐和耐磨保护。*该项目的结果将保持加拿大在生产轻质镁基工程部件方面的世界领先地位，因为加拿大目前拥有世界上最大的镁铸件生产商--安大略省的子午线轻质技术公司。为潜在的先进部件开发新技术的成功将导致加拿大镁部件发货量的增加，以及加拿大增值镁产品在世界范围内的扩大使用。

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. ***The outcome of the project will maintain Canada as a world leader in producing light weight magnesium-based engineering components since Canada is presently hosting the largest magnesium casting producer in the world, Meridian Lightweight Technologies in Ontario. The success in the development of new technologies for potential advanced components will lead to an increase in magnesium component shipment in Canada as well as an expansion of world-wide use of Canadian value-added magnesium products.