Phenomenological studies on solidification and casting of aluminum and magnesium alloys

减轻重量、提高燃油效率（2025 CAFE: 65.4 MPG）、节约能源、减少碳排放和回收利用已成为全球经济繁荣和高质量生活的基石。轻合金铝（密度：2.70 g/cm3）和镁（密度：1.74 g/cm3）带来了很大的希望，并为汽车行业的新制造工艺的发展提供了空间。然而，仍有一些挑战阻碍了这些合金的使用，因为它们在凝固过程中特别容易形成铸造缺陷（例如，夹杂物、孔隙、热撕裂、错跑、变形）。还需要改进用于发动机系统（例如，发动机缸体，气缸盖）的铝合金的高温性能，以提高运行效率。对于镁合金，具体需求包括开发新的晶粒细化剂，以提高强度和浇注性。

Weight reduction, enhanced fuel efficiency (2025 CAFE: 65.4 MPG), energy conservation, reduced carbon emissions and recycling have become cornerstones for a prosperous global economy and high quality of life. Light alloys of aluminum (density: 2.70 g/cm3) and magnesium (density: 1.74 g/cm3) hold much hope, and provide scope for the development of novel manufacturing processes for the automotive sector. However, there are still some challenges impeding the increased use of these alloys, because they are particularly prone to forming casting defects (e.g., inclusions, porosity, hot tearing, misruns, distortion) during solidification. There is also a need to improve the high temperature performance of aluminum alloys used in engine systems (e.g., engine blocks, cylinder heads) with improved operating efficiency. For magnesium alloys, specific needs include the development of new grain refiners for enhanced strength and castability. This research program seeks to build upon extensive research experience, knowledge and success in castability and characterization of aluminum and magnesium alloys. It envisages a deeper understanding of solidification mechanisms, with a view to reducing the formation of casting defects and improving the mechanical properties of aluminum and magnesium alloys. A new methodology, based on neutron diffraction analysis, will be used to characterize the formation of defects in aluminum and magnesium alloys, specifically for relating the microstructure, strain/stress and hot tear formation. In-situ and ex-situ neutron diffraction will be used for dynamic monitoring of solid fractions of phases and for residual strain/stress mapping. Commercial software will be utilized for modeling heat transfer, hot spots, heat flow, fluid flow and hot tearing in conjunction with neutron analyses and microstructural characterization. The fundamental knowledge gained from both the modeling and the laboratory experiments will be used to explain and predict the formation of casting defects with a view to transferring the knowledge on an industrial scale for foundry and in-service automotive applications. For aluminum alloys, a systematic study relating solidification conditions, heat treatment procedures, mechanical properties and residual strain/stress will be carried out, with a view to eliminating distortions in castings. Novel magnesium grain refiners will be synthesized with appropriate ball milling and sintering for the development of high performance castings. The program will reinforce and enhance an excellent track record of HQP training. The impact of this research will be felt in the 3Es: Energy, environment and economy. Elimination of fuel leakage, increased operating efficiency and extension to new technologies (e.g. linerless engine blocks) will result in increased lightweighting, directly impacting conservation of energy and reducing greenhouse gas emissions. Overall, these advances will reduce recalls (via elimination of distortion) and significantly decreased scrap rate of castings (thru elimination of hot tearing) ensuring enhanced profitability for the Canadian automotive industry, contributing to the revival of the auto economy. As a consequence, they will significantly help in developing standards, policies and overall vision for automobile weights and related emission levels.