Development of Aluminum Casting and FSW Technologies for Next-Generation Automotive Powertrains

为了提高车辆的燃料效率，铝（Al）合金是汽车动力系统部件（例如电动车辆的发动机缸体和电池托盘）的潜在候选者。轻质铝合金在广泛的工作温度范围内具有良好的机械强度，使其成为动力总成应用的绝佳选择。然而，加工过程中残余应力的产生限制了Al的功效。发动机缸体几何形状复杂，铸件冷却速度不同，各部位热膨胀不匹配，是产生残余应力的根本原因。搅拌摩擦焊接（FSW）部件中的残余应力也显著地使电池托盘的开发和生产复杂化。残余应力可以通过热处理如固溶、退火和人工时效来降低。然而，有效的处理技术的发展，经常受到不一致的微观结构，不可靠的（或不可验证的）参数在最终元素分析（FEA），并在直接实验测量的残余应力分布的困难。 该项目将建立在Nemak Canada和申请人的UBC团队之间成功的NSERC Engage资助项目的基础上，该项目对直列6缸发动机缸体原型的应力，微观结构，相分析和机械性能进行了研究。 目前拟议的项目将集中在应力，微观结构演变和新架构的I6发动机缸体和FSW电池托盘的性能的综合研究。这项新研究涉及使用中子衍射的应力扫描，FEA及其使用实验数据的验证。在适用性测试中，原型样品将在我们独特的现场测试设备上经受真实的寿命载荷-温度服务条件。研究范围包括采用不同铸造、热处理和焊接参数生产的I6块和电池托盘。 两名HQP将通过该项目接受培训。Nemak将把这些成果纳入其运营中，使安大略I6区块的生产成为可能，并增加加拿大铝业的供应订单。

With an effort to improve vehicle fuel efficiency, aluminum (Al) alloys are potential candidates for automotive powertrain components such as engine blocks and battery trays for electrical vehicles. Lightweight Al alloys have good mechanical strength at wide range of operating temperatures, making them excellent choices for powertrain applications. However, generation of residual stresses during processing limits Al's efficacy. The root cause of residual stress is the differences in cooling rate in casting of engine block due to its complex geometry, and thermal expansion mismatch in various parts of the block. Residual stress in friction-stir welded (FSW) components also significantly complicates development and production of battery trays. Residual stresses can be reduced by heat treatment such as solutionizing, annealing, and artificial ageing. The development of efficient treatment technologies, however, is often hindered by inconsistent microstructure, unreliable (or non-verifiable) parameters used in final element analysis (FEA), and difficulties in direct experimental measurements of residual stress profiles. This project will build upon a successful NSERC Engage-funded project between Nemak Canada and the applicant's UBC team in which stress, microstructures, phase analysis, and mechanical properties were investigated for prototypes of inline-6 engine blocks. The currently proposed project will focus on comprehensive studies on stress, microstructure evolution, and properties for a new-architecture I6 engine block and FSW battery tray. The new study involves stress scan using neutron diffraction, FEA, and its validation using the experimental data. In a fitness-for-service test, the prototype samples will be subjected to the real life load-temperature service conditions at our unique in-situ testing apparatus. The scope of studies includes I6 blocks and battery trays produced with varying casting, heat treatment, and welding parameters. Two HQP will be trained through this project. Nemak will incorporate the results into its operations, enabling production of I6 block in Ontario and leading to increase of supply orders to the Canadian aluminum industry.