Innovative thermo-mechanical processing of AA6xxx sheet

推动这项拟议工作的是不断增长的需求，即为汽车行业的轻量化提供具有成本效益的解决方案。目前，由于AA6xxx合金的析出硬化特性，使其在油漆烘烤后具有较高的合金强度和良好的表面质量，因此是制作外墙板材的首选轻合金。尽管在进一步提高AA6xxx汽车板材的沉淀硬化性能方面取得了成就，但这些合金的成形性有限，而且与铝的室温变形相关的回弹也很大。由于具有细晶(FG)组织的铝合金在高温下表现出超塑性行为，制造FG AA6xxx薄板是为了解决这些合金的成形性问题。本研究建立在申请人与Novelis全球技术中心(NGTC)在这一领域的成功合作以及为生产显著提高高温延展性的FG AA6xxx板材而开发的新工艺路线的基础上。本项目的主要目标是：(I)研究AA6xxx合金在热机械加工过程中的细化机制，(Ii)研究合金板材的变形行为，特别是高温行为，以及(Iii)优化加工和性能。UW将与Novelis合作开展这一项目。先进的材料表征技术，可在UW，NGTC，以及在麦克马斯特大学的透射电子显微镜设施，将被用于这项研究。该项目目标的实现将导致引入商业上可行的方法来生产具有优异高温延展性的新一代AA6xxx板材。这项工作的结果还将被用作设计新的温成型工艺的基础，以实现由AA6xxx FG板材制造具有成本效益的蒙皮板材。这些研究成果将对汽车用铝的集成化和高强度、高强度、下一代节油高性能汽车零部件的制造具有重要意义。

The drive for the proposed work is the ever-increasing demand for providing cost-effective solutions forlightweighting in automotive industry. At present, AA6xxx alloys are the light alloys of choice for externalpanels due to their precipitation hardening behaviour, which lead to high alloy strength after paint baking, andexcellent surface quality. Despite achievements in further enhancing the precipitation hardening behaviour ofthe AA6xxx automotive sheets, the alloys suffer from limited formability, as well as large springbackassociated with room temperature deformation of aluminium. As Al alloys with fine-grained (FG)microstructures have demonstrated superplastic behaviour at high temperatures, manufacturing of FG AA6xxxsheets has been sought to provide a solution to the formability issue with these alloys. This investigation isbuilt upon the applicant's successful collaborative work with Novelis Global Technology Centre (NGTC) inthis area and the development of novel processing routes for producing FG AA6xxx sheets with significantlyenhanced high temperature ductility. The key objectives of the present project are: (i) investigating themechanisms of grain refinement during thermomechanical processing of an AA6xxx alloy, (ii) investigatingthe deformation behaviour of the alloy sheets, with particular attention to high temperature behaviour, and (iii)optimizing the processing and properties. UW will collaborate with Novelis to conduct this project. Advancedmaterials characterization techniques, available at UW, NGTC, as well as the TEM facility at McMasterUniversity, will be used for this investigation. The realization of the project's objectives will lead to theintroduction of commercially-viable methods to produce new generation of AA6xxx sheets with excellent hightemperature ductility. The results of this work will also be used as the basis for the design of new warmforming operations for cost-effective manufacturing of skin panels from the AA6xxx FG sheets. The overallresearch will have significant contribution to the integration of aluminium in automobiles and the fabrication oflight, high strength, components for future generation fuel efficient and high performance vehicles.