Investigating the initial cluster formation mechanisms in high-strength 6XXX aluminium alloys by atom probe tomography

Constellium挤压通过开发高强度6xxx系列铝合金，引领了汽车轻量化的发展。目前可以获得屈服应力高达400 Mpa的合金，但为了进一步减轻碰撞管理系统的重量，这些材料需要提高冲击时的能量吸收水平。一种新的制造路线正在开发中，以生产具有增强的可碎性的合金，然而，对于所需的微观结构是如何发展的缺乏基本的了解。围绕最初的聚集机制，特别是当存在高密度位错时，有许多悬而未决的问题。原子探针层析技术是一种独特的显微技术，它能够在原子尺度上可视化和量化团簇初始阶段的尺寸和化学成分，对于了解每个加工阶段对最终微观结构的影响至关重要，牛津大学是英国唯一在这一领域拥有专业知识的机构。该项目的目的是确定微量合金添加对团簇形成的影响，并探索各种工艺参数对团簇动力学的影响。通过与Innoval Technology(英国班伯里)、Constellium和布鲁内尔大学快速成型中心的密切合作，可以评估随后对机械性能的影响，然后将设计出具有改进粉碎性能的精心控制的微观结构。该项目将开发原子探针断层扫描技术，以对一系列加工、处理和合金成分进行直接原子尺度的微结构比较。它还将结合特定部位聚焦离子束样品制备技术和补充显微镜，如透射电子显微镜，以全面表征加工合金的有效性。最终的目标是将这种独特的3D纳米级信息与优化这些铝合金在汽车领域的应用的机械性能/性能相关联。该项目直接涉及EPSRC的主题，制造未来。它还直接促进了EPSRC的优先领域，如：轻量化系统、材料特性和结构完整性与材料行为。它还有可能在这一领域与华威大学和布鲁内尔大学以及捷豹路虎等工业合作伙伴发展更多的合作联系。主题：工程制造未来的物理科学

Constellium extrusion are leading the way for automotive light-weighting by the development of high strength 6XXX series aluminium alloys. Alloys with yield stresses up to 400MPa are currently obtainable, but in order to further reduce the weight of the crash management system, these materials need improved levels of energy absorption on impact.A novel fabrication route is under development to produce alloys with enhanced crushability, however, there is a lack of fundamental understanding of how the desired microstructure develops. There are a number of open questions surrounding the initial clustering mechanisms, particularly when there is a high density of dislocations. The unique capability of the microscopy technique, atom probe tomography, with its ability to visualize and quantify the size and chemistry at the initial stages of clustering at the atomic scale, is essential to understanding the impact of each processing stage on the final microstructure, and Oxford University is the only facility in the UK with expertise in this area.The aims of this project are to identify the effects of trace alloy additions on the cluster formation, and explore the impact of various processing parameters on the clustering kinetics. By working in close collaboration with Innoval Technology (Banbury ,UK), Constellium and the rapid prototyping centre at Brunel University, the subsequent impact on mechanical properties can be assessed, and a carefully controlled microstructure will then be engineered with improved crush properties. The project will develop atom probe tomography techniques to make direct atomic-scale microstructural comparisons across a range of processing treatment and alloy compositions. It will also incorporate site-specific Focused Ion Beam specimen preparation techniques and complementary microscopy, such as TEM, for a holistic characterisation of the effectiveness of the processed alloys. Ultimately the goal is to correlate this unique 3D nanoscale information to optimising the mechanical properties/performance for applications of these Al alloys in the automotive sector.The project directly addresses the EPSRC theme, Manufacturing the Future. It also directly contributes to EPSRC priority areas such as: Lightweight Systems, Materials Characterisation and Structural Integrity and Materials Behaviour. It also has the potential to develop greater collaborative links in this area with the University of Warwick and Brunel University and industrial partners such as Jaguar Land Rover.Themes:EngineeringManufacturing the futurePhysical sciences