Engineering the Anisotropy of Magnesium Alloys for Enhanced Performance

镁是最轻的金属，可用于各种合金形式的承重应用。然而，目前用于成形和成形的加工技术仅限于高温，这会导致高昂的生产成本和负面的环境足迹。该奖项支持基础研究，以提供生产抗断裂镁合金的策略，包括在成形操作期间。与当前思维的一个关键背离是设计这些材料的一个基本特征，即它们属性的方向性，这通常被认为是有害的，因此需要减轻。在数十亿美元的运输业经济中，镁合金的加速插入具有潜在的变革作用。此外，使用这些轻质结构材料将减少燃料消耗和排放，对包括制造业在内的环境产生积极影响。项目活动将为本科生和研究生创造一个跨学科的研究环境，并调查加工和制造方面的教学方法。本研究将阐明镁合金的塑性各向异性与其抗裂性和成形性之间的关系。基本的假设是，镁合金的各向异性可以被设计成具有前所未有的强度和延展性的材料。为了验证这一假设，具有相同化学成分和微观结构但具有不同纹理的材料将以块状和片状形式生产，并对其塑性强度、成形性和断裂性能进行表征。将开发一种基于度量的方法，将塑性各向异性与断裂和成形性的测量相关联。将进行离散位错动力学、连续损伤力学分析和模拟以及微观损伤机制的研究，以进一步了解这种关联的成败。因此，该项目将有助于回答以下重要问题：(I)材料的各向异性本质上是有害的吗？如果不是，如何设计它以增强性能？(2)增强的延展性是否转化为具有成本效益的成形性？(Iii)是否有任何可实现的纹理可导致防止剪切破坏的各向异性类型？(4)各向异性在位错尺度上是如何表现的？对这些问题的调查将遵循一种将材料科学、机械和制造结合在一起的整体方法。

Magnesium is the lightest metal that can be used in load bearing applications in various alloy forms. However, current processing techniques for forming and shaping are limited to elevated temperatures, which drive high production costs and a negative environmental footprint. This award supports fundamental research to provide strategies for producing fracture-resistant Mg alloys, including during forming operations. A key departure from current thinking is to engineer an essential feature of these materials, the directionality of their properties, which is conventionally thought of as deleterious, hence to be mitigated. Accelerated insertion of Mg alloys is potentially transformative in a multi-billion dollar economy of the transportation industry. In addition, use of these lightweight structural materials will lead to reduction in fuel consumption and emissions with a positive impact on the environment, including in manufacturing. The project activities will create an interdisciplinary research environment for both undergraduate and graduate students and investigate teaching methods in processing and manufacturing. The research will elucidate the relationship between the plastic anisotropy of Mg alloys and their fracture resistance and formability. The underlying hypothesis is that the anisotropy of Mg alloys can be engineered to develop materials with unprecedented strength and ductility. To test the hypothesis, materials sharing the same chemical composition and microstructure but having different textures will be produced in bulk and sheet form and characterized for their plastic strength, formability and fracture properties. A metrics-based methodology will be developed for correlating plastic anisotropy with measures of fracture and formability. Discrete dislocation dynamics, continuum damage mechanics analyses and simulations as well as investigations of microscopic damage mechanisms will be carried out to gain further insight into the success or failure of such correlations. The project will therefore help answer important questions such as: (i) Is material anisotropy intrinsically deleterious? If not, how can it be engineered for enhanced performance? (ii) Does enhanced ductility translate into cost-effective formability? (iii) Are there any achievable textures that result in types of anisotropy that prevent shear failure? (iv) How does the anisotropy manifest at dislocation scales? Inquiry into these issues will follow a holistic approach that brings together materials science, mechanics and manufacturing.