DMREF/Collaborative Research: Multiscale Alloy Design of HCP Alloys via Twin Mesh Engineering

镁和钛等六方密排(HCP)金属具有提供前所未有的机械性能组合的潜力。然而，hcp金属的有限塑性阻碍了其在工程设计中的成功应用。最近的研究结果介绍了一种被称为“孪生网格工程”的方法的令人兴奋的潜力。它可用于诱导HCP金属的同时强韧化。这项旨在革新和设计我们的未来的设计材料奖(DMREF)支持基础研究，以制定设计孪生网格所需的科学框架。综合的实验和模型研究活动将寻求发现合金化是否可以用来为高强度、高韧性的HCP合金创造合适的孪晶网状结构。所得到的材料将在节能制造中得到应用，其中需要具有高强度、低密度、室温成形性和成本竞争力的材料。这一奖项将支持加州大学圣巴巴拉分校、欧文分校和戴维斯分校之间的研究合作，以探索HCP金属(如镁和钛)中滑移和孪生之间的相互关系。由于细滑移倾向于加剧面心立方金属中的孪晶，本研究的目标之一将是通过实验和使用第一性原理的计算来评估合金元素对滑移模式的影响。在辨别出容易孪生的成分之后，能够在多晶样品中形成3-D孪生网状结构的织构将通过计算进行评估。由于滑移和孪生同时发生，孪生网眼将阻止滑移和孪生，从而产生强化和韧性。这项研究产生的知识将被用来创建一个多尺度工具包，称为孪生网格模块(TMM)，当完全投入使用时，它将协调关于滑移-孪生和孪生-孪生相互作用、加工、孪生网格微观结构演变和性能的计算。经过实验验证的TMM将通过提供加工路径的指导来创建符合工业实践的三维孪生网格，从而加速HCP合金的材料发现和设计。材料开发连续体的这一进展将导致低密度、高强度、高韧性合金的广泛使用，减轻重量和燃料消耗。

Hexagonal close packed (HCP) metals such as magnesium and titanium have the potential to provide unprecedented combinations of mechanical properties. Successful incorporation of HCP metals into engineering designs is, however, hindered by their limited plasticity. Recent research results have introduced the exciting potential of an approach termed "twin mesh engineering". which can be applied to induce simultaneous strengthening and toughening in HCP metals. This Designing Materials to Revolutionize and Engineer our Future (DMREF) award supports fundamental research to formulate the scientific framework required to design twin meshes. The integrated experimental and modeling research activities will seek to discover if alloying can be used to create the right twin mesh for high strength, high toughness HCP alloys. The resulting materials will have applications in energy efficient manufacturing where materials with attributes such as high strength, low density, room-temperature formability and cost competitiveness are required. A diverse group of student researchers will participate in the research program at both the graduate and undergraduate levels.This award will support a research collaboration between the Universities of California at Santa Barbara, Irvine and Davis to explore interrelationships between slip and twinning in HCP metals, such as magnesium and titanium. As fine slip tends to accentuate twinning in FCC metals, one of the goals of this research will be to evaluate the influence of alloying elements on slip patterns, both experimentally and computationally using first principles. After discerning compositions that twin readily, textures that enable the formation of 3-D twin meshes in polycrystalline samples will be assessed computationally. Since slip and twinning occur concomitantly, twin meshes will block both slip and twins, leading to strengthening and toughness. The knowledge generated from this research will be used to create a multiscale tool kit, called the twin-mesh module (TMM), which when fully operational will coordinate calculations pertaining slip-twin and twin-twin interactions, processing, twin-mesh microstructure evolution, and properties. Experimentally validated TMM will accelerate materials discovery and design of HCP alloys by providing guidance on processing pathways to create 3-D twin meshes that are consistent with industrial practices. This advancement along the Materials Development Continuum will lead to expanded use of low-density, high strength, high toughness alloys, reducing weight and fuel consumption.