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

六方紧密堆积（HCP）金属，如镁和钛，具有提供前所未有的机械性能组合的潜力。然而，HCP金属在工程设计中的成功结合受到其有限塑性的阻碍。最近的研究结果介绍了一种称为“双网格工程”的方法的令人兴奋的潜力，该方法可用于诱导HCP金属的同时强化和增韧。这个设计材料革命和工程我们的未来（DMREF）奖支持基础研究，以制定设计双网格所需的科学框架。综合实验和建模研究活动将寻求发现合金是否可以用于创建高强度，高韧性HCP合金的正确双网格。由此产生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，室温成型性和成本竞争力等特性的材料。一个多样化的学生研究小组将在研究生和本科阶段参与研究项目。该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一项研究合作，探索HCP金属（如镁和钛）中滑移和孪生之间的相互关系。由于细滑移往往会加剧FCC金属的孪生，本研究的目标之一将是评估合金元素对滑移模式的影响，实验和计算使用第一性原理。在辨别出易于孪生的成分后，可以在多晶样品中形成三维孪生网格的纹理将被计算评估。由于滑移和孪晶同时发生，孪晶网将同时阻挡滑移和孪晶，从而增强和增强韧性。从这项研究中获得的知识将用于创建一个称为双网格模块（TMM）的多尺度工具包，该工具包在完全运行时将协调有关滑移孪晶和双孪晶相互作用、处理、双网格微观结构演变和性能的计算。实验验证的TMM将通过提供与工业实践一致的3d双网格加工路径的指导，加速HCP合金的材料发现和设计。沿着材料开发连续体的这一进步将导致低密度、高强度、高韧性合金的广泛使用，从而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.