Collaborative Research: Interface enabled plasticity in high-strength Co-based intermetallics

合作研究：高强度钴基金属间化合物的界面塑性

• 批准号: 2210152
• 负责人: Xinghang Zhang
• 金额: $ 37.28万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2210152&HistoricalAwards=false
• 关键词: Collaborative; Research; Interface; enabled; plasticity

Nontechnical SummaryThe design of high strength and high deformability materials is critical for next-generation structural applications that can transform the national defense systems and industries such as aerospace, automotive, and energy. Intermetallics, with their remarkable properties of high mechanical strength and high melting temperatures, are excellent candidates for these applications. However, conventional intermetallics are very brittle at room temperature, which adversely impacts their potential as structural materials. Although intermetallics have been the subject of active research in recent decades, achieving room temperature plasticity while retaining high strength has been a major challenge. Prior approaches to improve plasticity in intermetallics have primarily focused on improving fracture resistance by grain refinement, improving grain boundary cohesive strength and introducing second phase particles. The investigators’ preliminary studies reveal that CoAl nanocomposites with unconventional thick grain boundaries exhibit ultra-high strength and high deformability. However, the fundamental mechanisms underpinning these remarkable properties remain unclear. Through the synergistic combination of nanofabrication, in situ nanomechanical testing and atomistic modeling, they elucidate the deformation mechanisms in core/shell nanocomposites at an atomistic level. The close collaboration among the investigators enable graduate and undergraduate research students to develop a wholesome foundation in both experiments and simulations through biweekly videoconferences, and annual visits to counterpart institutions. Graduate students also access advanced microscopy facilities housed within the Center for Integrated Nanotechnologies managed by Los Alamos National Lab and Sandia National Lab. The investigators recruit minority students for the proposed project. The specimens fabricated from this project are tested at NASA’s International Space Station. Technical SummaryThe goal of this project is to understand the mechanical behavior of nanocrystalline (NC) intermetallics with a novel core/shell architecture that endows them with simultaneous high strength and unprecedented deformability at room temperature. The investigators explore the deformation mechanisms in core/shell composites via integrated in situ nanoindentation and atomistic simulations to elucidate grain boundary dominated plasticity in nanocrystalline intermetallics, quantify the impact of thick interfaces on strengthening and deformability of CoAl intermetallics in core/shell nanocomposites, and understand the high temperature deformation mechanisms of core/shell nanocomposites by combining in situ microcompression tests in SEM and molecular dynamics simulations. The research program significantly advances the understanding of the deformation mechanisms, design and fabrication of intermetallics with unconventional core/shell architecture for critical structural applications. This work furnishes atomistic insights into “thick” grain boundary as novel motifs for extraordinary mechanical properties that open up avenues for the rational design of other intermetallics through grain boundary engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要高强度和高变形材料的设计对于下一代结构应用至关重要，这些应用可以改变国防系统和航空航天、汽车和能源等行业。金属间化合物具有高机械强度和高熔化温度的卓越性能，是这些应用的绝佳选择。然而，传统的金属间化合物在室温下非常脆，这对其作为结构材料的潜力产生了不利影响。尽管金属间化合物近几十年来一直是活跃研究的主题，但在保持高强度的同时实现室温塑性一直是一个重大挑战。现有的提高金属间化合物塑性的方法主要集中在通过晶粒细化、提高晶界内聚强度和引入第二相颗粒来提高断裂抗力。研究人员的初步研究表明，具有非常规厚晶界的CoAl纳米复合材料表现出超高强度和高变形能力。然而，支撑这些非凡特性的基本机制仍不清楚。通过纳米加工、原位纳米力学测试和原子建模的协同组合，他们在原子水平上阐明了核/壳纳米复合材料的变形机制。研究人员之间的密切合作使研究生和本科生能够通过每两周一次的视频会议和每年对对应机构的访问，在实验和模拟方面打下良好的基础。研究生还可以使用由洛斯阿拉莫斯国家实验室和桑迪亚国家实验室管理的集成纳米技术中心内的先进显微镜设施。调查人员为拟议项目招募少数民族学生。该项目制造的样本在美国宇航局国际空间站进行了测试。 技术摘要该项目的目标是了解具有新颖核/壳结构的纳米晶（NC）金属间化合物的机械行为，该结构赋予它们在室温下同时具有高强度和前所未有的变形能力。研究人员通过集成原位纳米压痕和原子模拟来探索核/壳复合材料的变形机制，以阐明纳米晶金属间化合物中晶界主导的塑性，量化厚界面对核/壳纳米复合材料中CoAl金属间化合物的强化和变形能力的影响，并通过结合 SEM 和分子动力学模拟中的原位微压缩测试。该研究项目显着增进了对关键结构应用中具有非常规核/壳结构的金属间化合物的变形机制、设计和制造的理解。这项工作提供了对“厚”晶界的原子论见解，作为非凡机械性能的新颖主题，为通过晶界工程合理设计其他金属间化合物开辟了途径。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。