Excess Vacancy Enabled Transformations in Light Metal Alloys

过剩的空位促进了轻金属合金的转变

• 批准号: 2320355
• 负责人: Michael Falk
• 金额: $ 69.01万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2320355&HistoricalAwards=false
• 关键词: Excess; Vacancy; Enabled; Transformations; Light

NON-TECHNICAL SUMMARYInnovating processes for lightweight metal alloy manufacture advances public welfare and secures the national defense by enabling efficient production of new materials that provide strength without adding weight in applications from vehicles and protective equipment to space exploration. This award supports basic scientific studies regarding how atomic structures respond to extreme conditions of temperature and strain that result in defects called vacancies, where atoms are missing from the metal’s crystal structure. This research advances the understanding of why and how vacancies cluster with solute atoms that differ from the primary metal, gathering into small bubbles called voids and encouraging the formation of strengthening particles.Multiple experimental techniques are used: positively charged particles are used to measure defects; atom probe reveals locations of different elements in the crystal structure; and electron microscopy images show larger scale features such as voids. Simulations predict how vacancies, solute and voids interact to better interpret the experimental data. These simulations also provide estimates of how the rate at which voids form, varies with temperatures, vacancy densities, and solute chemistries and densities. Experimental data are used to guide the choices of simulations and to check the validity of the simulations. In the process, this work advances simulation capabilities.This project engages undergraduates from Morgan State University, a nearby historically Black university, to foster the success of a newly emerging program that provides access to engineering degrees not currently offered at that university. The investigators also are planning to host an “Extreme Vacancy Engineering” workshop.TECHNICAL SUMMARYThe proposed research program aims to accelerate the development of new light alloys and processing routes by expanding our fundamental understanding of how vacancy supersaturation alters the thermodynamics of vacancy clustering, vacancy-solute complex formation, and void nucleation in ways that promote solute clustering and intermetallic precipitation. Alloys over a range of compositions are subjected to quenching and deformation to enhance vacancy densities in a controlled manner. Analysis is performed using an emerging computational methodology, transition interface sampling, coupled with targeted characterization using positron annihilation spectroscopy, atom probe tomography, and transmission electron microscopy in concert with molecular dynamics and Monte Carlo simulation. Experiments are leveraged to guide simulations and simulations to interpret experiments. The work aims to build a thermodynamic understanding for key processes in the form of free energy pathways that eschew classical nucleation theory assumptions in out-of-equilibrium systems.This research program engages undergraduates from Morgan State University, a nearby HBCU, to foster the success of a newly emerging 3+2 program that opens new pathways into materials-related engineering majors. A workshop on “Extreme Vacancy Engineering” is also anticipated to promote an emerging field of materials processing and designThis 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.

轻巧金属合金制造业的非技术总结工艺通过公共福利提升，并通过有效生产新材料来确保国防，从而在不增加车辆和受保护设备的应用到太空探索的情况下提供强度。该奖项支持有关原子结构如何响应温度和劳累条件的基础科学研究，从而导致称为空缺的缺陷，其中金属晶体结构缺少原子。这项研究促进了理解为什么和如何使用与原代金属不同的固体原子聚类，聚集成一个称为空隙的小气泡并鼓励形成增强颗粒的小气泡。使用多种实验技术：使用带正电荷的颗粒来测量缺陷；原子探针揭示了晶体结构中不同元素的位置。电子显微镜图像显示了较大规模的特征，例如空隙。模拟预测空位，可溶性和空隙如何相互作用以更好地解释实验数据。这些模拟还提供了估计空隙形成速率，温度，空缺密度以及可溶性化学和密度的速率的估计。实验数据用于指导模拟的选择并检查模拟的有效性。在此过程中，这项工作提高了仿真能力。该项目聘请了摩根州立大学（Morgan State University）是一所历史悠久的黑人大学的本科生，以促进新出现的计划的成功，该计划提供了该大学目前未提供的工程学位的访问权。 The investigators are also planning to host an “Extreme Vacancy Engineering” workshop.TECHNICAL SUMMARYThe proposed research program aims to accelerate the development of new light alloys and processing routes by expanding our fundamental Understanding of how vacancy supersaturation alters the thermodynamics of vacancy clustering, vacancy-solute complex formation, and void nucleation in ways that promote solid clustering and intermetallic precipitation.一系列成分的合金受到淬灭和变形，以受控的方式增强空缺密度。使用新兴的计算方法，过渡界面采样，并使用阳性歼灭光谱，原子探针层析成像以及传输电子显微镜与分子动力学和蒙特卡洛模拟一起进行靶向表征。利用实验来指导模拟和模拟来解释实验。这项工作旨在以自由能通道的形式对关键过程建立热力学理解，该过程避免了经典的核理论假设，该假设在超平衡系统中。该研究计划吸引了HBCU附近的摩根州立大学的本科生，以促进新培养的3+2个新途径的成功，该计划将新的3+2个新的途径推向了新的PATER，将新的PATH培养为材料优惠的Eromperering Majerors。预计还预计，还将在“极端空缺工程”的研讨会上促进新兴的材料处理领域和设计奖，这反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，通过评估被认为是珍贵的支持。