EAGER: An Innovative Modelling Approach to Predict Non-Equilibrium Phases Produced in Metal Additive Manufacture Processes

EAGER：一种预测金属增材制造过程中产生的非平衡相的创新建模方法

• 批准号: 1841220
• 负责人: Judy Schneider
• 金额: $ 20.87万
• 依托单位: University of Alabama in Huntsville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2020-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1841220&HistoricalAwards=false
• 关键词: EAGER; Innovative; Modelling; Approach; Predict

This EArly-concept Grant for Exploratory Research (EAGER) project will develop a new and untested approach toward modeling of the non-equilibrium behavior of complex metal alloys in terms of the evolution of their atomic arrangement. In additive manufacturing of metals, various process maps are used to guide the selection of time and temperature to produce the desired microstructure to meet the required mechanical properties or performance. Most metal fabrication processes occur at equilibrium, with known conditions of temperature and time. In contrast, the laser-engineered net shaping and related additive manufacturing processes builds a part by depositing the metal as small molten drops which are rapidly and repeatedly heated and solidified layer by layer. While this greatly reduces the time, cost, and weight in the direct build of a complex multi-part assembly, the rapid and repeated melting and re-solidification in additive manufacturing results in a variety of difficult-to-predict non-equilibrium phases that lead to uncertainty in the resulting microstructure and mechanical properties. At present, expensive trial-and-error experimental studies form the basis for such microstructural development. This work has the potential to realize non-equilibrium maps that will enable the full potential of additive manufacturing, thereby advancing the processing of industrially significant alloys to empower new applications in the biomedical, aerospace, chemical, and energy industries. As a result, this work will enhance the US economy, society, and global competitiveness in manufacturing. To realize the full potential for reducing fabrication costs through the use of additive manufacturing, viable thermodynamic and kinetic road maps need to be generated for predicting the microstructures to guide and optimize the processing parameters to optimize the material performance. The thermodynamics and kinetics of Inconel 718, a nickel based superalloy, will be modeled from first-principles calculations and data-intensive statistical mechanics approaches. The temporal evolution of atomic arrangements at given temperature and chemical potentials, will be modeled based on the diffusion through vacancy mechanism. The change of atomic configuration will be simulated under an adiabatic approximation, averaging out fast degrees of freedom such as electronic and lattice vibrations on the hopping time scale. Then, the temporal evolution of atomic arrangement will be modeled by a series of events: switching a vacancy with one of its nearest neighbor atoms, which is equivalent to the hopping of the switched atom to the vacant site. Integrating numerical predictions with experimentally observed microstructural responses will rapidly verify the proposed approach.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.

这个早期概念探索性研究拨款(AGER)项目将开发一种新的未经测试的方法，根据复杂金属合金的原子排列的演变来模拟其非平衡行为。在金属的添加制造中，各种工艺图被用来指导时间和温度的选择，以产生满足所需机械性能或性能的所需显微组织。大多数金属加工过程是在平衡状态下进行的，已知的温度和时间条件。相比之下，激光设计的净成形和相关的添加剂制造工艺通过将金属沉积成小熔滴来制造零件，这些小熔滴被快速和重复地加热并逐层凝固。虽然这大大减少了直接建立复杂的多部件组件的时间、成本和重量，但添加剂制造中快速和重复的熔化和再凝固导致了各种难以预测的非平衡相，从而导致由此产生的组织和机械性能的不确定性。目前，昂贵的反复试验研究构成了这种微结构发展的基础。这项工作有可能实现非平衡图，从而充分发挥添加剂制造的潜力，从而促进具有重要工业意义的合金的加工，使其在生物医学、航空航天、化工和能源行业获得新的应用。因此，这项工作将增强美国经济、社会和制造业的全球竞争力。为了充分发挥通过使用添加剂制造降低制造成本的潜力，需要生成可行的热力学和动力学路线图来预测微结构，以指导和优化工艺参数，以优化材料性能。镍基高温合金Inconel718的热力学和动力学将由第一性原理计算和数据密集型统计力学方法模拟。在给定的温度和化学势下，原子排列的时间演化将基于通过空位的扩散机制来模拟。原子构型的变化将在绝热近似下模拟，在跳跃时间尺度上平均出快速自由度，如电子和晶格振动。然后，原子排列的时间演化将由一系列事件来模拟：空位与其最近的邻近原子之一交换，这相当于被交换的原子跳跃到空位。将数值预测与实验观察到的微观结构响应相结合，将迅速验证所提出的方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。