DMREF: Collaborative Research: GOALI: Localized Phase Transformation (LPT) Strengthening for Next-Generation Superalloys

非凡性能这项旨在革新和设计我们未来的设计材料(DMREF)学术与工业联系机会(GOALI)奖支持一项综合的实验和计算努力，以加速发现具有优异高温蠕变性能的新型镍基高温合金，但很可能会被传统的试错法遗漏。镍基高温合金是实现高温结构材料的关键，这些材料决定了各种航空航天和陆基发电系统(如燃气轮机)的效率和碳足迹。这一努力是材料基因组倡议(MGI)和综合计算材料工程倡议(ICME)倡议下国家努力的组成部分。高温合金的开发将首次由计算建模、机械信息和关键实验验证，这些实验涉及材料加工的新组合方法和最先进的表征技术。由于未来的材料研发活动需要大幅缩短时间和成本周期，必须将计算材料研究与关键实验相结合，因此该研究项目将直接为研究生做好准备，立即为MGI/ICME在行业中的成功做出贡献。此外，对参与材料开发的研究人员的培训计划将加快新方法在工业中的实施，从而提高美国材料技术员的效率。在教育推广方面，目前的DMREF计划将聘请本科生研究人员作为导师，开展K-12工程推广活动，鼓励不同种族背景的高中生进入科学和工程学科。DMREF目标项目将利用一种新的设计战略，利用局部相变(LPT)现象来颠覆性地改善镍基高温合金的高温蠕变性能。LPT只出现在扩展的缺陷处，并且局部限制在这些缺陷处。通过集成复杂的多尺度计算模型、先进的材料表征技术以及材料加工和性能评估的组合和加速方法，该项目将：(A)通过高通量DFT蒙特卡罗计算搜索高维合金成分空间以寻找LPT的发生，并通过新的组合方法验证DFT预测，以快速生产合金，结合先进的电子显微镜和原子探针层析；(B)利用以DFT计算为输入的相场模拟，建立缺陷类型(层错、反相界、孪晶、位错及其网络)与LPT本质之间的联系；(C)定量确定LPT对操作变形机制的影响，并开发基于物理的变形模型，利用相场法和对机制敏感的晶体塑性模型相结合的方法来捕捉这些影响，这将使能够针对多晶蠕变实验进行直接验证；以及(D)采用新的工艺路线，通过LPT稳定高位错/孪晶密度微结构，从而为部署到高温合金中提供新的强化机制。该项目的目标合作伙伴GE Research将通过提供单晶和多晶形式的高质量合金来回应合金建议。这样的综合研究工作将大大提高新高温合金发现和开发的最新水平，并有望在合金设计中产生新的科学。对高温合金的关注将对包括航空航天、交通和能源在内的一系列先进技术领域产生显著影响。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。

Extraordinary Properties This Designing Materials to Revolutionize and Engineer our Future (DMREF) Grant Opportunity for Academic Liaison with Industry (GOALI) award supports an integrated experimental and computational effort to accelerate the discovery of new typs of Ni-base superalloys that will have superior high-temperature creep performance, but most likely will have been missed by the traditional trial-and-error method. Ni-base superalloys are critical enabling high-temperature structural materials that determine the efficiency and carbon footprint of a wide range of aerospace and land-based power generation systems such as gas turbines. This effort is an integral part of the national efforts under the Materials Genome Initiative (MGI) and the Integrated Computational Materials Engineering (ICME) initiative. For the first time, superalloy development will be led by computational modeling, mechanistically informed and validated by critical experiments involving novel combinatorial methods for materials processing and state-of-the-art characterization techniques. Because future materials R&D activities, requiring substantially reduced time and cost cycles, must integrate computational materials research with critical experiments, this research project will directly prepare graduate students to immediately contribute to the success of MGI/ICME in industry. Additionally, the training programs for researchers involved in materials development will accelerate the implementation of the new methodology in industry, resulting in increased effectiveness of the US materials technologists. Regarding educational outreach, the present DMREF program will engage undergraduate researchers as mentors who develop K-12 engineering outreach activities encouraging high school students with diverse ethnic backgrounds to enter science and engineering disciplines This DMREF GOALI project will exploit a new design strategy that utilizes a localized phase transformation (LPT) phenomenon to disruptively improve the high-temperature creep performance of Ni-based superalloys. LPTs occur only at extended defects and are confined locally at these defects. By integrating sophisticated computational models, at multiple scales, highly advanced materials characterization techniques, and combinatorial and accelerated methods of materials processing and property evaluation, this project will (a) search the high-dimensional alloy composition space for the occurrence of LPT by high-throughput DFT Monte Carlo calculations, and validate the DFT predictions by novel combinatorial methods to rapidly produce alloys, coupled with advanced electron microscopy and atom probe tomography; (b) establish the connection between defect type (stacking fault, anti-phase boundaries, twins, dislocations and their networks) and the nature of LPT using phase field simulations with the DFT calculations as inputs; (c) quantitatively determine the effect of LPT on the operative deformation mechanisms and develop physics-based deformation models that capture these effects using a combination of the phase field method and a mechanism-sensitive crystal plasticity model, which will enable direct validation against polycrystalline creep experiments; and (d) employ novel processing routes to stabilize high dislocation/twin density microstructures by LPT, thereby providing a new strengthening mechanism for deployment to superalloys. The GOALI partner of this project, GE Research, will respond to alloy recommendations by providing high quality alloys in single crystal and polycrystal forms. Such an integrated research effort will raise significantly the state-of-the-art in the discovery and development of new superalloys and is expected to result in new science in alloy design. The focus on superalloys will have a marked impact on a broad range of advanced technological areas including aerospace, transportation and energy.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.