Atomistic Studies of Concentrated Multicomponent Nickel-Based Alloys Utilizing Atom-Probe Tomography and Vacancy-Mediated Lattice Kinetic Monte Carlo Simulations

利用原子探针断层扫描和空位介导的晶格动力学蒙特卡罗模拟对浓多组分镍基合金进行原子研究

• 批准号: 1610367
• 负责人: David Seidman
• 金额: $ 45万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1610367&HistoricalAwards=false
• 关键词: Atomistic; Studies; Concentrated; Multicomponent; Nickel

Non-Technical AbstractThis research program is focused on how phase separation occurs in nickel-aluminum based alloys, which are the physical bases of all nickel-based superalloys and which may contain up to 12 different alloying elements, with each element serving a particular purpose. Nickel-based superalloys are utilized for turbine blades and disks, which are at the heart of both military and commercial jet engines as well as natural gas-fired turbine engines that produce electricity, and which operate at extremely elevated temperatures. To study these materials at an atomic scale in this technologically important class of alloys, extensive utilization will be made of the Northwestern University Center for Atom-Probe Tomography. Atom-Probe Tomography is a unique technique that allows characterizing materials at the sub-nano to nanoscale. Applying this technique to nickel-aluminum based alloys will allow understanding the development of the final microstructure, which is of great significance and technological importance for controlling the physical and mechanical properties of a material at microscopic and macroscopic length scales. This work will help train the next generation of materials scientists in this state of the art technique. Technical AbstractThe kinetic pathways in the different stages of alloy phase separation (nucleation, growth and coarsening) of concentrated multicomponent nickel-based supersaturated solid-solutions are critical for understanding the development of the final microstructure, which is of great significance and technological importance for controlling the physical and mechanical properties of a material at microscopic and macroscopic length scales. To study the temporal evolution of phase separation, the PI will perform correlative experiments utilizing ultraviolet laser-assisted atom-probe tomography (APT) and vacancy-mediated lattice-kinetic Monte Carlo (LKMC) simulations, which permit understanding this evolution on an atomic scale. This work will also employ microhardness measurements and transmission electron microscopy experiments. The temporal evolution is studied starting with the clustering of atoms to form embryos exhibiting short-range order (SRO), which are the precursors of stable nuclei (precipitates); thus, allowing study of SRO and then precipitates with long-range order (LRO) and observation of growth and coarsening. All of the 10 plus physical parameters, for describing the temporal evolution, are measured via APT and simulated via LKMC simulations. Additionally, the PI will study the evolution during the quasi-steady coarsening regime and compare these results with the Philippe-Voorhees (P-V) mean-field modeling of multicomponent alloys (2013) for selected ternary and quaternary nickel-based alloys, which involves the use of both thermodynamic and mobility data bases. This will yield a realistic approach to quasi-stationary coarsening of a polydispersed distribution of precipitates embedded in a matrix. This multipronged experimental and simulation approach yields information at the atomic scale through the continuum length scale.

非技术摘要本研究项目的重点是镍铝基合金中相分离是如何发生的，镍铝基合金是所有镍基高温合金的物理基础，可能含有多达12种不同的合金元素，每种元素都有特定的用途。镍基超耐热合金用于涡轮机叶片和盘，其是军用和商用喷气发动机以及产生电力的天然气燃烧的涡轮机发动机的核心，并且其在极高的温度下操作。 为了在原子尺度上研究这类具有重要技术意义的合金中的这些材料，将广泛利用西北大学原子探针断层扫描中心。原子探针断层扫描是一种独特的技术，可以在亚纳米到纳米尺度上表征材料。 将该技术应用于镍铝基合金将允许理解最终微观结构的发展，这对于在微观和宏观长度尺度上控制材料的物理和机械性能具有重要意义和技术重要性。这项工作将有助于培养下一代材料科学家在这种最先进的技术。多组分镍基过饱和固溶体合金相分离不同阶段（形核、生长和粗化）的动力学路径对于理解最终微观结构的发展至关重要，这对于在微观和宏观尺度上控制材料的物理和机械性能具有重要意义和技术重要性。为了研究相分离的时间演变，PI将利用紫外激光辅助原子探针层析成像（APT）和空位介导的晶格动力学蒙特卡罗（LKMC）模拟进行相关实验，从而可以在原子尺度上理解这种演变。 这项工作还将采用显微硬度测量和透射电子显微镜实验。时间演化的研究开始与原子的集群，形成胚胎表现出短程有序（SRO），这是稳定的核（沉淀物）的前体，因此，允许研究SRO，然后沉淀物与长程有序（LRO）和观察的增长和粗化。所有的10+物理参数，用于描述的时间演变，通过APT测量和模拟通过LKMC模拟。此外，PI将研究准稳态粗化状态期间的演变，并将这些结果与选定的三元和四元镍基合金的多组分合金的Philippe-Voorhees（P-V）平均场模型（2013）进行比较，其中涉及使用热力学和迁移率数据库。 这将产生一个现实的方法，准静态粗化的多分散分布的沉淀物嵌入在一个矩阵。这种多管齐下的实验和模拟方法产生的信息在原子尺度上通过连续长度尺度。