Diffusion in BCC multi-principal element alloys from experiment and ab initio: Impact of thermal vibrations and chemical complexity

从实验和从头算起 BCC 多主元素合金中的扩散：热振动和化学复杂性的影响

• 批准号: 509804947
• 负责人: Professor Dr. Sergiy Divinski
• 金额: --
• 依托单位: Institut für Materialphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/509804947?language=en
• 关键词: Diffusion; BCC; multi; principal; element

Diffusion in concentrated alloys, especially in so-called multi-principal element alloys (MPEAs), attracts increasing attention due to advanced technological applications. Such alloys exhibit unique features prominently sluggish diffusion that critically affect various materials properties, e.g., microstructure evolution, phase stability, creep behavior, radiation tolerance. The unique features of MPEAs generally originate from the significant chemical complexity which, at the same time, brings about tremendous challenges for both experimental and theoretical studies. Theoretically, the role of lattice thermal vibrations in combination with the strong heterogeneity of local environments and their impact on diffusion in MPEAs are far from being understood, impeding a quantitative, and sometimes even a qualitative, prediction of diffusivities. Based on a concerted effort of teams from Stuttgart (simulation) and Münster (experiment) both established leaders in their respective research fields and connected with each other through a long-standing collaboration—the present project aims at developing accurate and versatile approaches to investigate and fundamentally understand diffusion in complex MPEAs. Utilizing a combination of an advanced radiotracer technique together with several highly accurate ab initio-informed simulation techniques, we will focus in the present project on vacancy-mediated diffusion in BCC MPEAs of the MoNbTaVW system. Owing to the high melting points of the constituent elements, BCC MPEAs were reported to possess outstanding high-temperature strength that may surpass the conventional superalloys. Indeed, the MoNbTaVW system is considered as a next-generation structural and functional alloy with superior high-temperature performance. Through the joint, interactive analyses of accurately measured and simulated tracer diffusivities for a collection of BCC MPEAs featuring different chemical complexities, e.g., random solid solutions and alloys with short-/long-range order (B2), we will not only provide an extensive set of diffusion data with unprecedented accuracy but also a thorough physical understanding of the impact of thermal vibrations, chemical interactions, element substitutions, and chemical ordering as well as their interplay. A significant advance in the fundamental understanding of diffusion and related ordering/disordering tendencies in MPEAs is expected.

由于先进的技术应用，浓缩合金，特别是所谓的多主元素合金（MPEA）中的扩散越来越受到关注，此类合金表现出独特的特征，即明显缓慢的扩散，对各种材料性能产生严重影响，例如微观结构演变、相稳定性。 MPEA 的独特特性通常源于其显着的化学复杂性，同时也给实验和理论研究带来了巨大的挑战。晶格热振动与局部环境的强烈异质性及其对 MPEA 中扩散的影响还远未被理解，这阻碍了基于斯图加特团队的共同努力对扩散率的定量，有时甚至是定性预测。 ）和明斯特（实验）都在各自的研究领域建立了领导者，并通过长期合作相互联系——本项目旨在开发准确和通用的方法来研究和从根本上理解复杂的扩散MPEA 将先进的放射性示踪剂技术与多种高精度从头计算模拟技术相结合，由于 MoNbTaVW 系统的高熔点，我们将重点研究 MoNbTaVW 系统的 BCC MPEA 中的空位介导的扩散。据报道，BCC MPEA 具有可能超越传统高温合金的出色高温强度。事实上，MoNbTaVW 系统被认为是一种优秀的高温合金。通过对一系列具有不同化学复杂性的 BCC MPEA（例如随机固溶体和具有短/长的合金）进行精确测量和模拟的示踪剂扩散率的联合交互式分析，开发出具有卓越高温性能的下一代结构和功能合金。 -范围顺序 (B2)，我们不仅将提供一组具有前所未有的准确性的广泛扩散数据，而且还将对热振动、化学相互作用、元素替代和化学排序及其影响进行彻底的物理理解预计对 MPEA 中扩散和相关有序/无序趋势的基本理解将取得重大进展。