Novel analytical methods for assessing local environments in multicomponent systems for nuclear applications

用于评估核应用多组分系统局部环境的新颖分析方法

• 批准号: 2890744
• 金额: --
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2890744
• 关键词: Novel; analytical; methods; assessing; local

High entropy alloys, a relatively new class of materials, represent a novel alloy design strategy based on combining multiple elements in near-equiatomic proportions. The field is based on four core principles, many of which directly relate to atomic scale structural effects within the system, such as local atomic displacements and configurational environments. These materials are being investigated for a number of possible applications. One potential beneficial property demonstrated by some high- and medium-entropy alloys is radiation damage tolerance for nuclear applications, which it has been suggested relates to the local environment. Answering questions about the local atomic environment in these materials is essential if they are to be tuned for purpose.Total scattering, a type of diffraction method based on examining the pattern produced by X-rays/Neutrons scattered from a sample, provides a probe of the local atomic environment in material systems. The development of large box modelling methods, Reverse Monte Carlo, has already provided useful insights in a host of complex chemical systems, functional oxides and metal organic frameworks [1] from total scattering data. Recently, the application of the technique has been demonstrated for exploring local effects, such as short-range order, in simple binary metallic systems [2,3]. However, the complexity of the system that can be probed using this method is currently unknown.This PhD project will look at development of methodologies for the analysis of multi-component systems using total scattering. We will begin with simple case example materials, building in complexity to more involved systems of industrial interest. This will involve, metallurgical sample preparation including powder manufacturing methods, and characterisation of the samples by scanning and transmission electron microscopy. Total scattering data will be acquired at the ISIS Neutron Source and Diamond Light Source, involving close collaboration with scientists at UK national research facilities. Analysis of these data will be carried out using RMCProfile and PDFGui, as well as developing bespoke analysis code. Concurrent with these studies, computational simulation will be used to assess theoretical analytical limits of the technique.

高熵合金是一类相对较新的材料，代表了一种基于以近等原子比例组合多种元素的新型合金设计策略。该领域基于四个核心原则，其中许多原则与系统内的原子尺度结构效应直接相关，例如局部原子位移和构型环境。正在研究这些材料的多种可能的应用。一些高熵和中熵合金表现出的一种潜在有益特性是核应用的辐射损伤耐受性，有人认为这与当地环境有关。如果要针对目的进行调整，回答有关这些材料中局部原子环境的问题至关重要。全散射是一种基于检查从样品中散射的 X 射线/中子产生的图案的衍射方法，提供了一种探针材料系统中的局部原子环境。大盒建模方法（逆蒙特卡罗）的发展已经为许多复杂化学系统、功能氧化物和金属有机框架[1]的总散射数据提供了有用的见解。最近，该技术的应用已被证明可用于探索简单二元金属系统中的局部效应，例如短程有序[2,3]。然而，使用这种方法探测的系统的复杂性目前尚不清楚。该博士项目将着眼于开发使用全散射分析多组分系统的方法。我们将从简单的案例示例材料开始，逐步构建复杂的工业利益相关系统。这将涉及冶金样品制备，包括粉末制造方法，以及通过扫描和透射电子显微镜表征样品。总散射数据将在 ISIS 中子源和钻石光源处获取，涉及与英国国家研究机构的科学家的密切合作。这些数据的分析将使用 RMCProfile 和 PDFGui 进行，并开发定制的分析代码。在这些研究的同时，计算模拟将用于评估该技术的理论分析极限。