Multiscale characterisation of creep deformation of materials for fusion reactors

核聚变材料的技术成熟度低，新颖且只能小批量生产。因此，有必要从给定数量的材料中提取尽可能多的信息。该项目的目的是为了研究材料在蠕变状态下的性能，主要使用91级钢作为EUROFER 97的模型材料。这项工作将利用图像处理技术数字图像相关（DIC）的固有可扩展性，利用可见光和扫描电子显微镜（SEM）的电子成像相结合，在同一样品上同时量化多个长度尺度上的蠕变变形。与单轴测试相比，宏观尺度DIC将有助于设计样品以体验空间应力梯度，减少表征蠕变行为所需的材料量。显微结构尺度DIC将用于观察样品所经历的应力状态范围内的晶粒现象。这种测试尺度的组合将使宏观尺度的行为可以用晶粒尺度的行为来解释，从而对材料的蠕变机制和破坏模式有更细致的了解。

Materials for fusion are low technology readiness level, novel and only available in small volumes. Therefore, there is a need to extract as much information from a given amount of material as possible. The aim of this project is to work towards doing just that for material behaviour in the creep regime, primarily using Grade 91 steel as a model material for EUROFER 97. This work will utilise the inherent scalability of the image processing technique Digital Image Correlation (DIC) to quantify creep deformation at multiple length scales concurrently on the same sample, using a combination of visible light and electron imaging using a scanning electron microscope (SEM). The macroscale DIC will facilitate the sample to be designed to experience a spatial stress gradient, reducing the amount of material required to characterise creep behaviour when compared to uniaxial testing. The microstructural scale DIC will be used to observe grain scale phenomena across the range of stress states experienced by the sample. This combination of test scales will enable macroscale behaviour to be explained by grain-scale behaviour, developing a more nuanced insight into the material's creep mechanisms and failure modes.