In-situ studies of strain accommodation in MAX phase materials for advanced nuclear energy

先进核能 MAX 相材料应变调节的原位研究

• 批准号: 2282516
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2282516
• 关键词: situ; studies; strain; accommodation; MAX

MAX phases are 2D-layered hexagonal carbides or nitrides that can exhibit very high mechanical damage tolerance at high temperatures. In common with ceramics, they are significantly less activated than metals by fast neutron irradiation. Hence they have potential applications in structural applications for advanced nuclear fission. However, the structure/property relationships and mechanisms of damage accumulation in MAX phases need to be better understood for microstructure-based modelling to support the design and development of materials and engineering components. Strain mapping by both image analysis and diffraction has revolutionized studies of deformation in structural materials. Together, they can provide excellent knowledge of both the elastic and plastic strain states within complex structures, which are internally "strain gauged" in three-dimensions with high spatial resolution. Image correlation tools applied to tomographs can measure three-dimensional deformation and total strain states with high precision. Diffraction analysis to measure elastic strains within bulk materials is also routine with neutrons and also on high energy synchrotron X-ray beam-lines. The project aims to use X-ray and neutron diffraction and imaging to map, in situ and in 3D, both the total and elastic strains under load and at elevated temperature, and thereby perform novel studies of the mechanisms of strain accommodation in bulk MAX phase materials for nuclear energy, with emphasis on the effects of strain history, microstructure texture and material heterogeneity, in order to improve material reliability and performance. The objectives of the project are to study, in particular, the differences between phase pure and commercial purity MAX phase materials from the TiAlC system, including the application of high resolution electron backscatter diffraction (EBSD) to study the transfer of strain between grains and phases, which may be affected by the texture that is introduced during processing. This project interacts closely with a parallel project, starting at the same time, that is conducting studies of strain accommodation in MAX phase materials for advanced nuclear energy at the microscale, using high temperature nano-indentation and high resolution microscopy. This project collaborates with SCK-CEN (Belgium) who are developing MAX phases for nuclear applications in conjunction with the European Energy Research Alliance Joint Programme in Nuclear Materials that aims to develop materials for next generation sustainable nuclear energy. The project also connects with the H2020 Il Trovatore programme on Innovative cladding materials for advanced accident-tolerant energy systems, in which standard mechanical testing (including studies of irradiated materials) are being conducted by SCK-CEN, together with electron-microscopy microstructure characterisation by EBSD and Transmission electron microscopy. This project falls within the EPSRC Energy Research Theme (Nuclear Power).

MAX相是二维层状六方碳化物或氮化物，在高温下可表现出非常高的机械损伤容限。与陶瓷一样，它们在快中子辐照下的活性明显低于金属。因此，它们在先进核裂变的结构应用中具有潜在的应用。然而，在MAX阶段的结构/性能关系和损伤累积的机制需要更好地理解的微观结构为基础的建模，以支持材料和工程部件的设计和开发。通过图像分析和衍射的应变映射已经彻底改变了结构材料变形的研究。总之，它们可以提供复杂结构中弹性和塑性应变状态的出色知识，这些结构在三维空间中以高空间分辨率进行内部“应变测量”。应用于断层摄影机的图像相关工具可以高精度地测量三维变形和总应变状态。测量散装材料内弹性应变的衍射分析也是中子和高能同步加速器X射线束线的常规方法。 该项目旨在利用X射线和中子衍射和成像技术，在现场和三维绘制载荷和高温下的总应变和弹性应变，从而对核能用MAX相材料的应变调节机制进行新的研究，重点是应变历史、微观结构和材料异质性的影响，以提高材料的可靠性和性能。该项目的目标是研究，特别是，从TiAlC系统的相位纯和商业纯度MAX相材料之间的差异，包括高分辨率电子背散射衍射（EBSD）的应用，以研究晶粒和相位之间的应变传递，这可能会受到在加工过程中引入的纹理的影响。该项目与同时开始的一个平行项目密切互动，该项目正在利用高温纳米压痕和高分辨率显微镜研究微尺度先进核能MAX相材料的应变调节。该项目与SCK-CEN（比利时）合作，后者正在与欧洲能源研究联盟核材料联合计划合作开发用于核应用的MAX阶段，该计划旨在开发下一代可持续核能的材料。该项目还与H2020 Il Trovatore计划有关先进事故容限能源系统的创新包覆材料，其中标准机械测试（包括辐照材料的研究）由SCK-CEN进行，以及EBSD和透射电子显微镜的电子显微镜微观结构表征。该项目福尔斯属于EPSRC能源研究主题（核能）。