Full elastic strain tensor mapping of polycrystalline Cr coated Zr nuclear claddings with high resolution Diffraction Microstructure Imaging

In order to enhance the oxidation resistance of nuclear Zr based fuel cladding tubes, PVD Cr coatings are one of the most advanced concepts. These coatings exhibit complex interactions at the interface between Cr and the Zr substrate, mostly driven by the micro-mechanical state. In this context, being able to access non-destructively to the local strain field is of prime interest. Following previous micro-diffraction Laue and DAXM mappings on an as-deposited microstructure, we need to further refine the knowledge of the mechanical state with a multimodal approach. In this scope, scanning-3DXRD and DFXM imaging techniques would allow to derive full elastic strain tensor maps, respectively over large representative slices through the interface, and on finer 3D maps of individual Zr grains – in both cases with optimal resolution (10-1 µm spatially and 10-5 in strain). The resulting dataset will also provide an opportunity to compare the performances of each technique.

为提升核级锆基燃料包壳管的抗氧化性能，物理气相沉积（PVD）铬涂层是当前最先进的技术方案之一。此类涂层在铬与锆基体的界面处存在复杂相互作用，该相互作用主要由微观力学状态主导。在此背景下，实现对局部应变场的无损检测具有极高的研究价值。基于此前针对沉积态微观组织开展的微衍射劳厄（Laue）与DAXM成像测绘研究，本研究需通过多模态方法进一步细化对力学状态的认知。在此研究框架下，扫描三维X射线衍射（scanning-3DXRD）与DFXM成像技术可分别获取界面处大尺寸代表性切片的完整弹性应变张量图谱，以及单个锆晶粒的高分辨率三维应变图谱；两类技术均具备最优分辨率：空间分辨率可达0.1 µm，应变分辨率可达10⁻⁵。本数据集还将为对比各技术的性能提供研究契机。