Energy-dispersive analysis of near surface residual stress and microstructure gradients by means of conventional laboratory X-ray sources

对于近表面残余应力和结构梯度的分析，能量色散衍射（ED）是近年来替代角色散衍射（AD）方法的一种有趣的方法。电子衍射法最重要的优点是，它提供了在固定但任意选择的测量方向上的完整衍射图，不仅包含了材料的成分、相特定残余应力、晶体织构和微观结构的完整信息，而且还包含了这些性质的深度分布。进一步的传播和开辟新的应用领域，这将与ED方法的高潜力相对应，目前受到限制访问专用于能量色散衍射的同步加速器光束线。在这个研究项目的范围内，计划将ED方法从同步加速器转移到实验室尺寸。目的是为测量和评估策略创造科学基础，该策略适应于以低得多的光子通量和大光束散度为特征的实验室条件。新方法的可能性和局限性将通过定义良好的材料条件进行研究。因此，该项目的主要目标是利用ED衍射提供的特征，以获得尽可能多的近表面材料特性信息，同时尽可能减少时间和仪器的花费。

Concerning the analysis of near surface residual stress and structural gradients, energy-dispersive (ED) diffraction recently has become an interesting alternative to the well established angle-dispersive (AD) diffraction methods. The most important advantage of the ED method is that it provides complete diffraction patterns in fixed but arbitrarily selectable measuring directions which do not only contain integral information on composition, phase specific residual stresses, crystallographic texture and microstructure of the material, but also on the depth distribution of these properties.Further dissemination and opening up new fields of application, which would correspond to the high potential of the ED method are currently limited by the restricted access to synchrotron beamlines that are dedicated to energy-dispersive diffraction. Within the scope of this research project it is planned to transfer the ED method from synchrotron to laboratory dimensions. The objective is to create a scientific basis for a measuring and evaluation strategy which is adapted to the lab conditions being distinguished by a much lower photon flux and a larger beam divergence. The possibilities and limitations of the new approach are to be investigated by means of well-defined material conditions.Therefore, the main goal of the project is to exploit the features provided by ED diffraction in order to gain as much as possible information on the near surface material properties while simultaneously keeping the expenditure of time and instrumentation as small as possible.