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

关于近表面残余应力和结构梯度的分析，能量色散（艾德）衍射最近已成为一个有趣的替代成熟的角度色散（AD）衍射方法。艾德法最重要的优点是在固定但可任意选择的测量方向上提供完整的衍射图样，这些图样不仅包含材料的成分、相特异性残余应力、晶体学织构和微观结构的完整信息，而且还包含这些性质的深度分布信息，可进一步传播和开辟新的应用领域，这将对应于艾德方法的高潜力，目前受到专用于能量色散衍射的同步加速器光束线的受限访问的限制。在本研究项目的范围内，计划将艾德方法从同步加速器转移到实验室尺度。其目的是为测量和评估策略创建科学基础，该策略适用于实验室条件，其特点是光子通量低得多，光束发散度大。新方法的可能性和局限性将通过明确定义的材料条件进行研究，因此，该项目的主要目标是利用艾德衍射提供的功能，以获得尽可能多的近表面材料属性的信息，同时保持时间和仪器的支出尽可能少。

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.