Experimental analysis of the orientation dependence of deformation laminates.

该项目的目的是对金属中晶体取向的局部变形诱导图案进行实验研究，并将观察到的微观结构与理论模型进行定量比较。在上一个资助期内，我们在结合层压理论和实验方面取得了重大进展。我们将取向显微镜EBSD（电子背散射衍射）在剪切变形铜单晶中观察到的取向图案与运动学兼容层压板模型（使用本研究计划中开发的技术）进行了定量相关。实验观察到的图案化现象的规格作为一个层压体的形成，其被预测为基于强大的潜在硬化是新的显微镜和微塑性的研究领域。然而，“能源景观”提供的模式，充满活力的有利层压变化尚未探讨。因此，在申请资助期间，我们建议对图案化现象的取向相空间进行实验研究，并得到层压模型（P6，Dondl/Müuller）相关性的支持。本文将对铜单晶和B_2有序NiAl单晶进行无摩擦均匀加载的剪切实验。这两种材料将在几个方向上塑性变形，以便可以研究单，双和三重滑动活动。在B2有序NiAl的情况下，少量的潜在滑移系统允许滑移系统的精确激活，并且应该导致更明显的取向图案化。此外，将与P6合作研究弯曲实验中提供的自由表面边界条件的最佳微观结构。动态过程的研究，如初始步骤的层压和随后的微观结构演变是在微塑性特别感兴趣的。为了研究微观结构动力学，我们将对层压微观结构的演变进行实验，这将伴随着时间连续的有限晶体塑性计算（P3，Hackl/Kochmann/瓦格纳）。探讨了层合板形成的能量原因和引发和演化的机制。此外，将进行关于二阶层合板的形成和演化以及这些结构的晶体学分析的实验。进一步发展高阶层合板（P3）的有限塑性模型将支持这一研究。除了研究层压过程外，我们还将研究层压显微结构中位错结构的演化。这些调查提供了深入的位错捕获和位错墙的产生与层压形成的机制。为此，我们将应用电子沟道对比技术，该技术允许通过使用EBSD来观察位错结构并同时分析周围的微观结构。从而探讨位错重排对层状组织形成的影响.这样，我们就可以回答存在于层压理论中的一个悬而未决的问题，例如细胞结构是否可以被理解为单滑移区域的相容排列。

The aim of the project is the experimental investigation of the local deformation-induced patterning of the crystallographic orientation in metals and the quantitative comparison of the observed microstructures with theoretical models. In the previous funding period, we made significant progress in uniting lamination theory and experiments. We quanti- tatively correlated the orientation patterning observed in shear deformed copper single crystals using orientation microscopy EBSD (electron back scatter diffraction) with a model of kinematically compatible laminates using a technique developed within this re- search initiative. The specification of the experimentally observed patterning phenomenon as a laminate the formation of which is predicted to be based on strong latent hardening is novel in the research fields of microscopy and microplasticity. However, the ”energy landscape” provided by the model for energetic favorable laminate variations is not yet explored. Therefore, for the applied funding period, we propose the experimental in- vestigation of the orientation phase space of patterning phenomena supported by the correlation to the lamination model (P6, Dondl/M¨uller). Shear experiments for well con- trolled frictionless homogeneous loading will be performed on single crystals of copper and B2 ordered NiAl. Both materials will be plastically deformed in several orientations so that single, double, and triple slip activity can be studied. A small number of poten- tial slip systems in case of B2 ordered NiAl allows precise activation of the slip systems and should lead to more pronounced orientation patterning. Furthermore, study on opti- mal microstructures to free surface boundary conditions provided in bending experiments will be performed in cooperation with P6. Study of the dynamic processes such as the initial steps of lamination and subsequent microstructure evolution are of particular in- terest within the microplasticity. To study the microstructure dynamics, we will perform experiments on the evolution of laminated microstructures which will be accompanied by time-continuous finite crystal plasticity calculations (P3, Hackl/Kochmann/Wagner). The energetic reasons and the mechanisms for the initiation and evolution of the laminate formation will be explored. Moreover, experiments regarding formation and evolution of rank-two laminates and crystallographic analysis of these structures will be performed. This investigations will be supported by further development of the finite plasticity model for high-order laminates (P3). Beside the study of the progress of the lamination, we will investigate the evolution of the dislocation structures within the laminated microstruc- ture. These investigations provide insights into the mechanisms of dislocation trapping and generation of dislocation walls in correlation with the laminate formation. For this reason, we will apply the electron channeling contrasts technique which allows the ob- servation of the dislocation structures and the simultaneous analysis of the surrounding microstructure by using EBSD. Thus, we can explore the impact of the dislocation rear- rangements on the formation of laminated microstructure. This way, we can answer one of the open questions existing in lamination theory, such as whether cell structures may be understood as compatible arrangements of regions of single slip.