Experimental analysis of the orientation dependence of deformation laminates.

变形层合体方向依赖性的实验分析。

• 批准号: 35757377
• 负责人: Professor Dr.-Ing. Dierk Raabe
• 金额: --
• 依托单位: Max-Planck-Institut für Eisenforschung GmbH (MPIE)
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/35757377?language=en
• 关键词: Experimental; analysis; orientation; dependence; deformation

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.

该项目的目的是实验研究局部变形诱导的金属晶体取向模式，并将观察到的微观结构与理论模型进行定量比较。在之前的资助期内，我们在层压理论和实验的结合方面取得了重大进展。我们使用取向显微镜（EBSD）（电子反向散射衍射）定量地将剪切变形铜单晶中观察到的取向图案与使用本研究计划中开发的技术的运动学相容层压板模型相关联。在显微学和微塑性研究领域，将实验观察到的图案现象描述为层压，并预测其形成是基于强潜硬化。然而，该模型所提供的能量有利层压板变化的“能量景观”尚未得到探索。因此，在申请资助期间，我们建议通过与层压模型的相关性来支持图案现象的取向相空间的实验研究（P6, Dondl/M¨uller）。对铜单晶和B2有序NiAl单晶进行了可控无摩擦均匀加载剪切实验。这两种材料都将在几个方向上发生塑性变形，以便研究单滑移、双滑移和三滑移活动。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，并应导致更明显的定向模式。此外，将与P6合作进行弯曲实验中提供的自由表面边界条件下的最佳微观结构研究。动态过程的研究，如层合的初始步骤和随后的微观结构演变是微塑性研究中特别感兴趣的。为了研究微观结构动力学，我们将对层状微观结构的演变进行实验，并伴随时间连续的有限晶体塑性计算（P3, Hackl/Kochmann/Wagner）。本文将探讨层状地层形成和演化的能量原因和机制。此外，还将进行有关二级层压板的形成和演化的实验以及这些结构的晶体学分析。高阶层压板（P3）有限塑性模型的进一步发展将支持这一研究。除了研究叠层的进展外，我们还将研究叠层微观结构中位错结构的演变。这些研究提供了与叠层形成相关的位错捕获和位错壁生成机制的见解。因此，我们将采用电子通道对比技术，该技术可以观察位错结构，并通过EBSD同时分析周围的微观结构。因此，我们可以探讨位错后场对层状组织形成的影响。这样，我们就可以回答层压理论中存在的一个悬而未决的问题，例如细胞结构是否可以理解为单滑移区域的相容排列。