TP2: Thermomechanical characterization and microstructural analysis of the interaction of shear bands with elements of the microstructure

绝热剪切带的形成是金属材料在高变形速率下的变形过程。剪切带形成的特点是塑性变形过程中的能量耗散，这与局部温度升高有关，导致局部软化，最终导致后续变形的日益明显的局部化。从材料科学的角度来看，对剪切带形成的详细了解是有趣的，从实验上具有挑战性，从技术的角度来看也是高度相关的，特别是在高速下料的背景下。本研究项目的一个主要目标是研究不同初始组织对非合金钢和低合金钢以及非时效硬化铝合金中不同类型剪切带形成和生长的影响。此外，该项目旨在制定评估高速下料过程中所研究材料剪切倾向的标准，特别关注材料的应变率敏感性、强度和导热性。特别是，目的是了解初始微观结构和由此产生的剪切带性能之间的关系。研究的重点不仅是宏观力学行为的研究，还包括剪切带的微观结构和微观力学特征，并考虑不同应力状态的影响。此外，高速下料产生的切削表面将被系统地表征，并确定裁剪明确的表面特性的条件。因此，通过对相关微观结构机制的清晰理解，将对研究单位的中心研究目标做出重大贡献-从绝热剪切带的开始，通过其生长和与微观结构特征的相互作用，到高速下料过程中产生的功能表面。

Adiabatic shear band formation occurs as a deformation process in metallic materials particularly at high deformation rates. Shear band formation is characterized by energy dissipation during plastic deformation, which is associated with a local temperature increase that leads to local softening and, finally, to an increasingly pronounced localization of the subsequent deformation. A detailed understanding of shear band formation is interesting from the point of view of materials science, experimentally challenging and also highly relevant from a technological point of view, especially in the context of high-speed blanking. A key objective of this research project is to investigate the influence of different initial microstructures on the formation and growth of different types of shear bands in unalloyed and low-alloyed steels, respectively, as well as in a non age-hardenable aluminum alloy. The project furthermore aims at developing criteria for the evaluation of the shear tendency of the investigated materials during high-speed blanking, with a special focus on strain rate sensitivity, strength and thermal conductivity of the materials. In particular, the aim is to understand the relationships between the initial microstructures and the resulting shear band properties. The focus is not only on the macroscopic investigation of the mechanical behavior but also on the microstructural and micromechanical characterization of shear bands, with additional consideration of the influence of different stress states. Moreover, the cutting surfaces produced by high-speed blanking will be systematically characterized, and conditions for tailoring well-defined surface properties will be identified. Consequently, a significant contribution will be made to the central research goals of the Research Unit by the development of a clear understanding of the relevant microstructural mechanisms – from the initiation of an adiabatic shear band, via its growth and interaction with microstructural features, to the functional surface generated during high-speed blanking.