Quantitative analysis of local deformation and direct correlation with microstructural and mechanical parameters during equal channel angular pressing in tools with variable geometries

可变几何形状工具等通道角冲压过程中局部变形的定量分析以及与微观结构和机械参数的直接相关性

• 批准号: 465563128
• 负责人: Professor Dr.-Ing. Martin Franz-Xaver Wagner
• 金额: --
• 依托单位: Professur Werkstoffwissenschaft
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465563128?language=en
• 关键词: Quantitative; analysis; local; deformation; direct

Equal Channel Angular Pressing (ECAP) is a processing technique that allows to subject metallic materials to severe plastic deformation which leads to massive grain refinement. The resulting ultrafine-grained materials are characterized by exceptional mechanical properties (high strength in combination with good ductility), making them potentially attractive for applications in, for instance, light-weight design. While the effect of ECAP on microstructure and properties of many alloys has been studied in great detail in recent years, there still exists a fundamental knowledge gap with respect to local deformation in the plastic deformation region of different ECAP tools: typically, equivalent strains are only estimated based on simplified models that do not consider, for example, the experimentally documented effects of material hardening or of a commonly applied back-pressure. A more detailed understanding of local (plastic) deformation, however, is needed in order to quantitatively describe the interrelationships between microstructural deformation mechanisms and grain refinement, which have only been analyzed qualitatively so far, and to fundamentally study and predict physical metallurgy processes as a function of material and processing parameters. The principal investigator has recently extended an analytical model that accurately describes the local deformation in 90°-ECAP tools along flow lines such that it can be also used to analyze arbitrary tool geometries. In combination with a high-resolution visioplastic technique, also developed in preliminary work, there now exists a tool-set that allows to study the key hypothesis of this proposal – the assumption that the actual equivalent strain (as expressed by the flow line exponent, its gradient in the work-piece, and the evolution of these parameters with increasing number of ECAP passes) represents a physically relevant measure that can be corelated with (or even used to quantitatively predict) many different phenomena, like microstructural and texture evolution, material properties, or damage accumulation. In this project, three model alloys and four different ECAP tools will be used to experimentally characterize the plastic deformation region under different processing conditions and how plastic deformation proceeds along different flow lines. Image recognition algorithms, based on artificial intelligence, will be developed and used to accurately fit local deformation on three complementary levels. This will for the first time also allow to evaluate the quality of different flow line models and thus to provide a benchmark test for different modeling approaches that are currently established in the ECAP community. Finally, the experimental and theoretical work will also provide the means to clearly identify relevant processing and material parameters, and to directly relate them with the resulting macroscopic properties.

相等的通道角压力（ECAP）是一种处理技术，它允许将金属材料对严重的塑性变形，从而导致大量的晶粒细化。所得的超铁粒材料的特征是具有特殊的机械性能（高强度与良好的延展性结合使用），从而使它们具有在诸如轻质设计的应用中具有吸引力。虽然ECAP对许多合金具有的微观结构和特性的影响近年来已经进行了详细研究，但仍然存在有关不同ECAP工具的塑性变形区域中局部变形区域的基本知识鸿沟：通常，等效菌株仅基于简化模型来估计，例如，不考虑实验性的效果或实验性效应。然而，需要对局部（塑性）变形进行更详细的了解，以定量地描述微观结构变形机制和谷物细化之间的相互关系，到目前为止，这些相互关系仅在定性上进行了定性分析，并从根本上研究和预测物理冶金过程作为材料和处理参数的功能。主要研究者最近扩展了一个分析模型，该模型可以准确地描述沿流线的90°ECAP工具中的局部变形，以便也可以用于分析任意工具几何形状。现在存在于初步工作中开发的高分辨率视觉塑性技术的结合，现在存在一个工具集，可以研究该提案的关键假设，即假设的假设是，实际等效应变的假设（如流量线指数所表达（由流动线指数表达）（由工作人员中的梯度梯度表达，以及与这些参数相关的ecap ecap passeants的进化），也可以衡量的ecap ecaps ecaps ecaps的进化）定量预测）许多不同的现象，例如微结构和纹理演化，材料特性或损害准确性。在该项目中，将使用三种模型合金和四种不同的ECAP工具在不同的处理条件下实验表征塑料变形区域以及塑性变形如何沿不同流动线进行。基于人工智能的图像识别算法将被开发并使用，以准确拟合三个完整级别的局部变形。这将首次允许评估不同流线模型的质量，从而为当前在ECAP社区中建立的不同建模方法提供基准测试。最后，实验和理论工作还将提供清楚地识别相关处理和材料参数的手段，并将它们与所得的宏观特性直接相关。