Phase-Specific Analysis and Simulation of Micro Deformation and Damage in Metal Matrix Composites

金属基复合材料微变形和损伤的相特异性分析与模拟

• 批准号: 298892085
• 负责人: Professor Dr. Siegfried Schmauder
• 金额: --
• 依托单位: Lehrstuhl für Werkstofftechnologie (LWT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/298892085?language=en
• 关键词: Phase; Specific; Analysis; Simulation; Micro

The localization of strain and the nucleation of micro damages in ductile materials like metals are of high technical significance since these microstructural processes affect the mechanical behavior during loading, forming and machining of such materials. Moreover, there is a relationship between the regions of elevated strain on one side and the sites of micro damages and the modes of macroscopic failure on the other side. In order to control such microstructural processes, metallic materials are reinforced for example by dispersing hard particles. Such metal matrix composites (MMCs) have become more and more attractive since their mechanical properties can be tailored to various applications over a wide range.Using a combination of 2D/3D experimental analysis and simulation techniques and under consideration of residual stresses, this project aims at the understanding of micro deformation and damage processes in microstructural regions of MMCs by the example of the system Co/WC diamond:Specimens made of various Co/WC diamond MMCs will be loaded in tension to different stages of strain. In these stages, the gauge sections of the specimens are imaged by SEM and 3D micro-tomography (µCT). With a test rig which will be constructed in the project and which is dedicated for the µCT setup in situ tensile tests will be carried out. A correlation algorithm for the phase-specific analyses of the 3D strain fields will be developed and applied to the 3D images. This iterative correlation algorithm takes into account the distributions of the phases in the microstructure which can be extracted from the tomographic images. Furthermore, the effect of residual stresses, microstructural parameters and the Co/diamond bonding on the initiation of strain and stress concentration sites and the beginning of damage at a microscopic scale will be investigated.Based on the experimentally obtained phase distributions a realistic 3D FE model of the phase geometry of the Co/WC diamond MMC will be built up to simulate the micro deformation and damage processes of the investigated MMC. Displacement vector fields measured at the model boundaries will be used as boundary conditions for the FE simulation. The comparison of the simulation results with the experimental findings on the basis of strain fields, residual stresses and damage processes will help to verify the simulation model. With such a verified numerical model, it will be possible to derive a better understanding of the deformation and damage behavior of the composite by performing parameter studies concerning different phase arrangements and different phase volume fractions. The close cooperation between the experimental analyses and simulations is considered to be a key element for achieving these aims.

金属等延性材料中应变的局部化和微损伤的成核具有很高的技术意义，因为这些微观结构过程会影响此类材料在加载、成型和加工过程中的机械行为。此外，一侧的高应变区域与另一侧的微观损伤部位和宏观失效模式之间存在关系。为了控制这种微观结构过程，例如通过分散硬质颗粒来增强金属材料。这种金属基复合材料（MMC）变得越来越有吸引力，因为它们的机械性能可以根据各种应用进行定制。该项目结合2D/3D实验分析和模拟技术，在考虑残余应力的情况下，旨在以Co/WC金刚石系统为例，了解MMC微观结构区域的微变形和损伤过程：由各种材料制成的样品 Co/WC 金刚石 MMC 将承受不同应变阶段的张力。在这些阶段中，通过 SEM 和 3D 显微断层扫描 (μCT) 对样本的规格部分进行成像。项目中将建造专用于 µCT 装置的试验台，进行原位拉伸试验。将开发用于 3D 应变场特定相分析的相关算法并将其应用于 3D 图像。这种迭代相关算法考虑了可以从断层扫描图像中提取的微观结构中的相分布。此外，还将研究残余应力、微观结构参数和 Co/金刚石键合对微观尺度上应变和应力集中位置的萌生以及损伤开始的影响。基于实验获得的相分布，将建立 Co/WC 金刚石 MMC 相几何形状的真实 3D 有限元模型，以模拟所研究的 MMC 的微变形和损伤过程。在模型边界测量的位移矢量场将用作有限元模拟的边界条件。将模拟结果与基于应变场、残余应力和损伤过程的实验结果进行比较将有助于验证模拟模型。有了这样一个经过验证的数值模型，通过进行有关不同相排列和不同相体积分数的参数研究，将有可能更好地理解复合材料的变形和损伤行为。实验分析和模拟之间的密切合作被认为是实现这些目标的关键要素。