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.

在金属等延性材料中，应变的局部化和微损伤的形核具有很高的技术意义，因为这些微观组织过程会影响这些材料在加载、成形和加工过程中的力学行为。此外，一侧的应变升高区域与另一侧的微观损伤部位和宏观破坏模式之间存在一定的关系。为了控制这种微观结构过程，金属材料被增强，例如通过分散硬颗粒。这种金属基复合材料（MMCs）由于其机械性能可以在广泛的范围内适应各种应用而变得越来越有吸引力。本项目采用二维/三维相结合的实验分析和模拟技术，在考虑残余应力的情况下，以Co/WC金刚石为例，了解mmc微结构区域的微观变形和损伤过程：将各种Co/WC金刚石mmc制成的试样在拉伸载荷下加载到不同的应变阶段。在这些阶段，通过SEM和3D微断层扫描（µCT）对试件的规范截面进行成像。将在项目中建造一个试验台，该试验台专门用于微CT设置，将进行现场拉伸测试。本文将开发一种用于三维应变场相位分析的相关算法，并将其应用于三维图像。该迭代相关算法考虑了从层析图像中提取的微观结构中相的分布。此外，还将在微观尺度上研究残余应力、微观结构参数和Co/金刚石结合对应变和应力集中点的起始以及损伤开始的影响。基于实验得到的相分布，建立了Co/WC金刚石复合材料相几何的三维有限元模型，模拟了复合材料的微观变形和损伤过程。在模型边界处测量的位移矢量场将作为有限元模拟的边界条件。基于应变场、残余应力和损伤过程的仿真结果与实验结果进行比较，有助于验证仿真模型。有了这样一个经过验证的数值模型，通过对不同相排列和不同相体积分数进行参数研究，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因素。