Understanding lattice strain distributions within anisotropic FCC and HCP polycrystals – key for materials design and modelling

The relationship between macroscopic and microscopic stresses is central for a quantitative understanding of the mechanical behaviour of structural materials. The goal of this proposal is the validation and improvement of micromechanical methods to estimate local stresses for anisotropic FCC and HCP polycrystalline materials. A particular focus lies on the Maximum-Entropy method (MEM) which is capable of predicting local stresses based on macroscopic mechanical properties and microstructural information. We propose to implement Diffraction Contrast Tomography (DCT) to determine the shape, arrangement, orientation and average elastic strain tensor of a representative ensemble of individual grains within a polycrystal for increasing tensile loading. Based on this unique experimental dataset, simulations and analytical methods can be combined to validate the MEM, yielding a new computationally extremely efficient approach for hierarchical materials informatics.

宏观与微观应力之间的关系是定量理解结构材料力学行为的核心。本研究计划旨在验证并改进用于估算各向异性面心立方（FCC）和六方最密堆积（HCP）多晶材料局部应力的微观力学方法。研究特别聚焦于最大熵方法（MEM），该方法可基于宏观力学性能与微观结构信息预测局部应力。我们计划采用衍射衬度断层扫描（DCT）技术，测定多晶材料中具有代表性的单个晶粒集合在递增拉伸载荷下的形状、排列、取向及平均弹性应变张量。基于这一独特的实验数据集，可结合模拟与分析方法验证MEM，从而为分层材料信息学提供一种计算效率极高的新方法。