On the Use of Microstructure Characteristics to Predict Metal Matrix Composites’ Macroscopic Mechanical Behavior

Abstract

In recent decades, the construction of statistically similar representative volume elements (SSRVEs) of materials for use in numerical analyses has been accomplished utilizing various methods, tools, and frameworks. Such a framework is introduced in this work, where the creation of 3D SSRVEs of metal matrix composites was investigated to assess their mechanical properties with reference to the material’s microstructure. The material studied was a composite based on AA7075 alloy reinforced with carbon fibers, with volume fractions of 0%, 4%, 8%, and 12%. The statistics of the alloy’s microstructure were extracted by segmenting an SEM image and fitting the precipitate particles’ sizes with respect to a lognormal distribution. The open-source software DREAM.3D was used to construct 3D ensembles and the Abaqus FEA software was employed for the mechanical testing simulations. By plotting the tensile stress–strain curves for the composites, it was found that the elastic modulus increased with the fibers’ volume fraction, obeying the rule of mixtures for discontinuous fibrous composites. The fiber efficiency factors were also calculated. The yield stresses of the composites were found and compared to the ones expected according to the shear-lag model, indicating major differences.