Reinforcement and damage mechanisms in three- and four-phase aluminum-matrix composites

点击翻译按钮获取中文摘要

We will use synchrotron computed tomography and scanning electron microscopy to study the microstructural changes of three- and four-phase composites with Al-Mg-Si-alloy matrix, both after heat treatment and plastic pre-strain. It has been observed that the precipitated Si phase spherodises after heat treatment. Here we will investigate which consequence has this microstructure development on the mechanical properties of the composites. We will also investigate how the ceramic reinforcement (SiC particles and Al2O3 fibres) fails, and which consequences this failure has on the whole composite damage behavior.To the latter aim, in-situ neutron diffraction uniaxial compression and tension experiments will be carried out to disclose the load transfer between the various phases. Those experiments are supposed to directly show the effect of the microstructural changes on the mechanical properties of the composites. We will also determine phase specific residual stresses in the various composites.All experimental results will be input into a model capable of predicting phase specific stress also in amorphous phases (not detectable by neutron diffraction). The model will take into account realistic microstructures and residual stress, and will be used to predict the materials behavior under cyclic loading.