Indentation behavior of heterogeneous materials

摘要

A combined computational and experimental study was undertaken to investigate the effect of microstructural heterogeneity on indentation response. Finite element analyses were carried out to simulate the stress-strain and indentation behavior of a model heterogeneous system consisting of hard particles embedded within a ductile matrix. The indentation response consistently overestimates the overall strength of the composite. Experiments on particle-reinforced metal matrix composites confirmed the non-correspondence between the indentation and stress-strain responses, even when the indent size is much greater than the microstructural feature size. A quantitative microscopic characterization was employed to show the local increase in particle concentration directly underneath the indentation, which is largely responsible for the overestimation of material strength by indentation.