Abstract
Microindentation tests (spherical indentation) have been used to evaluate local mechanical properties of Hi-Nicalon fibre reinforced silicon nitride ceramic matrix composite. This technique gave a satisfactory estimate of in-situ longitudinal Young’s modulus of both the matrix and the fibres which correlates quite well with 3-points bend tests. By means of the same technique, but with a different indenter (pyramidal), the interfacial behaviour has been studied. When varying the maximum applied load, Fmax, and considering a constant interfacial shear stress, the presence of Poisson’s effect has been detected. Based on Coulomb’s law of friction, a model has been proposed to extract frictional stress values adjusted for Poisson’s effect. The advantages of this model are the explicit integration of all contributions to the clamping stress at the fibre-matrix interface as well as the use of measured topography properties of Hi-Nicalon fibres.
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