Modelling of the interfacial behaviour in the Hi-Nicalon fibre-reinforced α-Si3N4 ceramic matrix composites using microindentation tests

Microindentation tests have been performed on a Hi-Nicalon fibre-reinforced α-silicon nitride ceramic matrix composite. The effects of the variation of the maximum applied load on the interfacial properties have been investigated. The frictional stress, plotted as a function of the fibre radius for three different maximum applied stress values, shows evidence of Poissonʹs effect. A model describing the stress transfer is proposed, assuming that the frictional stress is entirely Coulombian and taking into account the contribution of the fibre roughness, the residual stress and the fibre expansion due to Poissonʹs effect. Thereby, it was possible to simulate the load–fiber displacement relationships and to derive frictional stress values adjusted for Poissonʹs effect.