Relationship between both thickness and degree of crystallisation of BN interphases and the mechanical behaviour of SiC/SiC composites

SiC/BN/SiC-Si single-ply composites with Hi-Nicalon S™ fibres were synthesised by chemical vapour infiltration followed the liquid route. These are model representing behaviour of industrial intended to be used as structural parts in hot sections aeronautical engines. Four interphases two different degrees crystallisation and, each case, thicknesses tested. The interfacial shear stress measured fibre push-out test is significantly higher when degree BN interphase low. Yet, this it decreases thickness interphase. This bonding also associated, albeit less significantly, better macro-mechanical properties tensile and tests. cracks observed composite microscopy techniques long open. Depending on interphases, debonds more or pronounced occur preferentially at locations system.