Polycrystalline alumina matrix uniaxially reinforced with monocrystalline alumina fiber (sapphire) composites were fabricated following two different processing routes: hot pressing (HP) and hot isostatic pressing (HIP). A porous zirconia coating was included at the fiber/matrix interface of both types of composite. A microindentation technique (push-out) was used to assess the interfacial properties of the two, and this revealed differences in their push-out behavior as observed in the load-deflection curves. After a progressive debonding observed for both composites, a load drop was recorded at the end of the debonding process for the hot isostatic pressed (HIPed) composite whereas a smooth transition could be observed for the hot pressed composite. Another difference was found in the interfacial behavior of the composites during the purely frictional regime. Undulations in the frictional force were seen in the HIPed composite whereas a regular decrease of the friction load was observed in the hot pressed composite. Fiber roughness and thickness of the interphase materials are taken into account to qualitatively explain these differences
Godkänd; 1999; 20090701 (andbra)