Characterization of Failure Behavior of Brittle Matrix Composites; at Room and Elevated Temperatures

Abstract

In this study, a systematic tensile testing scheme was carried out on specimens made of unidirectional Nicalon/CAS II ceramic matrix composite with 30% and 40% fiber volume fractions to characterize the tensile failure behavior of brittle matrix composites at room and elevated temperatures. The tests were conducted inside the chamber of a scanning electron microscope (SEM). Utilizing an innovative in-situ tensile testing technique (1), the whole damage history of the specimen under continuous tensile loading was monitored through SEM and hardcopies showing the continuous damage accumulations in the specimens were captured using a video processor through a computer equipped with an Imaging Advanced Frame Grabber (AFG) digital imaging analyzer system. Finally, an analytical model which incorporates the observed damage progression and is based on the microstructure of the composite was developed.