Characterization of fatigue damage modes in nicalon/calcium aluminosilicate composites

High-cycle fatigue behavior of Nicalon (TM) fiber-reinforced calcium aluminosilicate (CAS) glass-ceramic matrix composites (Nicalon (TM)/CAS) was investigated with the aid of a nondestructive evaluation (NDE) technique. Infrared (IR) thermography was employed to study two different types of Nicalon (TM)/CAS composites: crossply and unidirectional specimens. During fatigue testing, an IR camera was used for in-situ monitoring of temperature evolution of Nicalon (TM)/CAS samples. Stress versus cycles to failure curves were generated for predicting the lifetime of Nicalon (TM)/CAS composites, and the IR camera measured the temperature changes during high-cycle fatigue testing. Microstructural characterizations using scanning electron microscopy (SEM) were performed to investigate fracture modes and failure mechanisms of Nicalon (TM)/CAS samples. In this study, the NDE technique and SEM characterization were used to facilitate a better understanding of damage evolution and progress of Nicalon (TM) CAS composites during high-cycle fatigue.