Microcrack Toughening in a SiC-TiB_2 Composite

Abstract

Transmission electron microscopy observations of a fractured SiC-TiB_2 composite have provided conclusive evidence of stress-induced microcracking in this system. The microcrack density parameter around a steadily growing crack has been measured as a function of the distance from the crack plane. Microcrack toughening in this system has been assessed using a discrete model based on the measured microcrack density parameter. The computation results indicate that nearly half of the toughening arises from stress-induced microcracking. Other possible toughening mechanisms are also discussed.