Elevated‐Temperature Toughening Mechanisms in a SiC w /Al 2 O 3 Composite

Crack growth resistance studies of a Sic‐whisker‐reinforced Al 2 O 3 ‐matrix composite have been correlated with the composite microstructure to determine the active fracture toughening mechanism, at each of three test temperatures through 1400°C. Evidence of cumulative toughening at all temperatures, as reported in the literature, was validated by R ‐curves; however, isolation of the following wake zone effects from that of the frontal process zone elicits a departure from published assumptions. A frontal zone mechanism, presumably microcrack toughening, dominates at room temperature, while a following wake zone mechanism of crack face whisker‐bridging controls at temperatures near 1200°C.