A systematic study has been performed of the use of the Indentation Flexure
Fatigue (IFF) method to study crack growth in mullite at room temperature
and high temperature (1300 degreesC). The results obtained for a mullite ha
ve been compared with previous data generated on the same material, but usi
ng the more direct compact tension method. The material produces transgranu
lar crack growth and consequently does not show R-curve behaviour, which co
nsiderably simplifies the comparison of the data generated by both methods.
The IFF method can significantly overestimate the crack tip stress intensi
ty factor because of the way in which the residual stress intensity produce
d by the indentation is estimated. The experimental details that influence
the test results were investigated. (C) 2000 Elsevier Science Ltd. All righ
ts reserved.