Abstract
Acoustic emission (AE) was monitored during thermomechanical fatigue (TMF) tests conducted on a silicon carbide fiber, titanium alloy matrix composite, SCS-6/TIMETAL®21S. The tests were stress-controlled with a stress ratio of 0·1, and temperature was cycled from 150 to 650°C. In-phase and out-of-phase TMF cycling were characterized by distinct AE behavior. The rate of fiber fractures as indicated by AE during in-phase cycling was much higher than during out-of-phase cycling, correlating with metallography and micromechanics analyses which indicate that the fiber stress is higher under in-phase than out-of-phase cycling. The fiber fracture rate was proportional to the maximum fiber stress and remained nearly constant during most of the test. The rate was greater during the early cycling as well as near the end. AE also indicated that most of the early cyclic damage occurred during the initial loading.
Original language | English |
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Pages (from-to) | 1-8 |
Number of pages | 8 |
Journal | Composites Science and Technology |
Volume | 52 |
Issue number | 1 |
DOIs | |
State | Published - 1994 |
Keywords
- acoustic emission
- damage progression
- fiber fractures
- matrix cracking
- metal-matrix composites
- thermomechanical fatigue