Fatigue behavior of a cross-ply metal matrix composite at elevated temperature under the strain controlled mode
- Air Force Inst. of Tech., Wright Patterson AFB, OH (United States). Dept. of Aeronautics and Astronautics
A study was conducted to investigate the fatigue behavior of a cross-ply metal matrix composite subjected to fully-reversed, strain-controlled fatigue cycling at elevated temperature. The stress-strain response, maximum and minimum stresses, and modulus during cycling were analyzed to characterize the macro-mechanical behavior. Additionally, microscopy and fractography were conducted to identify damage mechanisms. Damage always initiated in the 90 deg plies, but the governing factor in the fatigue life was damage in the 0 deg plies. The dominant failure mode was fracturing of fibers in the 0 deg plies when the maximum strain was greater than 0.55%, but the dominant failure mode was matrix cracking when the maximum strain was less than 0.55%. Combining the fatigue life data with the macro-mechanical and microscopic observations, a fatigue life diagram was developed and partitioned into three regions. These regions showed relationships between the maximum applied strain and the dominant damage mechanisms. Also, on a strain range basis, the fatigue lives of the specimens tested under the strain-controlled mode in this study were compared with its counterpart under the load-controlled mode of the previous study. It was found that the fatigue lives for these two conditions were the same within the experimental scatter. The MMC tested in this investigation was the Ti-15V-3Cr-3Al-3Sn titanium alloy reinforced with 36 volume percent of silicon carbide fibers (SCS-6).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 543523
- Journal Information:
- Journal of Engineering Materials and Technology, Journal Name: Journal of Engineering Materials and Technology Journal Issue: 4 Vol. 119; ISSN 0094-4289; ISSN JEMTA8
- Country of Publication:
- United States
- Language:
- English
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