Thermomechanical fatigue behavior of a silicone-carbide fiber-reinforced calcium-aluminosilicate glass-ceramic matrix composite. Master's thesis
Ceramic matrix composites are being considered for use in advanced turbine engines and other applications where thermomechanical fatigue (TMF) conditions exist. Isothermal fatigue and in-phase TMF tests were performed on a unidirectional, continuous-fiber, Nicalon reinforced calcium aluminosilicate glass-ceramic material (O16, SiC/CAS-11). Monotonic tensile tests were performed at 1100 C (20120F) and 100 MPa/sec to determine the material's ultimate strength and proportional limit. Isothermal fatigue tests at 1100 C (20120F) employed two loading profiles, a triangular waveform with ramp times of 60 seconds, and a similar profile with a superimposed 60 second hold time at These tests used a maximum stress of 100 MPa (40% of ) R = 0.1. TMF loading profiles were identical to the isothermal loading profiles. During the TMF tests, the temperature was cycled between 500 and 1100 C(932 and 20120F) in time with the load. Run out was arbitrarily set at 1000 cycles for all fatigue profiles. All fatigued specimens reached run out and were tested in tension at 1100 C and 100 MPa/sec immediately following the isothermal and thermomechanical tests. Residual modulus, residual strength, hysteretic modulus, and strain accumulation were all explored as possible damage indicators. Strain accumulation appeared to be the parameter which allowed for the greatest distinction to be made among the types of tests performed. Stress analyses performed on the fiber and matrix material and creep data for the composite suggest that matrix creep is the primary source of damage in the isothermal and thermomechanical fatigue profiles investigated for this project.
- Research Organization:
- Air Force Inst. of Tech., Wright-Patterson AFB, OH (United States)
- OSTI ID:
- 5130164
- Report Number(s):
- AD-A-249870/7/XAB; AFIT/CI/CIA--91-126
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360603* -- Materials-- Properties
ALKALINE EARTH METALS
ALUMINIUM COMPOUNDS
ALUMINIUM NITRIDES
CALCIUM
CARBIDES
CARBON COMPOUNDS
CERAMICS
COMPOSITE MATERIALS
CREEP
DAMAGE
ELEMENTS
ENGINES
FATIGUE
FIBERS
GLASS
HYSTERESIS
MATERIALS
MATRIX MATERIALS
MECHANICAL PROPERTIES
METALS
NITRIDES
NITROGEN COMPOUNDS
PNICTIDES
SILICON CARBIDES
SILICON COMPOUNDS
THERMAL FATIGUE
ULTIMATE STRENGTH