A fiber damage model for early stage consolidation of metal-coated fibers
- Univ. of Virginia, Charlottesville, VA (United States)
Continuous fiber reinforced titanium matrix composites (TMCs) possess combinations of specific modulus, strength, and creep resistance that are well suited for a variety of aerospace applications. Recent studies of the high temperature consolidation of titanium alloy coated {alpha}-alumina fiber tows and SiC monofilaments have both revealed the widespread occurrence of fiber bending and fracture during early stage consolidation. This damage was shown to arise from the bending of unaligned fibers during consolidation and was found to be affected by the mechanical behavior of the metal-metal contacts at fiber crossovers. To predict the incidence of fiber fracture during early stage high temperature consolidation, a time-temperature dependent micromechanical model incorporating the evolving contact geometry and mechanical behavior of both the metal matrix and the ceramic fibers has been combined with a statistical representation of crossovers in the pre-consolidated layup. The damage predictions are found to compare favorably with experimental results. The model has subsequently been used to explore the effects of fiber strength, matrix constitutive properties and the processing conditions upon the incidence of fiber fracture. It reveals the existence of a temperature dependent pressurization rate below which fracture is relatively unlikely. This critical pressure rate can be significantly increased by the enhanced superplasticity of the initially nanocrystalline coating.
- Sponsoring Organization:
- Defense Advanced Research Projects Agency, Arlington, VA (United States); National Aeronautics and Space Administration, Washington, DC (United States)
- OSTI ID:
- 483614
- Journal Information:
- Acta Materialia, Vol. 45, Issue 3; Other Information: PBD: Mar 1997
- Country of Publication:
- United States
- Language:
- English
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