Spatially varied interfaces
- National Inst. of Standards and Technology-Wright Lab., Dayton, OH (United States)
- SYSTRAN Co., Dayton, OH (United States)
Titanium matrix composites (TMCs) are a class of high specific strength/stiffness, intermediate temperature composites being developed for use in next-generation aircraft turbine engine components including bladed rings and actuator rods. TMCs excellent properties arise from the combination of the high strength titanium alloy matrices with ultra high strength/stiffness SiC fibers. The fiber/matrix interface has dual roles in unidirectionally reinforced TMCs: It transfers load from matrix to fiber, and it protects the fiber by deflecting oncoming cracks from the matrix away from the fiber, to the fiber matrix interface. Current composite interfaces are intentionally spatially uniform along the length of the fiber and around its circumference, although they may consist of several layers of coatings. Interface mechanical properties can be, and are tailored to be strong, such as SiC{sub f}/Ag/Ta/Ti-25Al-10Nb-3V-1Mo or weak, such as the SCS-6 carbon-rich coating. Reynolds, et al. coated Saphikon sapphire fibers (134 {micro}m diameter) with a porous oxide and incorporated them into a superalloy matrix. The nanometric scale of the pores was much less than the fiber diameter, and actually less than the thickness of the fiber coating. Size scale is an issue when considering crack propagation and fracture mechanics along the composite interface, where weakly bonded areas should be of the order of the fiber diameter to have an impact.
- OSTI ID:
- 271587
- Journal Information:
- Scripta Materialia, Vol. 35, Issue 3; Other Information: PBD: 1 Aug 1996
- Country of Publication:
- United States
- Language:
- English
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