Fracture behavior of 3-d Braided Nicalon/Silicon Carbide Composite

1988 ◽  
Vol 120 ◽  
Author(s):  
J.-M. Yang ◽  
J.-C. Chou ◽  
C. V. Burkland
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Thermal Shock Resistance ◽  
Fracture Behavior ◽  
Ceramic Composite ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Fiber Architecture ◽  
Structural Ceramic ◽  
Shock Resistance

AbstractThe fracture behavior of a 3-D braided Nicalon fiber-reinforced SiC matrix composite processed by chemical vapor infiltration (CVI) has been investigated. The fracture toughness and thermal shock resistance under various thermomechanical loadings have been characterized. The results obtained indicate that a tough and durable structural ceramic composite can be achieved through the combination of 3-D fiber architecture and the low temperature CVI processing.

Ceramic Matrix Composite Vane Subelement Fabrication

2004 ◽  
Author(s):  
Anthony Calomino ◽  
M. Verrilli
Keyword(s):  
Silicon Carbide ◽  
Ceramic Composite ◽  
Ceramic Matrix Composite ◽  
Chemical Vapor ◽  
Suction Side ◽  
Aircraft Engine ◽  
Chemical Vapor Infiltration ◽  
Thin Wall ◽  
Trailing Edge ◽  
Infiltration Process

Vane subelements were fabricated from a silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC) composite and were coated with an environmental barrier coating (EBC). In order to address realistic critical design features of a turbine airfoil, the vane subelement cross section was derived from an existing production aircraft engine vane. A new fabrication technique has been developed at NASA Glenn Research Center that enables ceramic composite vanes to be constructed using stoichiometric SiC fiber in the form of a two dimensional cloth. A unique woven cloth configuration was used to provide a sharp trailing edge with continuous fiber reinforcement. Fabrication of vanes with a sharp trailing edge was considered to be one of the more challenging features for fabricating a ceramic composite vane. The vanes were densified through the chemical vapor infiltration/slurry cast/silicon melt-infiltration process. Both NDE inspection and metallographic examinations revealed that the final as-fabricated composite quality of the vanes was consistent with that typically obtained for the same composite material fabricated into flat panels. Two vane configurations were fabricated. One consisted of a thin wall (1.5 mm) shell with a continuously reinforced sharp trailing edge. The second vane configuration included a reinforcing web bridging the pressure and suction-side vane walls and the same reinforced sharp trailing edge. This paper will discuss the vane fabrication and characterization efforts.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

STUDIES OF THERMAL SHOCK RESISTANCE OF AN ANTI-OXIDATION COATING FOR A MULTI-LAYERED CERAMIC COMPOSITE

2021 ◽  
pp. 51-58
Author(s):  
B.E. Goncharov ◽  
◽  
A.M. Sipatov ◽  
N.N. Cherkashneva ◽  
A.Yu. Pleskan ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Gas Flow ◽  
Ceramic Composite ◽  
Fuel Gas ◽  
Refractory Compounds ◽  
Turbojet Engine ◽  
Shock Resistance ◽  
Layered Ceramic ◽  
High Thermal Shock Resistance

The article covers the performance of thermal shock resistance experiments of a ceramic composite with two types of anti-oxidation coatings. A thermal shock burner rig was used to carry out the experiments similar to those expected in a combustor of a turbojet engine. SEM and х-ray diffraction analyses were used to examine the antioxidation coatings. It was deter-mined that the coating based on the refractory compounds possesses high thermal shock resistance when exposed to the fuel gas flow from a burner rig.

Thermal Shock Resistance and Fracture Behavior of ZrB2-Based Fibrous Monolith Ceramics

2009 ◽  
Vol 92 (1) ◽  
pp. 161-166 ◽  
Author(s):  
James W. Zimmermann ◽  
Gregory E. Hilmas ◽  
William G. Fahrenholtz
Keyword(s):  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Fracture Behavior ◽  
Shock Resistance
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