Testing the tensile properties of ceramic-matrix composites

Mechanical Behavior at 20° and 1200°C of Nicalon‐Silicon‐Carbide‐Fiber‐Reinforced Alumina‐Matrix Composites

“…This degradation also was reported by Woodford et al, 11 who evaluated the tensile properties in air at 20°and 1000°C of seven different FRCs, including one Al 2 O 3 -Nicalon-SiC composite that was processed by melt oxidation, which was similar to the one analyzed in this paper. The tensile strength of this material decreased from 260 MPa at 20°C to 120 MPa at 1000°C; however, its behavior at 1000°C was considered to present the best overall combination of properties among all the materials that were tested.…”

“…However, additional investigations showed that composite degradation also could be due to a reduction in the strength of the ceramic fibers, and various studies claimed that this mechanism was dominant over interface degradation in several composite systems. [10][11][12]14,15 The main cause of the composite degradation at elevated temperature remains an open question; in fact, the answer may change completely from one composite material to another. 16 Thus, the microstructural optimization of a composite material requires a detailed investigation to evaluate the critical parameters that control the strength and toughness, which are mainly the interface and the fiber properties.…”

“…The few experimental studies on the elevatedtemperature mechanical behavior of FRCs have indicated that the environmental effects lead to an substantial decrease in the mechanical properties. [5][6][7][8][9][10][11][12][13][14][15][16] The origin of this degradation was initially attributed to the oxidation of the fiber/matrix interface, [5][6][7][8][9] and the processing efforts were intended to develop fiber/matrix interfaces that are able to withstand the chemical attack of the environment. However, additional investigations showed that composite degradation also could be due to a reduction in the strength of the ceramic fibers, and various studies claimed that this mechanism was dominant over interface degradation in several composite systems.…”

Distribution of fibre pullout length and interface shear strength within a single fibre bundle for an orthogonal 3-D woven Si–Ti–C–O fibre/Si–Ti–C–O matrix composite tested at 1100°C in air

“…8 Oxidation of the fibre/matrix interface 9 and exposed fibre surfaces [10][11][12][13] may increase τ to such an extent that crack deflection mechanisms at the fibre/matrix interface are suppressed, 14 leading to the formation of an embrittled region characterised by flat fibre fracture surfaces and negligible pullout lengths. 3,15 A related concern for CMCs containing fibres based on the silicon carbide (SiC) system is the formation of an oxide film at the fibre surface, 15 which acts as a flaw population and decreases fibre strength. 16 Modelling of the oxidation behaviour in CMCs based on the SiC/SiC system has indicated the maximum oxidation rate to occur at intermediate temperatures (e.g.…”

Effect of irradiation on thermal expansion of SiC{sub f}/SiC composites

“…However, monolithic Sic is not a suitable choice for structural applications due to its brittle nature. In contrast, Sic-fiber-reinforced/SiC-matrix (SiC,/SiC) composites have recently been shown to exhibit non-catastrophic failure modes analogous' to the plastic deformation exhibited by traditional metallic materials [1,2]. As a result, SiCf constituent materials, refinement of fabrication and processing methods, and characterization of the effect of irradiation on material properties.…”