Design Guidelines for In‐Plane Mechanical Properties of SiC Fiber‐Reinforced Melt‐Infiltrated SiC Composites

Abstract

In-plane tensile stress-strain, tensile creep, and after-creep retained tensile properties of melt-infiltrated SiC-SiC composites reinforced with different fiber types were evaluated with an emphasis on obtaining simple or first-order microstructural design guidelines for these in-plane mechanical properties. Using the mini-matrix approach to model stress-strain behavior and the results of this study, three basic general design criteria for stress and strain limits are formulated, namely a design stress limit, a design total strain limit, and an after-creep design retained strength limit. It is shown that these criteria can be useful for designing components for high temperature applications.

Mechanical properties and real-time damage evaluations of environmental barrier coated SiC/SiC CMCs subjected to tensile loading under thermal gradients

“…The fiber area is estimated as the area of a single fiber, multiplied by the number of fibers in a fiber-tow, number of tows per ply and number of plies in the composite lay-up [25].…”

Fiber‐Reinforced Ceramic Matrix Composites for Aero Engines

“…The type and amount of fibers in the composite will of course have a strong effect on the composite properties. Figure 2 shows woven composites of similar fiber architecture (five-harness satin) with different types of fractions of fibers in the loading direction (Morscher and Pujar, 2009). For these nonoxide or SiC-based CMCs, it is useful to view CMCs as fiber-dominated or matrix-dominated, which is determined by the load-carrying ability of the matrix and the matrix-processing technique as well as the fiber structure or architecture, that is, laminate or textile (woven).…”

“…It is critical that accurate location of the sources of these waves be determined, which is possible when using multiple sensors and large band gap frequency Morscher, 2004) sensors so that the different modes of the waveforms, especially the high-frequency extensional mode, can be identified. For matrix-dominated SiC matrix composites, AE has been used to quantify the formation and growth of matrix cracks in the composite, which can be directly correlated with the stress-dependent density of matrix cracks in the composite (Figure 8) (Morscher, 2004;Morscher and Pujar, 2009).…”

In situ imaging and strain determination during fracture in a SiC/SiC ceramic matrix composite

“…The net sample section between the notches is (3.5 Â 2.0) mm 2 , which at the highest load corresponds to a net stress of 130 MPa and a linear elastic stress of $390 MPa since the stress concentration factor is approximately 3.1 in this geometry [15]. This value is well over the proportional limit of 180 MPa measured in these composites, which corresponds to $700 le using E = 260 GPa [16,17] for the macroscopic Young's modulus of the composite. Measured, volume-averaged strains in the near-notch region range from 900-1200 le for the load-bearing fraction of the sample (twice what is observed in Fig.…”