Determination of Interfacial Properties Using a Single‐Fiber Microcomposite Test

Abstract

A single‐filament microcomposite consisting of 143‐μm‐diameter CVD SiC, a thin “interfacial” coating, and a thick (130–160 μm) CVD SiC matrix sheath was tested in tension to determine the interfacial shear properties of carbon and BN interfacial coatings. Load/displacement and acoustic emission were used to determine the mechanical behavior of the microcomposites and matrix cracking. Optical and electron microscopy were performed to confirm the extent and nature of matrix cracking and to analyze the micro‐composite microstructure. The interfacial properties were determined from matrix cracking and load/displacement hysteresis techniques. Direct measurement of the interfacial sliding stress from push‐out and pull‐out experiments were in good agreement with two of the three microcomposite systems studied.

Damage Classification of Sandwich Composites Using Acoustic Emission Technique and k-means Genetic Algorithm

“…Therefore it is very important to discriminate AE signals corresponding to different failure mechanisms. In order to find the correlation between damage mechanisms and AE parameters, several studies have been carried out using different AE features such as counts, amplitude, energy [10,11,12]. Also, multi-parameter analysis has been used by several researchers to improve discrimination of AE events [13,14,15].…”

Fiber Effects on Minicomposite Mechanical Properties for Several Silicon Carbide Fiber‐Chemically Vapor‐Infiltrated Silicon Carbide Matrix Systems

“…3), because of the large flaws in the matrix. Most likely, there is some variability in the matrix volume fraction along the length, and initial fracture occurs at regions with greater matrix fractions (this was observed for single-fiber microcomposites 29 ). Cracking eventually stops in these weak matrix regions for the Nic-3MBN and HN-PBN minicomposites, because the low interfacial shear stress blocks ''large'' regions of matrix from greater amounts of stress.…”

Compatibility of interfaces and fibers for SiC-composites in fusion environments

“…This is problematic since the interphase that will be selected is not known so we assume a thin pyrocarbon interphase with interfacial shear strength of 15 MPa as suggested by the bridging model. We consider interactions between the environment and the interphase that cause an increase in bonding [44][45][46][47][48][49][50][51] and use the static bridging model to calculate fracture toughness due to changes in the interfacial shear strength. Fig.…”