Multiple-Laboratory Round-Robin Study of the Flexural, Shear, and Tensile Behavior of a Two-Dimensionally Woven Nicalon™/Sylramic™ Ceramic Matrix Composite

Abstract

A round-robin study was conducted on the flexural, shear, and tensile mechanical behavior of a Nicalon™ fiber-reinforced Sylramic™ matrix CFCC continuous fiber ceramic composite (CFCC) to: 1) determine the precision and bias of three ASTM test methods at room temperature for flexure, shear and tension [Test Method for Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramics (C 1341), Test Method for Shear Strength of Continuous Fiber-Reinforced Advanced Ceramics at Ambient Temperatures (C 1292), and Test Method for Monotonic Tensile Strength Testing of Continuous Fiber-Reinforced Ceramic Composites with Solid Rectangular Cross-Sections at Ambient Temperatures (C 1275)]; 2) establish an expansive data base (e.g., Mil-Hdbk-17 CMC effort) for a single CFCC; and 3) evaluate a statistically- significant sample size of a single CFCC for processing and design purposes. The commercial CFCC was comprised of eight plies of ceramic grade Nicalon™ fiber fabric in a symmetric 0/90 lay-up, a proprietary boron-containing interphase, and a silicon nitrocarbide matrix (Sylramic™) derived from polysilazane. Ten each of flexure, in-plane tension, in-plane (Iosipescu) shear, and interlaminar (double notch compression) test specimens were tested by each of seven to ten different laboratories per the applicable ASTM test method for totals of sixty to one hundred replicate tests for each test type. With a few exceptions, coefficients of variation for repeatability and reproducibility ranged from 5 to 10%.