Creep and Fatigue Behavior in an Enhanced SiC/SiC Composite at High Temperature

Abstract

The monotonic tension, creep, and fatigue behavior of an enhanced SiC/SiC composite was investigated at a temperature of 1300°C in air and argon. The improved creep and fatigue resistances were determined and compared to those of the standard SiC/SiC composite. The effects of additives (glass-forming, boron-based particulates) in the matrix on the creep and environmental resistance of the enhanced SiC/SiC composite were discussed. Crack propagation in the matrix of the enhanced SiC/SiC composite was different from that in the standard SiC/SiC composite. The filling of the glassy phases in the cracks prohibited the diffusion of oxygen from the environment. As a result, creep and fatigue properties in the enhanced SiC/SiC composite in air at high temperatures was improved.

Creep damage resistance of ceramic–matrix composites

“…[6][7][8][9][10][11] Thus, as illustrated by the ε/t trajectories for the HNSiC f -SiBC material in Fig. 1, following the initial loading strain, the creep rate decays continuously, reaching a minimum rate (ε m ) just prior to failure.…”

“…Comparisons of the stress/creep life relationships for SiC f well as for SiC f -SiC,6,9 SiC f -SiBC,10 HNSiC f -SiC11 and HNSiC f -SiBC samples tested in air at 1300 • C.…”

Fatigue Behavior of Ceramic Matrix Composite Oxidized at Intermediate Temperatures

“…A glass-forming, boron-based particulates that react with oxygen were added to the SiC-matrix to produce a sealant glass that inhibits oxidation of carbon layer. 5,6) The composite, processed as 200 Â 200 mm panels with a thickness of 3.4 mm, contained 40 vol% Nicalon fibers and 10% porosity. The average diameter and tensile strength of fibers were about 12 mm and 3.0 GPa, respectively.…”

“…4,5) A modified SiC/SiC is fabricated by adding glassy phases in the matrix, which is called the enhanced SiC/SiC. 6,7) At temperatures above 1200 C, creep and fatigue properties of the enhanced SiC/ SiC in air are quite good. However, the pest phenomenon cannot be improved since the glassy phases are not able to seal cracks at intermediate temperatures.…”

Creep of Hi-Nicalon S Ceramic Fiber Tows at 800 deg C in Air and in Silicic Acid-Saturated Steam

“…Monkman-Grant plots, log-log plots of creep rupture time vs creep rate, showed the characteristic parallel lines at different temperatures and closely matched empirical creep rupture data of SiC/SiC composites from Zhu et al [191,192] Due to the benefits of using the Monkman-Grant relationship, it is worthwhile to investigate whether it applies to Hi-Nicalon T M S fiber tows and can be used to predict their creep lifetime. In this section, the Monkman-Grant relationship is evaluated for…”