Flexural Creep of Coated SiC‐Fiber‐Reinforced Glass‐Ceramic Composites

Publisher Website
Google Scholar
Abstract
This study reports the flexural creep behavior of a fiber‐reinforced glass‐ceramic and associated changes in micro‐structure. SiC fibers were coated with a dual layer of SiC/BN to provide a weak interface that was stable at high temperatures. Flexural creep, creep‐rupture, and creep‐strain recovery experiments were conducted on composite material and barium‐magnesium aluminosilicate matrix from 1000° to 1200°C. Below 1130°C, creep rates were extremely low (∼10−9 S−1), preventing accurate measurement of the stress dependence. Above 1130°C, creep rates were in the 10−8 s−1 range. The creep‐rupture strength of the composite at 1100°C was about 75–80% of the fast fracture strength. Creep‐strain recovery experiments showed recovery of up to 90% under prolonged unloading. Experimental creep results from the composite and the matrix were compared, and microstructural observations by TEM were employed to assess the effectiveness of the fiber coatings and to determine the mechanism(s) of creep deformation and damage.