HOOP TENSILE-STRENGTH AND FRACTURE-BEHAVIOR OF CONTINUOUS FIBER CERAMIC COMPOSITE (CFCC) TUBES FROM AMBIENT TO ELEVATED-TEMPERATURES

presently, continuous-fiber ceramic composites (CFCCs) are considered leading candidate materials for many high-temperature applications, su ch as high-pressure heat exchangers, radiant burner tubes, and engine combustors. To adequately evaluate these materials in their cylindrica l configurations, a hoop tension test is needed. A hydrostatic pressur ized test was developed to obtain the hoop tensile strength from ambie nt to elevated temperatures (>1500 degrees C). The method allows only hydrostatic pressure to develop inside the cylinder to cause failure f rom a hoop tensile stress. This test method evolved from testing monol ithic ceramics to continuous-fiber ceramic matrix composite (CMC) tube s. The results of early hydrostatic rests are briefly reviewed. A high light of one test identified fiber tow pull-out at 1000 degrees C wher e the tube indicated localized aneurysm-type deformation. Another CFCC material system, evaluated at room temperature, exhibited fiber pull- out on the order of 5 to 7 mm. The circumferential elastic modulus was also obtained.