Creep Behavior and Modeling of SiC-Based PC Ceramic Matrix Composites with Glass Sealant in High Temperature Air

摘要

NAL, Ube Industries LTD, and Shikibo LTD have been conducting a joint R&D effort of several types of ceramic matrix composites (CMC) using Si-Ti-C-O (Tyranno®) fiber and 3-D fabrics reinforcement. The present report focuses on a CMC using polymer impregnation and pyrolysis (PIP) matrix. The final point of improvement is a glassy sealant technology for better oxidation resistance developed by Kawasaki Heavy Industries (KHI) LTD. By applying this sealant, static strengths in high temperature air up to 1200℃ were improved to be 90% of high temperature strengths in vacuum. Creep tests were also conducted and it was found that this CMC system with the sealant exhibits superb creep rupture time, 700 hours (4 weeks) at 140MPa and 200 hours at 180MPa in 1100℃ air, which is more than a doubled strength of the forerunner CVI-CMC. Some tests are also conducted at 1200° and 1000 and a relation based on Arrhenius type formula is examined. The indicated strength vs. creep time relationship demonstrates a superiority of the present material in a creep behavior. Creep strain rates were also measured for many specimens. An attempt was made for deduction of creep constitutive equation based on constitutive material properties.