Fiber effects on creep and cyclic durability of 3D woven SiC/SiC composites with a hybrid SiC matrix

Abstract

Creep and cyclic fatigue durability of 3D woven SiC-fiber-reinforced SiC-matrix composites with a hybrid SiC matrix and three types of SiC fibers was investigated from 1300 to 1482 °C in air at stresses up to 150 MPa. The fiber types investigated were Sylramic™-iBN, super Sylramic™-iBN, and Hi-Nicalon™-S SiC fibers, and the hybrid SiC matrix was fabricated from a combination of chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis. Results indicate that accumulated strain during creep and cyclic fatigue at low stresses is predominantly controlled by the CVI SiC matrix, but durability of the composites is influenced by the SiC fiber types as well as the CVI SiC matrix. Composites containing super Sylramic™-iBN SiC fibers showed better durability compared to the composites containing the other two types of fiber. Potential applications and challenges of using this composite for highly loaded turbine components are discussed.