Mechanical property characterization of fiber-reinforced SiC matrix composites

Abstract

Mechanical properties of Nicalon-fiber-reinforced silicon carbide (SiC) matrix composites fabricated by a forced chemical vapor infiltration (CVI) process have been measured and compared with properties of composites fabricated by a conventional isothermal process. Flexure strengths, tensile strengths, and fracture toughnesses measured at room temperature and flexure strengths measured at high temperatures are nearly identical for composites fabricated by the two processes provided that hot-face temperatures 1200{degree}C because of the degradation in strength of Nicalon fibers. Composites reinforced with more stable Tyranno fibers were fabricated by forced CVI and exhibited mechanical properties similar to those of Nicalon-reinforced composites. Composites reinforced with Tyranno fibers also exhibited improved high-temperature strengths. 33 refs., 7 figs., 6 tabs.