MICROSTRUCTURAL DEVELOPMENT OF SCS-6 SIC FIBERS DURING HIGH-TEMPERATURE CREEP

Microstructural development of SCS-6 SiC fibers induced by creep defor mation at 1400 degrees C is presented. Grain growth occurs in all SiC regions of the fiber during creep. Portions of the SiC4 region transfo rm from beta SiC to alpha SiC growing at the expense of the beta SiC T he SiC1 through SiC3 regions of the fiber consist of a distinct (C + b eta SiC) two-phase region. The grain growth of the beta SiC grains in the two-phase region is not as extensive as in the SiC4 region, sugges ting that the presence of excess carbon may inhibit the growth of beta SiC.