MOSI2/SIC FIBER REINFORCED COMPOSITES FOR HIGH PERFORMANCE STRUCTURAL APPLICATIONS

THE MAIN OBJECTIVE OF THIS PROPOSED PROGRAM IS TO DEVELOP THE TECHNOLOGY FOR FABRICATING HIGH TEMPERATURE, HIGH OXIDATION RESISTANTS MOSI2/SIC FIBER REINFORCED CERAMIC STRUCTURES VIA A SCALABLE AND COST EFFECTIVE CHEMICAL VAPOR DEPOSITION (CVD) + HOT ISOSTATIC-PRESSING PROCESSES. IN PHASE I, THE FEASIBILITY OF FABRICATING A HIGH PERFORMANCE MOSI2/SIC COMPOSITE VIA A SCALABLE CVD PROCESS WILL BE ESTABLISHED. SMALL SAMPLES OF THE COMPOSITE WILL BE FABRICATED BY COATING SIC FIBERS BY CVD AND THEN HIP'ING THE FIBERS IN MOSIC MATRIX SUCH THAT LARGE COMPRESSIVE STRESSES ARE PRODUCED ON THE COMPOSITE SURFACE. THE COMPOSITE MATERIAL WILL BE CHARACTERIZED FOR IMPORTANT PROPERTIES SUCH AS DENSITY HARDNESS, FLEXURAL STRENGTH, FRACTURE TOUGHNESS AND THERMAL EXPANSION COEFFICIENT. FINALLY, ANALYTICAL UNDERSTANDING OF THE COMPOSITE AND THE CVD + HIP PROCESS PARAMETERS WILL BE DEVELOPED TO PROVIDE PROCESS SCALING TO LARGE SIZES AND TO OTHER MATERIALS.