LOW-COST MOLYBDENUM DISILICIDE MATRIX COMPOSITES

FIBER-REINFORCED AND WHISKER-REINFORCED MOLYBDENUM DISILICIDE (MOSI2) MATRIX COMPOSITES HAVE BEEN INDENTIFIED AS EXCELLENT CANDIDATES FOR HIGH TEMPERATURE STRUCTURAL APPLICATIONS IN OXIDIZING ENVIRONMENTS. HOWEVER, THE ROOM TEMPERATURE FRACTURE TOUGHNESS AND HIGH TEMPERATURE YIELD AND CREEP STRENGTH OF THESE MATERIALS CAN STILL BE DRASTICALLY IMPROVED, AND PROCESSING ISSUES MUST BE RESOLVED. RESEARCHERS ARE DEMONSTRATING THE FEASIBILITY OF SEVERAL FABRICATION METHODS FOR MOSI2 MATRIX COMPOSITES THAT ARE CAPABLE OF ELIMINATING THE MAJOR SOURCES OF PROCESSING FLAWS, AND OF GREATLY INCREASING PROCESS REPEATABILITY AND COST-EFFECTIVENESS WHILE ENHANCING MECHANICAL PROPERTIES. MOSI2/COATED SIC WHISKER COMPOSITS AND MOSI2-INFILTRATED FIBERS ARE BEING FABRICATED BY CHEMICAL VAPOR DEPOSITION (CVD) WITH SEVERAL ALLOY MICROSTRUCTURES, FOLLOWED BY PROPERTIES MEASUREMENTS. THESE RESULTS ARE COMPARED TO AVAILABLE DATA FOR SIC/MOSI2, C/C, AND C/SIC MATERIALS, AND AN ANALYSIS OF COST, RELIABILITY, FABRICABILITY, AND PERFORMANCE CONDUCTED.