THE PHYSICS OF MMC'S: MICROSTRUCTURAL EFFECTS

THIS PHASE I PROGRAM WILL CHARACTERIZE AND DEMONSTRATE THE EFFECTS ON STATIC MECHANICAL PROPERTIES AND COMPOSITE TOUGHNESS OF FINE GRAIN SIZE MICROSTRUCTURE OF GRANULAR STRUCTURE COMPOSITES WITH ISOTROPIC CHARACTERISTICS. PRESENT CERMETS AND DISCONTINUOUSLY REINFORCED METAL-MATRIX COMPOSITE MATERIALS ARE BING PRODUCED VIA A PROCESS THAT INCLUDES A MECHANICAL MIXING STEP TO COMBINE AND RANDOMLY ORIENT THE CONSTITUENTS. THIS PROJECT WILL UTILIZE BASIC COMPOSITE PROCESSING TECHNOLOGY WITH A FINE AND A COARSE FORM OF CERAMIC REQUIREMENT, A FINEGRAIN AND COARSEGRAIN MATRIX, AND OPEN-PORE CERAMIC AND METAL MAT MATERIALS. SUBSEQUENT PROCESSING STEPS WOULD BE SIMILAR TO PRESENT COMPOSITE-FABRICATION TECHNIQUES, BUT EMPHASIZING UNIFORM, FINEGRAINED, OR COARSEGRAIN RESULTANT MICROSTRUCTURE. INITIAL MAT REINFORCEMENT CHARACTERISTICS CAN BE USED TO CREATE SKELETAL FORMS (A DISCONTINUOUS FILAMENTARY PHASE) AND TO ENABLE INCORPORATION OF DISSIMILAR-PHASE OR MATRIX MATERIAL, INTO THE COMPOSITE. PLATES OF COARSE AND FINE REINFORCEMENTS AND MATRICES WILL BE FABRICATED FOR SEM EVALUATION AND BASIC MECHANICAL TESTS. THIS PROGRAM WILL BOUND MICROSTRUCTURAL GRAIN SIZE EFFECTS AND OFFER VERSATILITY BEYOND PRESENT COMPOSITE PROCESSING SYSTEMS. SINCE A WIDE VARIETY OF CERAMIC, GRAPHITIC, METAL AND/OR ORGANIC MAT AND FOAM IS AVAILABLE, BY APPROPRIATE PROCESSING, THE MATERIALS' UNIQUE CHARACTERISTICS CAN BE DESIGNED INTO THE MMC SYSTEM.