COMPRESSIVE SURFACE STRENGTHENING OF WHISKER REINFORCED COMPOSITES

THE DEVELOPMENT OF WHISKER REINFORCED STRUCTURAL CERAMICS WITH SUPERIOR MECHANICAL PROPERTIES HAS BEEN LIMITED BY STRENGTH CONTROLLING FLAWS WHICH ARE OFTEN PRESENT ON THE SURFACE. THE PRESENCE OF A COMPRESSIVE SURFACE LAYER IS KNOWN TO BE EFFECTIVE IN PREVENTING GROWTH OF THESE FLAWS. HOWEVER, TECHNIQUES WHICH HAVE HERETOFORE BEEN UTILIZED HAVE BEEN INEFFECTIVE IN THAT THE IMPROVEMENT IN MECHANICAL PROPERTIES IS NOT MAINTAINED TO HIGH TEMPERATURES AND THE PROCESSING EMPLOYED IS PRONE TO INTRODUCING ADDITIONAL FLAWS. THE TECHNIQUE PROPOSED HERE HAS NEITHER OF THESE DISADVANTAGES AND RESULTS IN IMPROVEMENTS IN BOTH STRENGTH AND FRACTURE TOUGHNESS TO AT LEAST 1400¿C. THIS PROCESS INVOLVES THE CONTROLLED OXIDATION OF A1(2)0(3)-ZRO(2)-SIC(W) COMPOSITES TO PRODUCE A COMPRESSIVE SURFACE LAYER ON A SAMPLE OF ANY SIZE OR SHAPE. PRESSURELESS SINTERING OF THESE COMPOSITES WILL BE INVESTIGATED SO THAT FABRICATION OF HIGH STRENGTH COMPLEX SHAPE STRUCTURAL CERAMICS WILL BE POSSIBLE. ANTICIPATED BENEFITS/POTENTIAL APPLICATIONS - THE DEVELOPMENT OF A PROCESS TO ENHANCE THE PROPERTIES OF CERAMIC COMPOSITES AND INCREASE THEIR RELIABILITY WILL RESULT IN THE WIDESPREAD USE OF CERAMICS AND COMPOSITES. APPLICATIONS FOR THESE SUPERIOR PROPERTY COMPOSITES WILL INCLUDE ARMORS, HEAT ENGINE COMPONENTS, AND LOAD BEARING STRUCTURE PARTS FOR AEROSPACE APPLICATIONS.