9632823 Lackey The objective of the proposed research is to study the interrelationships between the processing, structure, and properties of a new class of ceramic matrix composites. These new composites consist of a reinforcement phase plus a matrix composed of alternate thin layers of two different materials. Layered structures are known to enhance mechanical toughness, and thus, their use as the matrix, along with the reinforcement phase, should enhance the toughness of the overall composite. The 3 year project consists of composite processing, characterization, and mechanics modeling. The process-structure-property interrelationships for several laminated matrix composite systems will be studied. Fibers of interest are carbon, SiC, and Al2O3. Matrix materials will be selected from carbon, SiC, Si3N4, Al2O3, mullite, B13C2, Nb, and Re. Based on the results from the first two years, a preferred system will be selected for detailed study and optimization in the third year. We propose to identify the layer thicknesses and material properties (thermal expansion, elastic modulus, and strength) required to optimize the mechanical performance, particularly fracture toughness and strength, of this new class of composites. %%% The objective of the proposed research is to study the interrelationships between the processing, structure, and properties of a new class of ceramic matrix composites. These new composites consist of a reinforcement phase plus a matrix composed of alternate thin layers of two different materials. Layered structures are known to enhance mechanical toughness, and thus, their use as the matrix, along with the reinforcement phase, should enhance the toughness of the overall composite. Improvement of the properties of ceramic matrix composites will have a large impact on many commercial and defense systems. ***
