Accession Number : ADA327240

Title :   Materials Development Research.

Descriptive Note : Final rept. 28 Mar 92-30 Sep 96,

Corporate Author : UNIVERSAL ENERGY SYSTEMS INC DAYTON OH

Personal Author(s) : Mendiratta, Madan G. ; Mah, Tai-Il ; Subramanian, P. R. ; Majumdar, Bhaskar ; Woodward, Christopher

PDF Url : ADA327240

Report Date : NOV 1996

Pagination or Media Count : 189

Abstract : Research has been carried out in three materials areas: Advanced Metallics two systems -- Gamma-TiAl alloys and NbTi/silicide composites are being developed as high temperature structural materials. The research includes chemistry/processing/microstructure/property relations to provide a specific balance of mechanical properties. A physical vapor deposition system has been built to produce nanolayered and nanocrystalline materials. Quantitative models have been developed to describe the yield strength of gamma-TiAl alloys, metallic multilayers and nanocrystalline Al alloys. Theoretical work has been carried out, using a variety of analytical and computational tools, to predict fundamental aspects of plasticity and fracture on length scales connected to electronic, atomistic and continuum levels. Advanced Metallic Compositions research has involved SiC fiber/Ti matrix composites with focus on interface and matrix chemistry/microstructures to provide optimum mechanical properties. The interfaces were studied by testing composites containing only a few fibers while the matrix development involved chemistry and heat treatment optimization. Ceramic Matrix Composites work included studies on experimental mechanics, fiber coatings and oxide-oxide composites. Models were developed to study the effect of matrix roughness on fiber push out/pull out. Various fiber/matrix interface control concepts to weaken interfaces by oxidation resistant means were explored. Fugitive interface concept was successfully demonstrated on oxide-oxide composites.

Descriptors :   *METAL MATRIX COMPOSITES, *FRACTURE(MECHANICS), *HEAT TREATMENT, MECHANICAL PROPERTIES, ALUMINUM ALLOYS, INTERFACES, PHYSICAL PROPERTIES, CERAMIC MATRIX COMPOSITES, FIBER REINFORCED COMPOSITES, VAPOR DEPOSITION, POINT DEFECTS, CHEMISTRY, COATINGS, DISLOCATIONS, TITANIUM ALUMINIDE, REFRACTORY METALS, YIELD STRENGTH, GREENS FUNCTIONS, SILICIDES, ELECTRON MOBILITY, POLYCRYSTALLINE, NIOBIUM COMPOUNDS.

Subject Categories : Laminates and Composite Materials
      Mechanics
      Coatings, Colorants and Finishes

Distribution Statement : APPROVED FOR PUBLIC RELEASE