Accession Number : ADA293776

Title :   In Situ Composites in the Aluminum Nitride-Alumina System.

Descriptive Note : Final rept. 19 Sep 94-19 Apr 95,

Corporate Author : QUEST INTEGRATED INC KENT WA

Personal Author(s) : Savron, Ender

PDF Url : ADA293776

Report Date : APR 1995

Pagination or Media Count : 33

Abstract : An attempt was made to produce in situ composites in an aluminum nitride-alumina system via pressureless reaction sintering. Different aluminum nitride-alumina compositions were prepared and fired at temperatures between 1900 deg C and 2200 deg C. Phase compositions were determined by x-ray diffraction, and microstructure development was evaluated by scanning electron microscopy. Elongated grains in an equiaxed matrix were achieved. However, the expected improvement in mechanical properties was offset by excessive grain growth and porosity. The high mobility of grain boundaries causes abnormal growth and pore entrapment without full densification. Suggestions for further work are offered to remedy the problems. jg

Descriptors :   *MICROSTRUCTURE, *COMPOSITE MATERIALS, *NITRIDES, *ALUMINUM OXIDES, *ALUMINUM, DENSITY, TEMPERATURE, MECHANICAL PROPERTIES, MOBILITY, SCANNING ELECTRON MICROSCOPES, HIGH RATE, POWDERS, X RAY DIFFRACTION, POROSITY, CHEMICAL COMPOSITION, ELECTRON MICROSCOPY, PRESSURE, GRAIN GROWTH, SPRAYS, ABNORMALITIES, DRYING, GRAIN BOUNDARIES, DISPERSIONS, ACTIVATED SINTERING.

Subject Categories : Laminates and Composite Materials
      Inorganic Chemistry
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE