Accession Number : ADA188526

Title :   Microdesigning of Lightweight/High Strength Ceramic Materials.

Descriptive Note : Final technical rept. 30 Sep 83-30 Nov 86,

Corporate Author : WASHINGTON UNIV SEATTLE DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Aksay, I A

PDF Url : ADA188526

Report Date : 30 Aug 1987

Pagination or Media Count : 307

Abstract : The overall objective of the program has been concerned primarily with the processing and characterization of low density and high strength ceramic matrix composites for structural applications. In order to achieve this goal, three main task areas have been emphasized: (i) fundamental studies in processing, (ii) processing of ceramic/metal composites, and (iii) theoretical studies. The work in the first task area consisted of experimental studies on phase transitions in colloidal systems and microstructure/nanostructure evolution during sintering. These studies dealt with the dispersion, consolidation, and sintering of ceramic powders and ceramic forming gels, in an effort to provide a fundamental understanding of key processing parameters that affect the microstructure of the material. The key contribution of these studies has been the recognition of the fact that colloidally consolidated particle compacts display hierarchical clustering due to multiple site nucleation and growth of particle clusters. Consequently, such hierarchically clustered structures display a multimodal void size distribution. The work in the second task area saw development of techniques for processing a new class of particulate based and low density ceramic metal composites composed of boron carbide aluminum and aluminum diboride aluminum composite materials. These materials exhibited high fracture toughness high fracture strength and high hardness.

Descriptors :   *CERAMIC MATERIALS, *METAL MATRIX COMPOSITES, ALUMINUM, BORON CARBIDES, CLUSTERING, COLLOIDS, EXPERIMENTAL DATA, GELS, GROWTH(GENERAL), HARDNESS, LOW DENSITY, MICROSTRUCTURE, NUCLEATION, PARTICLES, PHASE TRANSFORMATIONS, POWDERS, PROCESSING, SINTERING, SITES, STRUCTURAL PROPERTIES

Subject Categories : Ceramics, Refractories and Glass
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE