Accession Number : ADA185549

Title :   Characterization of Mechanical Damage Mechanisms in Ceramic Composite Materials.

Descriptive Note : Technical rept. 24 May 86-23 May 87,

Corporate Author : SOUTHWEST RESEARCH INST SAN ANTONIO TX

Personal Author(s) : Lankford, James, Jr

PDF Url : ADA185549

Report Date : Aug 1987

Pagination or Media Count : 50

Abstract : Earlier work on compressive strength of glass-ceramic matrix SiC fiber-reinforced composites is extended to define their behavior at high strain rates, and to assess the role of matrix phase versus fibers under such conditions. It is shown that the composite material can possess extremely high strain rate hardening exponents for strain rates in excess of about 400/s. These uniquely rapid increases in strength are found to depend upon composite microstructure and its orientation relative to the load axis; specifically, such strengthening correlates with at least one major set of fiber bundles being parallel to the load axis. The latter fail by kink initiation and propagation, a highly strain rate dependent, temperature-independent process. For off-axis implusive-load situations, the pyroceram matrix itself plays a significant role in controlling failure. Keywords: Compressive strength; Partially stabilized zirconia; Temperature effects; Composite materials; Fracture Mechanisms; Ceramics; Plastic flow; Glass matrix Ceramics; Cavitation.

Descriptors :   *CERAMIC MATERIALS, *COMPOSITE MATERIALS, *STRENGTH(MECHANICS), BUNDLES, CAVITATION, COMPRESSIVE PROPERTIES, DAMAGE, FIBER REINFORCED COMPOSITES, FIBERS, FRACTURE(MECHANICS), GLASS, HIGH RATE, MATRIX MATERIALS, MECHANICAL PROPERTIES, MICROSTRUCTURE, PLASTIC FLOW, STABILIZATION, STRAIN RATE, TEMPERATURE, ZIRCONIUM OXIDES, STRESS STRAIN RELATIONS, SILICON CARBIDES, LITHIUM, ALUMINUM, SILICATES, SOLID PHASES, TITANIUM OXIDES

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE