Accession Number : ADA301872

Title :   Mechanical Properties of Porous, High Temperature Structural Materials: Sources of Toughness in Reaction Bonded Silicon Nitride.

Descriptive Note : Final rept. 1 May 91-31 Jan 95,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Argon, Ali S. ; Haggerty, John S.

PDF Url : ADA301872

Report Date : 15 OCT 1995

Pagination or Media Count : 178

Abstract : Reaction bonded silicon nitride (RBSN) prepared from submicron size pure silicon powder is a micro-porous ceramic with excellent mechanical and dielectric properties for high temperature structural applications and for radomes. In this research program the mechanical properties including elastic moduli, tensile strength and fracture toughness of RBSN was experimentally studied in connection with its quasi-regular microstructure. The further ranges of microstructural features and the processes related to local fracture resistance were studied by means of two relate and quite flexible computer simulations of the reaction kinetics controlling the microstructure and the processes that control the crack paths. These results are summarized and presented in greater detail in four appended manuscripts. jg p1

Descriptors :   *MECHANICAL PROPERTIES, *TENSILE STRENGTH, *REACTION KINETICS, *STRUCTURAL PROPERTIES, *HIGH TEMPERATURE, *RESISTANCE, *MODULUS OF ELASTICITY, *TOUGHNESS, *FRACTURE(MECHANICS), *DIELECTRIC PROPERTIES, *POROUS MATERIALS, *CONSTRUCTION MATERIALS, *SILICON NITRIDES, COMPUTERIZED SIMULATION, SOURCES, MICROSTRUCTURE, CRACKS, PATHS, CERAMIC MATERIALS, CHEMICAL REACTIONS, BONDING, RADOMES.

Subject Categories : Inorganic Chemistry
      Ceramics, Refractories and Glass
      Construction Equipment, Materials & Supplies
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE