Accession Number : ADA136242

Title :   Microhardness, Friction and Wear of SiC and Si3N4 Materials as a Function of Load, Temperature and Environment.

Descriptive Note : Annual technical rept. no. 3, 1 Oct 80-30 Sep 81,

Corporate Author : CAMBRIDGE UNIV (ENGLAND) DEPT OF METALLURGY AND MATERIALS SCIENCE

Personal Author(s) : Naylor,M G S ; Page,T F

PDF Url : ADA136242

Report Date : Oct 1981

Pagination or Media Count : 272

Abstract : Plasticity and fracture processes in engineering ceramics based on silicon carbide, silicon nitride, a sialon and boron carbide have been investigated as a function of temperature (in the range 25 - 1000 C) using indentation microhardness techniques. The effects of specimen microstructure on indentation processes were determined by using materials formed by a wide range of fabrication routes (sintering, hot-pressing, reaction-bonding and pyrolytic deposition) and comparison was made with the behaviour of single crystals (SiC and Si). Microstructural characterization was carried out by light microscopy, electron-optical and X-ray techniques. The variation of Vickers and, in some cases, Knoop microhardness with temperature was measured, and deformation structures around indentations were examined optically and by scanning electron microscopy. Indentation plasticity in silicon carbide was further investigated by measuring Knoop hardness anisotropy on basal and non-basal faces of single crystal SiC at various temperatures. The effect of dopant on hardness was investigated for Si and SiC.

Descriptors :   *Ceramic materials, *Microhardness, *Mechanical properties, Silicon carbides, Silicon nitrides, Boron carbides, Plastic properties, Fracture(Mechanics), Microstructure, Wear resistance, Fabrication, Temperature, Single crystals

Subject Categories : Ceramics, Refractories and Glass
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE