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Title: Deformation Mechanisms is a-Phase Silicon Nitride Ceramics

Changes of phase composition and morphology were investigated in Si{sub 3}N{sub 4} both before and after compressive deformation testing. Si{sub 3}N{sub 4} specimens, with 5 wt% Y{sub 2}O{sub 3} and 5 wt% MgAl{sub 2}O{sub 4} additives, were rapidly consolidated to preserve the initial, metastable {alpha}-phase present in the Si{sub 3}N{sub 4} starting powders. Constant strain rate compression tests were used to evaluate the strain rate dependency of the flow stress. At 1723 K, a flow stress dependency value of n = 2 was observed.
Authors:
;
Publication Date:
OSTI Identifier:
5987
Report Number(s):
SAND99-8408C
TRN: AH200115%%354
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 12 Aug 1998
Research Org:
Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ADDITIVES; CERAMICS; COMPRESSION; DEFORMATION; FLOW STRESS; MORPHOLOGY; SILICON NITRIDES; STRAIN RATE; TESTING