Sintering behavior of bi-modal powder compacts
Time dependent sintering of a compact consisting of two regions which sinter at different rates is analyzed. The analysis combines densification with deviatoric creep, since creep serves to relax the stress concentration produced by incompatible densification. The structure of the bi-modal compact is assumed to consist of a sphere of one type of material embedded in a matrix of the other material. Two cases are considered. In one case the matrix, and in the other the sphere, is assumed to sinter faster. The maximum tensile stress generated by incompatible sintering is found to be sensitive to a parameter, ..beta.., which is the ratio of the rate constant for creep, and the rate constant for densification. A large value of ..beta.. reduces the magnitude of the stress. The generation of flaws as a result of this stress is considered. The influence of inhomogeneous sintering on the rate of shrinkage is calculated. The authors find that unless ..beta.. is large the densification rate of the composite will deviate significantly from the simple rule-of-mixtures.
- Research Organization:
- Department of Materials Science and Engineering, Bard Hall, Cornell University, Ithaca, NY
- OSTI ID:
- 6110294
- Journal Information:
- Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 32:7; ISSN AMETA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101* -- Metals & Alloys-- Preparation & Fabrication
CREEP
DEFECTS
DENSITY
DISPERSIONS
FABRICATION
MECHANICAL PROPERTIES
METALLURGY
MIXTURES
PHYSICAL PROPERTIES
POWDER METALLURGY
POWDERS
SHRINKAGE
SINTERING
SPHERES
STRESS INTENSITY FACTORS
TENSILE PROPERTIES
TIME DEPENDENCE