Accession Number:

ADA235424

Title:

Strength and Microstructure of Ceramics

Descriptive Note:

Technical rept.

Corporate Author:

NATIONAL INST OF STANDARDS AND TECHNOLOGY GAITHERSBURG MD CERAMICS DIV

Personal Author(s):

• Bennison, S. J.
• Chan, H. M.
• Chantikul, P.
• Kelly, J.
• Lathabai, S.

Report Date:

1990-11-01

Pagination or Media Count:

143.0

Abstract:

Results of a program on the toughness properties of monophase ceramics that toughen by bridging are presented. Fracture mechanics models describing this behavior, in the particular context of strength, are developed. Results of strengths tests confirming the essential predictions of the theory are presented. Innovative processing routes suggested by the models are shown to lead to two-phase composites with impressive flaw insensitivity. Titles of appended articles included In situ measurements of bridged crack interfaces in the SEM A loading device for fracture testing of compact tension specimens in the scanning electron microscope Cyclic fatigue from frictional degradation at bridging grains in alumina Role of grain size in the strength an R-curve properties of alumina The role of crystallization of an intergranular glassy phase in determining grain boundary residual stresses in debased aluminas Fabrication of flaw-tolerant aluminum-titanate-reinforced alumina Fundamental condition for existence of microcrack clouds in monophase ceramics.

Descriptors:

• *CERAMIC MATERIALS
• MICROCRACKING
• MICROSTRUCTURE
• DEGRADATION
• PREDICTIONS
• MODELS
• INTERFACES
• PROCESSING
• COMPOSITE MATERIALS
• CRACKS
• ELECTRON MICROSCOPES
• ELECTRONIC SCANNERS
• THEORY
• TOUGHNESS
• GRAIN SIZE
• CRYSTALLIZATION
• FRACTURE(MECHANICS)
• CYCLES
• ALUMINUM OXIDES
• RESIDUAL STRESS
• TENSION
• STRENGTH(GENERAL)
• FATIGUE
• ROUTING
• FRICTION
• TWO PHASE FLOW
• GRAIN BOUNDARIES
• TEST AND EVALUATION
• CLOUDS

Subject Categories:

• Ceramics, Refractories and Glass
• Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE