Stress dependence of the creep behavior of silicon carbide whisker-reinforced alumina

Technical Report · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6785530

Donaldson, K Y; Venkateswaran, A; Hasselman, D P

Creep tests of Silicon carbide-whicker reinforced alumina at 1500 C yielded creep strain vs. time curves exhibiting typical primary, secondary and tertiary creep. The initial creep rate, which is proportional to the matrix creep rate, exhibited a stress exponent of 1.59, typical for single-phase polycrystalline alumina, while the apparent stress exponent for secondary (steady-state) creep was 2.88. The presence of the whiskers appeared to suppress cavitation or other damage, thereby eliminating any contribution from elastic creep by crack growth or crack-enhanced creep to creep deformation. Analysis of the creep behavior of short elastic fiber reinforced matrix composite based on the theory of Kelly and Street indicated that stress dependent sliding at the silicon carbide-alumina interface and stress dependent partial whisker fracture, resulting in a decrease in average aspect ratio, could be the mechanisms responsible for the higher apparent stress exponent in the secondary regime.

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA). Dept. of Materials Engineering
• OSTI ID: 6785530
• Report Number(s): AD-A-219347/2/XAB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360203* -- Ceramics
Cermets
& Refractories-- Mechanical Properties
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
ASPECT RATIO
BEHAVIOR
CARBIDES
CARBON COMPOUNDS
CAVITATION
CERAMICS
CHALCOGENIDES
CRACK PROPAGATION
CREEP
CRYSTALS
DEFORMATION
ELASTICITY
INTERFACES
MECHANICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
POLYCRYSTALS
SILICON CARBIDES
SILICON COMPOUNDS
STRESSES
TENSILE PROPERTIES