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Creep Deformation in an Alumina–Silicon Carbide Composite Produced via a Directed Metal Oxidation Process
Author(s) -
Lin HuaTay,
Breder Kristin
Publication year - 1996
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1996.tb08965.x
Subject(s) - materials science , creep , composite number , composite material , grain boundary , silicon carbide , grain size , cavitation , carbide , grain boundary sliding , stress (linguistics) , alloy , metallurgy , microstructure , linguistics , physics , philosophy , mechanics
Flexural creep studies were conducted in a commercially available alumina matrix composite reinforced with SiC particulates (SiC p ) and aluminum metal at temperatures from 1200° to 1300°C under selected stress levels in air. The alumina composite (5 to 10 μm alumina grain size) containing 48 vol% SiC particulates and 13 vol% aluminum alloy was fabricated via a directed metal oxidation process (DIMOX(tm))† and had an external 15 μm oxide coating. Creep results indicated that the DIMOX Al 2 O 3 –SiC p composite exhibited creep rates that were comparable to alumina composites reinforced with 10 vol% (8 (μm grain size) and 50 vol% (1.5 μm grain size) SiC whiskers under the employed test conditions. The DIMOX Al 2 O 3 –SiC p composite exhibited a stress exponent of 2 at 1200°C and a higher exponent value (2.6) at ≥ 1260°C, which is associated with the enhanced creep cavitation. The creep mechanism in the DIMOX alumina composite was attributed to grain boundary sliding accommodated by diffusional processes. Creep damage observed in the DIMOX Al 2 O 3 ‐SiC p composite resulted from the cavitation at alumina two‐grain facets and multiple‐grain junctions where aluminum alloy was present.