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Creep and Creep‐Recovery Behavior in Silicon‐Carbide‐Particle‐Reinforced Alumina
Author(s) -
Deng ZhenYan,
Shi JianLin,
Zhang YuFeng,
Lai TingRong,
Guo JingKun
Publication year - 1999
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.1151-2916.1999.tb01858.x
Subject(s) - creep , materials science , composite material , equiaxed crystals , silicon carbide , particle (ecology) , carbide , grain boundary , microstructure , metallurgy , oceanography , geology
Flexure creep and creep‐recovery behavior were investigated for monolithic Al 2 O 3 and 10‐vol%‐SiC‐particle‐reinforced Al 2 O 3 ‐matrix composites in an air atmosphere at temperatures of 1160°‐1400°C. Two types of SiC particles were used: one has an average size of 2.7 µm and has an amount of SiO 2 impurities per unit surface area that is one order of magnitude higher than the other, which has an average size of 0.6 µm. Compared to the creep behavior of monolithic Al 2 O 3 , the strain rate of the composites with the 0.6 µm SiC particles (denoted here as S‐10) did not decrease; the composites with the 2.7 µm SiC particles (denoted here as L‐10) exhibited excellent creep resistance. This difference was related to the microstructural features and the oxidation behavior of the composites: the Al 2 O 3 grains in S‐10 were mainly equiaxed, only ∼10% of the Al 2 O 3 grains were elongated, and most of the SiC particles that resided at the grain boundaries or at triple‐grain junctions were oxidized during creep, whereas the Al 2 O 3 grains in L‐10 were mostly irregularly shaped and elongated and most of the SiC particles were entrapped in the Al 2 O 3 matrix grains, which prevented the oxidation of the SiC particles. These different microstructural features were associated with different amounts of SiO 2 impurity content per unit surface area on the SiC particle surfaces. In addition, the monolithic Al 2 O 3 showed no anelastic recovery when the load was removed; however, the composites exhibited significant anelastic recovery, especially for L‐10. This phenomenon was attributed to the elongated grain morphology.