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Effect of Delamination on the Transverse Thermal Conductivity of a SiC‐Fiber‐Reinforced SiC‐Matrix Composite
Author(s) -
Donaldson Kimberly Y.,
Trandell Barbara D.,
Lu Yangsheng,
Hasselman D. P. H.,
Maurer Norb
Publication year - 1998
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.1151-2916.1998.tb02520.x
Subject(s) - materials science , thermal conductivity , composite material , delamination (geology) , thermal conduction , composite number , transverse plane , conductivity , fiber pull out , composite laminates , chemistry , structural engineering , engineering , paleontology , biology , subduction , tectonics
The effect of delamination on the transverse thermal conductivity of a biaxial multiweave SiC‐fiber‐reinforced chemical‐vapor‐infiltrated‐matrix composite was studied. The delamination process, induced by compressive loading, consisted of enlarging and widening pre‐existing interply cavities in the as‐received composite. Ultrasonic scanning suggested that the delamination process resulted in mechanical debonding between the plies. At room temperature, the delamination reduced the transverse thermal conductivity by a factor of ∼5. As a result of gaseous conduction in the interply cavities and/or delamination, the thermal conductivity was higher in air/nitrogen at atmospheric pressure than under vacuum, a difference that was especially pronounced in the delaminated sample. The thermal conductivity of the as‐received and delaminated samples exhibited a negative and positive temperature dependence, respectively, which resulted in almost‐equal values at temperatures >1000°C. Data analysis showed that the thermal conductivity of the delaminated composite was almost independent of the thermal conductivity of the plies themselves; instead, the thermal conductivity of the composite was controlled primarily by conduction across the delaminations at areas of direct contact, conduction through the gaseous phase within the delaminations, and radiation across the delaminations.