Premium
The Effect of Microstructure and Microcracking on the Thermal Conductivity of UO 2 ‐U 4 O 9
Author(s) -
BUYKX W. J.
Publication year - 1979
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.1151-2916.1979.tb19070.x
Subject(s) - microstructure , thermal conductivity , materials science , thermal diffusivity , crystallite , laser flash analysis , void (composites) , composite material , mineralogy , grain boundary , thermal , analytical chemistry (journal) , thermodynamics , metallurgy , chemistry , physics , chromatography
Several microstructures were produced in dense polycrystalline UO 2 ‐U 4 O 9 specimens by cooling UO 2+x , solid solutions at different rates. Void formation (intragranular pores, grain‐boundary microcracks) was observed in specimens which had a nonuniform distribution of the U 4 O 9 precipitate; such formation was probably caused by the relief of stresses generated by differential thermal contraction. The microstructures were assessed quantitatively and used to calculate thermal conductivities from theoretical models. The effect of microcracking was calculated. Thermal conductivities were also determined from thermal diffusivity values measured by the laser‐flash method. The thermal conductivity was primarily influenced by the amount of U 4 O 9 , present and the occurrence of voids, whereas the effect of U 4 O 9 , distribution was minor. Good agreement was obtained between theoretical predictions of thermal conductivity based on microstructure and experimental values.