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Fracture of Polycrystalline MgAl 2 O 4
Author(s) -
STEWART R. L.,
BRADT R. C.
Publication year - 1980
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.1151-2916.1980.tb09847.x
Subject(s) - crystallite , materials science , grain boundary , intergranular corrosion , transgranular fracture , fracture toughness , grain size , intergranular fracture , fracture (geology) , mineralogy , crystallography , composite material , metallurgy , microstructure , chemistry
The fracture toughness of stoichiometric polycrystalline MgAl 2 O 4 was measured as a function of grain size and temperature to 1400°C. The room temperature fracture toughnesses are comparable to reported single‐crystal values. No effect of grain size was detected. Two regions of K I c = f ( T ) were observed, both showing a decreasing K I c with an increasing T . In the low‐temperature region, fracture is of a mixed mode, transgranular and intergranular character. The ∼10 −4 MN/m 3/2 °C ( dK 10 dT ) decrease is governed primarily by dE/dT . The high‐temperature region, T >900°C, has a much larger dK 10 dT decrease, ∼ 10 −3 MN/m 3/2 °C, and a fracture character that is totally intergranular, suggesting dominance by grain‐boundary processes.