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Comparison of High‐Temperature Crack Growth in SiC‐Whisker‐Reinforced Mullite and Si 3 N 4
Author(s) -
Ritter John E.,
Jakus Karl,
Godin Micheal H.,
Ruh Robert
Publication year - 1992
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.1151-2916.1992.tb07194.x
Subject(s) - mullite , creep , materials science , whisker , composite material , indentation , silicon nitride , nucleation , composite number , nitride , strain rate , growth rate , ceramic , layer (electronics) , geometry , chemistry , organic chemistry , mathematics
Crack growth behavior under creep conditions was studied in SiC‐whisker‐reinforced mullite and silicon nitride. Tests of four‐point bend specimens with indentation cracks were periodically interrupted to observe the creep behavior. At each interruption the bulk creep strain of the specimen, the growth of the indentation cracks, and the nucleation and growth of creep‐induced cracks were measured. A strong linear correlation was observed in both materials between the crack growth rate and the creep strain rate. For a given strain rate, cracks in the silicon nitride composite propagated at velocities about an order of magnitude greater than those in the mullite composite. On the other hand, for similar nominal stresses, creep rates in the silicon nitride composites were about an order of magnitude less than with the mullite composite.