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The fracture toughness and subcritical crack growth behaviour of both SiC-whisker reinforced and monolithic silicon nitride ceramics are measured at several temperatures up to 1400 C in air. At all testing temperatures, the K(IC) values of the composite are larger than those of the monolithic material. This is attributed to crack deflection by the SiC-whiskers. The K(I)-V diagrams of the composite are displaced to higher K(I) ranges compared with those of the monolithic material, but their crack growth rate exponents n are almost identical at each of the testing temperatures. At room temperature, cyclic loading increases the subcritical crack growth rate relative to static loading in the composite material. This phenomenon is reported in monolithic silicon nitride ceramics. From the above mentioned findings, it is concluded that the basic fatigue properties are not changed by the dispersion of SiC-whiskers.

Additional information

Authors: YAMAUCHI Y, JRC Petten (NL);STEEN M, JRC Petten (NL);BRESSERS J, JRC Petten (NL)
Bibliographic Reference: Paper presented: 4th International Conference on Creep and Fracture of Engineering Materials and Structures, Swansea (GB), April 1-6, 1990
Availability: Available from (1) as Paper EN 35156 ORA
Record Number: 199010596 / Last updated on: 1994-12-01
Original language: en
Available languages: en