Results of an International Round-Robin for Tensile Creep Rupture of Silicon Nitride
William E. Luecke
Fourteen laboratories participated in an ubterkabiratirt study to establish the within- and between-laboratory repeatability of tensile creep rupture of silicon nitride. In air at 1375 C at 200 Mpa the times to failure ranged over a factor of 50, and the minimum creep rates ranged over a factor of 20. Despite these large ranges, taken individually, no one laboratory stands out from any other, all produced equally acceptable data. Consumers of silicon nitride tensile creep data must accept this magnitude of variability in reported creep data. The wide variety of specimen shapes and sizes, gripping systems, extensometry techniques, and temperature measurement strategies make it impossible to assign definitively the root cause of the variability. However, there was a significant specimen size effect. As a group, the small-diameter specimens lasted roughly five times longer and crept three times more slowly than the large diameter usa-buttonhead specimens. A possible interpretation of the origin of this difference is that the oxidizing conditions affect more of the volume of the small specimens during the test.
Results of an International Round-Robin for Tensile Creep Rupture of Silicon Nitride, Journal of the American Ceramic Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850437
(Accessed February 23, 2024)