Sr. Choi et Ja. Salem, ULTRA-FAST FRACTURE STRENGTH OF ADVANCED CERAMICS AT ELEVATED-TEMPERATURES, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 242(1-2), 1998, pp. 129-136
An attempt was made to determine elevated-temperature, 'ultra'-fast fr
acture strengths of one alumina, two silicon nitrides and one silicon
carbide by using constant stress-rate ('dynamic fatigue') testing with
a series of 'ultra'-fast test rates. Of the materials rested, the alu
mina exhibited a convergence of strength at stress rates below 3.3 x 1
0(4) MPa s(-1). The strength approached approximately the room-tempera
ture inert strength. By contrast, the silicon nitrides and silicon car
bide did not reveal a strength approach: but exhibited elevated-temper
ature strengths 10 and 20% lower than their respective room-temperatur
e strengths. Although the analytical results imply that the elevated-t
emperature 'inert' strength of a ceramic material can be obtained by u
sing sufficiently high stress rates, the experimental testing rates we
re only sufficient to demonstrate convergence for the alumina. (C) 199
8 Elsevier Science S.A.