6370 DE ARELLANO.LOPEZ et aL.: CREEP OF SIC-WHISKER-REINFORCED ALUMINA 13E5 1400° ORNL20 ● Compression ○4 pt-Bending 75E6 25E6 00E+01 O (MPa) Fig. 10. Linear-linear plot of the creep rates obtained on ORNL20 by compression(filled symbols) and nt bending (open symbols, Lin et al. [10). The critical stress appears to be independent of ARCO30 were considered to correspond to the tivity of the diffusivities in AlO3 to impurities is ame diffusional kinetics, although ArCO deforms very high. It was concluded, however, that the rate- by gBs and the composites by PD. In a previous controlling diffusion in the monolith was Al publication [13]. details were discussed of the through the grain boundaries, and that this fact diffusion kinetics, which is complex as the sensi- was essentially unchanged in the composites with ARCO6 1500°C 2.0E5 1400° G-21 MPa 50E6 a~38M"Pa1300 00E+0 o(MPa) Fig. ll. Linear-linear plot of the creep rates of ARCO6 composites [6] showing the dependence of the threshold stress with the temperature. As seen, Go decreases as T increases.ARCO30 were considered to correspond to the same di€usional kinetics, although ARCO0 deforms by GBS and the composites by PD. In a previous publication [13], details were discussed of the di€usion kinetics, which is complex as the sensi￾tivity of the di€usivities in Al2O3 to impurities is very high. It was concluded, however, that the rate￾controlling di€usion in the monolith was Al3+ through the grain boundaries, and that this fact was essentially unchanged in the composites with Fig. 10. Linear±linear plot of the creep rates obtained on ORNL20 by compression (®lled symbols) and by four-point bending (open symbols, Lin et al. [10]). The critical stress appears to be independent of the testing technique. Fig. 11. Linear±linear plot of the creep rates of ARCO6 composites [6] showing the dependence of the threshold stress with the temperature. As seen, s0 decreases as T increases. 6370 DE ARELLANO-LO PEZ et al.: CREEP OF SiC-WHISKER-REINFORCED ALUMINA