6362 E ARELLANO. LOPEZ et aL. CREEP OF SIC-WHISKER-REINFORCED ALUMINA accommodated grain-boundary sliding (GBS) kinetics are unchanged from GBs to PD. mechanism [16-18]. In whisker-reinforced alumina, expected, models predict that the creep rates are the whiskers impede sliding of the grain boundaries, about one order of magnitude faster if deformation so that deformation is controlled by pure diffu- proceeds via GBs compared to PD [19. For both sional(PD)creep, thus explaining partially the GBs and PD, the strain rate is controlled by the observed reduction in creep rates [13]. If diffusion diffusion of the slowest of the species along the 1400°c cp eoo oo ◇口o 1E8 O ( MPa 1400°c ◇ 口 △ ①◇ OORNL10 口ANL15 O (MPa) Fig. 1. Strain rate of the composites, ie, corrected by the nominal grain size of the matrix, d, vs stress for samples containing (a)less than 7 vol. of whiskers, and(b) more than 7 vol. of whiskers. The grain-size exponent was taken as p= 3 for all cases.accommodated grain-boundary sliding (GBS) mechanism [16±18]. In whisker-reinforced alumina, the whiskers impede sliding of the grain boundaries, so that deformation is controlled by pure di€u￾sional (PD) creep, thus explaining partially the observed reduction in creep rates [13]. If di€usion kinetics are unchanged from GBS to PD, as expected, models predict that the creep rates are about one order of magnitude faster if deformation proceeds via GBS compared to PD [19]. For both GBS and PD, the strain rate is controlled by the di€usion of the slowest of the species along the Fig. 1. Strain rate of the composites, e_c, corrected by the nominal grain size of the matrix, d, vs stress, for samples containing (a) less than 7 vol.% of whiskers, and (b) more than 7 vol.% of whiskers. The grain-size exponent was taken as p = 3 for all cases. 6362 DE ARELLANO-LO PEZ et al.: CREEP OF SiC-WHISKER-REINFORCED ALUMINA