The Effect of Particle Migration on the Creep-Rate of Nanocomposites
The tensile creep behaviour of a mullite-SiC nanocomposite containing 5 vol% of SiC particles deformed under stresses from 4 to 50 MPa at 1400 °C has been studied. After grain-size effects had been accounted for, the creep-rate of the nanocomposite was found to be approximately 30× less than that of the monolithic mullite. It is suggested that this reduction is caused not by a threshold stress but by the extra work required to drive diffusion in the low diffusivity SiC particles so that they can move with the grain boundaries during creep. A model is presented which predicts the rate of creep under these conditions and gives reasonable agreement with the experiments at low stresses.
T. Ohji, T. Sekino and K. Niihara
J.E. Pitchford et al., "The Effect of Particle Migration on the Creep-Rate of Nanocomposites", Key Engineering Materials, Vols. 317-318, pp. 445-448, 2006