Experimental investigation and modeling of the creep behavior of ceramic fiber-reinforced SiO2 aerogel

Ambient creep tests at constant stresses of 0.05 and 0.1 MPa were conducted on a ceramic fiber-reinforced SiO2 aerogel for more than 240 h. Experimental result shows that there are creep deformations even at very low stress level, and the creep strains finally reach constant values. High temperature creep experiments were also investigated at constant stresses of 0.05 and 0.2 MPa for 1800 s. The creep strains in 1800 s at 900 degrees C are 20-69 times higher than that at 300 degrees C. The creep behavior could be well described by the power-law creep model. Scanning Electron Microscope (SEM) analysis was also conducted to understand the micro mechanism of the creep behavior. Thermal softening of aerogel nanoparticles to generate larger ones was found to be the main reason for the change in mechanical properties at high temperature. (C) 2011 Elsevier B.V. All rights reserved.