The effect of residual stress on whisker reinforcements in SiCw-Al2O3 composites during cooling

The effect of residual stress on whisker reinforcements in SiCw-Al2O3 composites from 293 K to 77 K was investigated. The fracture toughness of SiCw-Al2O3 composites measured at 77 K was ∼26% higher than that at 293 K. The calculated compressive stress of SiC whiskers at 77 K was ∼600 MPa, and the local stress distribution is demonstrated by in-situ Raman spectra and fluorescence spectra. R-Curve behaviors and crack opening displacement profiles were determined to compare the effect of residual stress on crack bridging at different temperatures. The experimental results verified that crack bridging was enhanced by residual stress at 77 K, which made the SiCw-Al2O3 composite to be a promising material for cryogenic applications.