The indentation-quench method for investigating surface crack propagation has been studied through both experiments and model. The influential factors for surface crack propagation such as specimen thickness, thermal fatigue property, and quench temperature difference (ΔT) and one single specimen being used throughout a whole test ΔTwere surveyed in this paper. Practical results were obtained for ZrB2-20%SiC-10%AlN (ZSA) ultra-high temperature ceramic. The percentage crack growth versus ΔTcurves showed stable crack growth in a relative low ΔTinterval and unstable crack growth above a certain ΔT, and these regimes were sensitive to the thickness. The total stress intensity factor (KI) combining residual stress and thermal stress considering dynamical behavior during the quenching test was calculated by a surface crack theoretical model, the result of calculation was analyzed influential factors and crack propagation .
Stable Crack Growth of Surface Crack across the Fusion Line.