Kinetic Research of Oxidation Induced Crack Healing of Engineering Ceramics (II) Model Testing: The Kinetic Research of Al_2O_3-TiC_p Composite

Oxidation reaction happened when Al2O3-TiCp composite heated at high temperature. The reaction producer moved to the crack area which induced crack healing. The heating temperature, time, and indentation affected the crack healing greatly. The kinetic analysis of crack healing of Al2O3-TiCp composite shows that: the strength recovery can be expressed by the following formula:σf/σf0=[1-2△Pk~(1/2)/B0·t1/2]-1/4, and the velocity of crack healing can be showed as:-(?)CV/(?)t=c2V0·△P/B0CV·1/2(k/t)~(1/2) Reaction velocity constant, reaction time, the rate of volume increases due to reaction, and original crack size are four key factors of crack healing. The analysis of strength before and after crack healing proves the correctness of the crack-healing model.