莫来石陶瓷的室温应力腐蚀开裂行为

Room-Temperature Stress Corrosion Cracking in Mullite Ceramic

分别在空气、蒸馏水和碱性溶液中测定了莫来石陶瓷材料在不同外加应力水平下的室温断裂寿命，探讨了应力腐蚀裂纹缓慢扩展机理．研究表明，在高载荷下，吸附效应为裂纹扩展的主导机理，而在低载荷下，裂纹尖端钝化效应为主导机理．此外，在蒸馏水和碱性溶液两种介质中裂纹扩展指数N值有所不同，反映了介质对水合层的不同溶解能力．

The time-to-failure of mullite ceramics was meajsured as a function of applied stress in air,distilled water and alkaline solution at room temperature, respectively, and the mechanism of stress corrosion cracking was discussed. It is shown that absorption effect is the dominant mechanism at high stress level, while blunting effect is dominant at low stress level. In addition, crack growth parameters in the alkaline solution are different from that in water, which implies that the two media hague different solvability on the hydrate laper.