Mechanical and environmental factors in the cyclic and static fatigue of a machinable glass-ceramic

The effects of environment on cyclic and static fatigue behaviour were investigated with a machinable glass-ceramic and its original glass. Tests were conducted at ambient temperatures in three environments, i.e. moist air, distilled water and kerosene, and an indentation/bending technique was used. The results indicate that cyclic loading increases crack growth rates of glass-ceramic in all the three environments, but it just has a negligible effect on the original glass. The two materials were very sensitive to the amount of water in the test environment. For static fatigue of the glass-ceramic, both the slopes of da/dt-K-eff curves and their position along the abscissa varied with the environments, but under other conditions, only the position varied. Copyright (C) 1996 Elsevier Science Limited.