Impact fatigue of an alumina ceramic

A new type of pendulum impact apparatus is described for determining single and repeated impact strength of ceramics, It has been demonstrated that specimens of a Sintox alumina ceramic exhibit fatigue behaviour, having a high stress plateau followed by progressively increasing endurance with decrease in applied impact energy. A fatigue limit, at least from the engineering view point, has been drawn at high endurances (10⁵ impacts). The influence of environment (static fatigue) and/or plastic deformation to explain the fatigue behaviour is suggested.