The Behavior of Graphite Under Alternating Stress

The fatigue properties of grade AUF extruded polycrystalline graphite were investigated at ambient and elevated temperatures. Specimens cut parallel to the axis of extrusion were stressed in reversed bending at room temperature and at 3550 F. The endurance limit of this graphite was found to increase from 2500 psi at room temperature to about 4400 psi at 3550 F. The increase in endurance limit is correlative with the increase in short-time tensile strength with temperature observed in earlier studies of graphite.