Abstract
Four types of aluminum bicrystals having a longitudinal twist boundary parallel to the {111} plane and with a misfit angle of about 0.38 rad (22°) were grown by a modified Bridgman method. The fatigue tests were done on a bending fatigue testing machine and carried out at a constant strain amplitude of about 0.2% and cyclic frequencies of 30.4 Hz.
It has been found that fatigue cracks are initiated along the crystal boundaries. The initiation of the fatigue cracks along the crystal boundaries is due to the operation of the secondary slip systems whose slip planes are parallel to the crystal boundary one.
