INTERGRANULAR CRACKING IN ALUMINUM-ALLOYS

Intergranular cracking of aluminum alloys occurs by a variety of proce sses in a host of structural components. Cracks emanate from holes and corners of support structures and heterogeneously spread along grain boundaries. In the present study, cracked specimens were investigated using local orientation measurement techniques. True representation of grain boundaries in spaces of five or eight dimensions was emphasized in characterizing the microstructure. Orientation of the grain bounda ry plane with respect to the stress axis and with respect to the cryst al lattice was found to play an important role in determining GB ''spe cialness'' in addition to misorientation of the crystallite lattices.