Some effects of high rates of strain on the deformation of aluminum single crystals

Specimens of single crystals of commercially pure (99.5 pct) aluminum were prepared in various orientations. The specimens were tested to destruction in an explosively operated impact mechanism. Overall and local strain distributions were measured together with lattice rotation. Some selected specimens were examined under a scanning electron microscope. It was found that while velocity effects are more pronounced in the vicinity of the fracture, the general slip characteristics were largely insensitive to the impact velocity. The lattice rotation, however, showed a considerable dependence on impact velocity. It is proposed here that the difference in the dynamic behavior of edge and screw dislocations in commercially pure aluminum may be the responsible mechanism for the reported anomaly in lattice rotation. Presently on leave at The Pennsylvania State University, University Park, Pa., U.S.A.