Chairman, University of Pennsylvania, Philadelphia, Pa.
Senior research scientist, Aeronautical Research Laboratory, Melbourne,
Student, Amherst College, Amherst, Mass.
de la Veaux, R
SupervisorMember of ASTM, Mechanical Testing Laboratory, University of Pennsylvania, Philadelphia, Pa.
A conflict exists as to whether the saturated flow stress of a wavy slip metal cycled at high plastic strain amplitudes depends on history or not. To resolve this, mechanical tests have been carried out on heavily cold-worked copper and the structures studied by transmission electron microscopy. It has been found that, for any material, there exists a prestrain (dependent on many testing and material factors) below which cyclic stress-strain response is history independent and above which it is dependent. For severe prestrains, the cycling is insufficient to balance the dislocation structures in the cell walls, and the cells are more angular and misoriented than those which occur in annealed metal subjected to strain cycling.
Paper ID: JTE11699J