In order to determine the degree and type of secondary slip, the full deformation matrix was deduced from instantaneous orientation and shape measurements at successive strain intervals for crystals of various orientation, deformed in tension at room temperature. It was found that the data for various orientations within the standard triangle were very similar, and represented a combination of the responses to internal stresses and applied stresses. The internal stress due to primary edge dislocations was relieved by the same combination of secondary shears in all orientations; 2 particular Lomer-Cottrell reactions, plus a shear on the cross-glide plane giving zero residual stress. Analogous sets of shears occurred to relieve the internal stresses, which arose from conjugate glide after overshoot ended, and co-planar glide in orientations close to [111]-[110]. This type of slip, which was not visible at the surface, was termed microscopic secondary slip. Deviations from this microscopic secondary glide were always in the direction of the applied stress. Except in the special case of positive and negative cross-slip, secondary slip lines visible at the surface represented the slip which occurred in response to an applied stress.

Quantitative Determination of Secondary Slip in Copper Single Crystals Deformed in Tension. Z.S.Basinski, S.J.Basinski: Philosophical Magazine, 2004, 84[3], 213-51