Work Hardening and Dislocation Arrangement of fcc Single Crystals. I. Plastic Deformation and Slip Line Studies of Nickel Single Crystals

The work hardening of nickel single crystals and its temperature dependence are investigated. The results are discussed in terms of the long-range stress theory of work hardening. From an analysis of the temperature dependence of the stress τIII at the onset of stage III, we deduce the stacking fault energy of nickel and the magnitude of the stress concentrations in the deformed crystals. Particular attention is given to the question: Which of the hardening parameters are structure sensitive and which are insensitive to the differences in the microstructure of the crystals? Simultaneous determinations of the length and height of individual slip lines are carried out. They check with the information on the stress concentrations and agree well with the predictions of the work-hardening theory.