Low-temperature plastic flow was investigated by studying the tensile and creep-deformation characteristics. The dependence of the flow stress upon temperature and strain-rate was used to evaluate the thermal activation energy, while the activation area was deduced from stress-change creep experiments. A value of 0.6eV was obtained for the total obstacle energy in both electrolytic and commercial copper. The activation areas of three selected purities fell in the range of 1200 to 100b2. A forest intersection mechanism appeared to control the temperature-dependent part of the flow stress. The increase in the athermal component of the flow stress, with impurity content, was attributed to a change in the dislocation density. The investigation also revealed that thermal activation of some attractive junctions took place during low-temperature creep. The model of attractive junction formation following a stress-decrement during creep, yielded a value of 45mJ/m2 for the stacking-fault energy.

Low-Temperature Deformation Behaviour of Polycrystalline Copper, D.H.Sastry, Y.V.R.K.Prasad, K.I.Vasu: Journal of Materials Science, 1971, 6[12], 1433-40