The plastic deformation of bcc 3He crystals has been studied near the melting curve, in the temperature range 0.65 K ≤T≤.17 K, and for strain rates, ɛ˙, from 2x10-6 to 2x10-4 sec-1. The resulting relations between strain rate and stress, at a given temperature, are accounted for in terms of dislocation climb and vacancy diffusion in the solid He. The temperature dependence of the strain rate at a given stress indicates that a nonclassical mechanism underlies the deformation process. The vacancy diffusion coefficient in bcc 3He, as a function of temperature, is deduced from these results, and an energy bandwidth for delocalized vacancies of 0.24±0.05 K is obtained through a fit to theoretical predictions.
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