Precision measurements of plastic deformation of β‐CuZn at helium temperatures

Abstract By attaching condenser plates directly to the tensile specimen, creep rates of β‐CuZn single crystals have been measured by the capacitance change in the strain‐rate range of 10 −7 to 10 −5 s −1 and at temperatures between 0.7 and 17 K using a 3 He cryostat. Slope of the temperature variation of the stress to give a constant strain‐rate decreases below 5 K and seems to level off at 0 K. The strain‐rate sensitivity becomes almost constant below 2 K. The conventional activation analysis showed that an A RRHENIUS type strain‐rate equation breaks down drastically below 5 K. For an effective temperature T * which gives 2 K at 0 K and asympototically coincides with the testing temperature at 5 K, the experimental results can be fitted to the A RRHENIUS strain‐rate equation with an activation enthalpy Δ H (τ) for the P EIERLS mechanism. The above result is interpreted in terms of the quantum‐mechanical oscillation of the dislocations.

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