An Interpretation of the Dislocation Velocity‐Stress Exponent

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Abstract
A thermal‐activation model of deformation has been used to analyze the dislocation velocity‐stress exponent, m*, from the relationship v ∝ τ* m* where τ* is the effective stress acting on a mobile dislocation. It is shown that m* is directly related to the retarding‐force profile of the rate‐controlling obstacles to dislocation motion and may be quantitatively evaluated from temperature and strain‐rate sensitivity measurements. Values of the dislocation velocity‐stress exponent reported in the literature, which are based on the applied stress, are shown to be structure sensitive and are not uniquely characteristic of the material.