Deformation of molybdenum single crystals at slow rates of strain

Abstract

Molybdenum single crystals were deformed in tension, and the relationship between stress, strain, and strain rate was studied in the pre‐yield region. The high work‐hardening rate of the pre‐yield deformation is explained in terms of the exhaustion of mobile edge dislocation segments. The rate of exhaustion, ∂ log ϱ/∂ϵ, is of the order of 10³ to 10⁴. The temperature and strain rate dependence of the stress required to deform the crystals at strain rates < 10⁻⁷ s⁻¹ was investigated at strains > 0.01. The activation energy and activation volume have values between 2 and 4 eV, and between 50 and 100 b³ respectively. This result suggests that the mechanism of overcoming the Peierls friction is not rate controlling at the slow rates of strain. Alternative interpretations are discussed.