Strain rate sensitivity of flow stress under superimposition of ultrasonic oscillatory stress during plastic deformation of RbCl doped with Br~- or I~-

摘要

Strain rate cycling tests were carried out under superimposition of ultrasonic oscillation during plastic deformation of RbCl single crystals doped with Br~- or I~-. The relation between the strain rate sensitivity λ (= dτ/d ln ε) of flow stress and stress decrement Δτ due to application of oscillation has a stair-like shape and is divided into three regions, two plateaus at low and high Δτ and the decreasing λ region between them. The stress decrement τ_p at the first bending point is considered to be the effective stress due to an impurity and the value of λ_p, the difference in λ between the first and second plateau regions is also a part of λ due to an impurity. Values of τ_p and λ_p were measured from 77 K to room temperature. Assuming the Cottrell-Bilby relation for RbCl crystals doped with Br~- or I~-. The interaction energies between dislocation and Br~- or I~- were determined to be 0.50 or 0.58 eV in RbCl, respectively.