Constitutive Relation for Rate-Dependent Plastic Flow in Polycrystalline Metals
- 1 April 1969
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 40 (5), 2287-2293
- https://doi.org/10.1063/1.1657974
Abstract
The rate‐dependent constitutive relation developed by Taylor, which considers dislocation motion only in glide directions and on glide planes for which the shear stress is maximum, is extended to include dislocation motion in all glide directions on all glide planes. The theory requires that grain orientation be random, that expanding dislocation loops be rectangular, and that the velocity of edge dislocations be much greater than the velocity of screw dislocations. The velocity of screw dislocations is assumed to be given by vs=vm exp (‐B/τ), where τ is the applied shear stress, B is a constant, and vm is the elastic shear wave velocity. On the basis of this theory, elastic wave attenuation in Armco iron is calculated and compared with the experimental data of Taylor and Rice. It is found that the mobile dislocation density necessary for the theoretical calculation to agree with experimental data is five times greater than that obtained by Taylor on the basis of the simpler theory. Likewise, for a given shear stress, it is found that the dislocation velocity is greater than that determined previously. This indicates that the results obtained on the basis of the simpler theory may significantly underestimate the velocity of individual dislocations as well as the mobile dislocation density.Keywords
This publication has 10 references indexed in Scilit:
- The relative velocity of edge and screw dislocationsActa Metallurgica, 1967
- Dislocation Dynamics and Precursor AttenuationJournal of Applied Physics, 1967
- Investigation of Precursor Decay in Iron by the Artificial Viscosity MethodJournal of Applied Physics, 1967
- Yield-Point Phenomenon in Impact-Loaded 1060 AluminumJournal of Applied Physics, 1966
- Dynamical Dislocation Theory of Crystal Plasticity. I. The Yield StressJournal of Applied Physics, 1965
- Dislocation Dynamics and Dynamic YieldingJournal of Applied Physics, 1965
- Elastic-Plastic Properties of IronJournal of Applied Physics, 1963
- Dynamic Yield Behavior of Explosively Loaded Metals Determined by a Quartz Transducer TechniqueJournal of Applied Physics, 1962
- Dislocation Multiplication in Lithium Fluoride CrystalsJournal of Applied Physics, 1960
- Mobility of Edge Dislocations in Silicon-Iron CrystalsJournal of Applied Physics, 1960