Analysis of Deformation Kinetics in Seven Body-Centered-Cubic Pure Metals Using a Two-Obstacle Model

Abstract

Published temperature and strain-rate-dependent yield stress data in seven nominally pure bcc metals are analyzed according to a two-obstacle model. A strong intrinsic lattice resistance such as a Peierls barrier and a weaker obstacle representing the collective effects of impurity constituents are combined in a single expression and fit to the individual data sets. Sensitivity of the model fits to selected model parameters is assessed. The activation volume for each obstacle is evaluated and examined to validate the underlying model assumptions. Application of the model demonstrates a consistent Peierls barrier in all seven metals and a reasonable carbon-content dependence in iron of the strength of the impurity obstacle.