A Description of Tensile Stress-Strain Curve Based on the Random Barriers Theory

Abstract

A new approach to describe the time-independent tensile stress-strain curve is presented by means of the concept of the field of resisting force against the movement of dislocations. The cyclic plasticity model proposed in the previous paper based on this concept indicates that a stress-strain relation in the steady state can be expressed by three internal state variables concerned with such field and microscopic structures. In this paper, a tensile stress-strain relation with different type of yielding can be described by reflecting the microscopic behaviors such as the catastrophic increase of movable dislocation density at the early stage of plastic deformation in the change of one of these three variables. This description has provided satisfactory agreement with each experimental curve for carbon steel and brass with a wide range of strain.