Chapter Six - Dynamic constitutive distortional law of materials—micro mechanism based on dislocation dynamics

Abstract

The core problem of what distinguishes the dynamic constitutive distortional law with the quasistatic one is the strain-rate effect, initiating the studies on thermoviscoplastic constitutive equation. In the previous chapter, this problem was discussed from the view of macroscopic mechanics, while in this chapter, its microscopic physical foundation will be correspondingly discussed from the view of dislocation dynamics. Based on the thermally activated mechanism of dislocation dynamics, different types of thermoviscoplastic constitutive equation are substantially attributed to different thermoactivated potential barrier shapes. The classical Seeger's model corresponds to the simplest linear potential barrier shape. All other advanced models correspond to different nonlinear potential barrier shapes, mainly including the Davidson–Lindholm model, the Kocks–Argon–Ashby model, the Wang's hyperbolic barriers spectrum model, the Zerilli–Armstrong model, and the mechanical threshold stress model, which are successively discussed in this chapter.