Analytic model of the remobilization of pinned glide dislocations: including dislocation drag from phonon wind

TL;DR

This paper develops an analytic model for dislocation remobilization considering variable drag effects from phonon wind, highlighting its significance at high temperatures and strain rates, and discussing the implications of dislocation velocity limits.

Contribution

It introduces a refined analytic model incorporating temperature and pressure-dependent dislocation drag, including phonon wind effects, for high strain rate regimes.

Findings

Dislocation drag remains dominant at high temperatures and intermediate strain rates.

The model predicts a limiting dislocation velocity influenced by phonon wind effects.

Debates on supersonic dislocations are discussed in relation to the velocity limit.

Abstract

In this paper we discuss the effect of a non-constant dislocation drag coefficient on the very high strain rate regime within an analytic model describing mobile-immobile dislocation intersections applicable to polycrystals. Based on previous work on dislocation drag, we estimate its temperature and pressure dependence and its effects on stress-strain rate relations. In the high temperature regime, we show that drag can remain the dominating effect even down to intermediate strain rates. We also discuss the consequences of having a limiting dislocation velocity, a feature which is typically predicted by analytic models of dislocation drag, but which is somewhat under debate because a number of MD simulations predict supersonic dislocations.