The dynamics of Portevin-Le Chatelier bands in an Al-Mg alloy from infrared thermography

The dynamics of the Portevin-Le Chatelier (PLC) bands in an Al-3.2% Mg alloy loaded in tension at constant strain rate is investigated through temperature field measurements from infrared thermography. In addition to allowing the determination of most band characteristics, the temperature field provides insights into the dynamics of band formation and motion. For type B bands at low strain rate, band hopping is quasi-isothermal, whereas band formmation and propagation are found to be quasi-adiabatic in type A bands at large strain rate. Furthermore, band formation is more progressive, the bandwidth is larger and jumps in stress and local strain rate are smaller in type A than in type B. Consequences of this modulation of localization features on the dynamical regime of PLC bands are discussed in terms of the so-called dynamization of the characteristic stress Versus strain rate curves. (C) 2007 Elsevier B.V. All rights reserved.