Deformation Behavior of the AMg6 Alloy under the Influence of Pulsed Current of Different Duty Cycle

Abstract

The paper compares the deformation behavior under different tensile conditions (without current; accompanied by pulsed current of different density and duty cycle; when heated by an external source) of the structure and mechanical properties of coarse–grained AMg6 alloy. It is shown that a low duty cycle (Q = 10) of the pulsed current contributes to both an increase and a decrease in flow stresses, depending on the current density used, while a high duty cycle (Q = 20.000) has practically no effect on the deformation behavior. Reducing the current density and duty cycle to minimum values suppresses the Portevin – Le Chatelier effect and contributes to an increase in the strength and relative elongation of the alloy with a negligible thermal effect of the current. Tensioning with an external heat source to temperatures corresponding to the low duty cycle and increased current density pulse current mode results in maximum strength and relative elongation to failure. EBSD analysis showed that the pulsed current contributes to the preservation of a high proportion of large–angle grain boundaries and low dislocation density compared to tensile heating.