Portevin-Le Chatelier Characterization of Quenched Al-Mg Alloy Sheet with Different Mg Concentrations

In the present study, the PLC characteristic parameters and DSA mechanism of Al-(2.86 similar to 9.41) Mg alloy sheets were investigated during tensile testing at room temperature with a tensile rate of 1 x 10(-3) s(-1). On the basis of the solution Mg concentrations in the alpha-Al matrix, the initial vacancy concentration, the second-phase particle configuration and the recrystallized grain configuration are almost the same by quenching treatment. The results show that the type of room-temperature tensile stress-strain curves of quenched Al-(2.86 similar to 9.41) Mg alloy sheets varied according to the Mg content. The type of stress-strain curve of the Al-2.86 Mg alloy sheet was B + C, while the type of stress-strain curve of the Al-(4.23 similar to 9.41) Mg alloy sheets was C. When the quenched Al-(2.86 similar to 9.41) Mg alloy sheets were stretched at room temperature, the strain cycle of the rectangular waves corresponding to the high stress flow Delta epsilon(max)(T) and stress drop amplitude Delta sigma on the zigzag stress-strain curve of alloy sheets increased with increasing the Mg content. Moreover, the strain cycle of Delta epsilon(max)(T) and Delta sigma on the stress-strain curve of alloy sheets increased gradually with increasing tensile deformation. The yield stress of quenched Al-(2.86 similar to 9.41) Mg alloy sheets increased gradually with increasing the Mg content. Moreover, the critical strain corresponding to yield stress epsilon(sigma) and the critical strain corresponding to the occurrence of the PLC shearing band epsilon(c) of alloy sheets both increased with increasing the Mg content. However, the difference in flow strain value Delta epsilon(c-sigma) between epsilon(c) and epsilon(sigma) of alloy sheets decreased gradually with increasing the Mg content.