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-(2.86~9.41) Mg alloy sheets were investigated during tensile testing at room temperature with a tensile rate of 1 × 10(−3) s(−1). On the basis of the solution Mg concentrations in the α-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-(2.86~9.41) 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-(4.23~9.41) Mg alloy sheets was C. When the quenched Al-(2.86~9.41) Mg alloy sheets were stretched at room temperature, the strain cycle of the rectangular waves corresponding to the high stress flow [Formula: see text] and stress drop amplitude [Formula: see text] on the zigzag stress–strain curve of alloy sheets increased with increasing the Mg content. Moreover, the strain cycle of [Formula: see text] and [Formula: see text] on the stress–strain curve of alloy sheets increased gradually with increasing tensile deformation. The yield stress of quenched Al-(2.86~9.41) Mg alloy sheets increased gradually with increasing the Mg content. Moreover, the critical strain corresponding to yield stress [Formula: see text] and the critical strain corresponding to the occurrence of the PLC shearing band [Formula: see text] of alloy sheets both increased with increasing the Mg content. However, the difference in flow strain value [Formula: see text] between [Formula: see text] and [Formula: see text] of alloy sheets decreased gradually with increasing the Mg content.