Influence of Ag and processing routes on the Portevin-Le Châtelier behavior of Al-Mg based alloys

This study investigates the influence of Ag and processing routes on the evolution of Portevin-Le Châtelier (PLC) behavior of 5xxx aluminum alloys . Results indicate that the modified alloy, enhanced with the alloying element Ag, can suppress the serrated yielding behavior and increase the strength by approximately 80 MPa during aging treatment. Ag atoms promote stable Mg-Ag cluster and reduce solute Mg atoms in the matrix, which weakens the pinning effect on dislocations. Furthermore, compared to the T6 process, the critical strain of the T8 process alloy reaches a maximum of about 12 %. The serrated flow propagation characteristics gradually transition from continuous propagation to a combination of continuous and spatial jumping propagation. This behavior results from pre-deformation prior to aging, which facilitates the formation of additional substructures and forest dislocations that are uniformly distributed during the subsequent aging recovery process. • Ag-addition suppress the Portevin-Le Châtelier behavior. • Pre-deformation changes the type of serrated flow deformation bands. • Pre-deformation alloy presents better work hardening rate and critical strain.