Molecular Dynamics Simulation of Portevin-Le Chatelier Effect in Al-Mg Alloys: Effects of Solute Concentration, Temperature, and Tensile Rate

The interaction between dislocation and solute atoms during uniaxial tensile-loading deformation was simulated based on molecular dynamics. It is proved from the microscopic view (atomic level) that the essence of Portevin-Le Chatelier (PLC) effect originates from the influence of the solute atmosphere on the dislocation motion. The formation of the solute atmosphere is caused by lattice distortion. The lattice distortion increases the energy of the system, which promote the spontaneous diffusion of solute atoms through vacancies to the vicinity of edge dislocations to reduce the energy of the system. The simulation results show that higher solute atom concentration, lower strain rate, and temperature make the PLC effect more significant.