Plastic flow localization processes and their schematization during testing of flat aluminum-magnesium alloy specimens
An experimental technique for studying the mechanical behavior and plastic deformation in the conditions of space-time inhomogeneity has been proposed based on the digital image correlation method and a contactless three-dimensional digital optical system Vic-3D. Analysis results are reported for the evolution of inhomogeneous strain and local strain rate fields in AMg2m aluminum-magnesium alloy specimens subjected to uniaxial tension with a constant rate of kinematic loading. The effect of quasi-periodic strain field homogenization during intermittent plastic deformation has been revealed. This effect consists in that the stages of the appearance of local zones of active plastic flow in the material (initiation and propagation of deformation bands) alternate with the stages of macroscopic strain equalization over the specimen. The parameters (height and width of the deformation band front, deformation band velocity, coefficient of plastic deformation inhomogeneity) characterizing the macroscopic plastic flow localization are analyzed. A series of mechanical tests were conducted to evaluate the influence of specimen geometry and loading rate on these parameters.