Evaluating Characteristics of Deformable Metal via Acoustic Method

The patterns of macroscopically localized plastic flow in polycrystalline aluminum were investigated under uniaxial tensile testing at room temperature. The double-exposure speckle photography was used to study the local deformation fields. The ultrasonic wave velocity variations in flat samples under loading were recorded via the autocirculation method. It is found that the parameters of local deformation distributions and Rayleigh waves depend on the total deformation. The changes in dislocation density during plastic deformation are estimated as well. A linear correlation is established between the applied external stresses and internal stresses calculated according to Taylor’s law for work hardening. The obtained acoustic wave parameters make it possible to estimate the changes in microstructural characteristics of the deformable metal under quasi-static loading. It is shown that the propagation velocities of Rayleigh waves can be used to describe the deformation kinetics in the framework of the autowave plasticity model.