Effect of plastic deformation on the acoustoelastic response of some materials

Acoustoelastic birefringence is measured with the acoustic polarimeter by transmitting ultrasonic shear waves at two perpendicular polarizations through the thickness of several uniaxial test specimens. The results are availablefor the following materials: SAE 1010 and SAE 4118 steel, pure titanium, 2024 aluminum and 60\2-40 brass, but are only presented here for SAE 4118 steel and pure titanium. The uniaxial test specimens have been subjected to plastic deformation followed by complete unloading. It is shown that the assumption that the plastic flow leading to the residual-stress state does not change the acoustic response of the material, does not hold for all materials and that further characterization development is required for general quantitative residual-stress determination.