Nonlinear characterization of stress wave factor for plastic damage of A7N01P-T4 aluminum alloys

Abstract

This paper studies the relationship between plastic damage and the ultrasonic nonlinear coefficient by changing the interior plastic strain of A7N01P-T4 aluminum alloys. An effective evaluation of the plastic damage of tensile test specimens was made by comparing with two different nonlinear ultrasonic detection methods, namely, nonlinear longitudinal wave method and surface wave method. The nonlinear coefficient of the stress wave factor was introduced to characterize the plastic damage for metallic materials. The results showed that with the increasing plastic damage degree, the nonlinear coefficient increased slowly at the early stage of yield hardening (3%) and then increased rapidly at the middle stage (3–5%). It is concluded that the nonlinear longitudinal wave is more suitable for point measurement and its sensitivity is lower than that of the longitudinal wave.