Elastic and plastic strain effects on eddy current response of aluminium alloys

This paper presents the study of correlation between elasto-plastic state of metallic components and their eddy current (EC) response. Aluminium alloy samples are plastically deformed by tensile loading up to 10% of plastic strain with step of 0.5%, and elastic dependencies of EC response are obtained for each plastic state. The method demonstrates capability of separating elastic EC responses according to the amount of plastic strain. The real part of EC response is found to be sensitive mainly to elastic stress. In contrast, the imaginary part of EC response is sensitive mainly to plasticity, with dependence being monotonic in the absence of strain-hardening. Strain-hardenable materials represent some challenge for the method due to non-uniform plastic flow.