The aim of this work was to establish an empirical correlation between strength, hardness and electrical conductivity, i.e. mechanical and physical properties of the EN AW-7075 alloy during the natural ageing.

The results indicate a good correlation between hardness/strength and electrical conductivity. It was found that the correlation between 0.2% proof strength (R_p0.2) and tensile strength (R_m) with hardness (HB) and electrical conductivity, as well as hardness with electrical conductivity, exhibit a nonlinear dependence, with the coefficient of determination, R², between 0.9618 and 1. These relationships can be used for monitoring the ageing and predict the strength by nondestructive testing.