*3.1. Electrical Conductivity*

As shown in Table 3, the alloys' electrical conductivity decreased with an increase in the natural aging time. It was because the clustering of solute atoms led to a lattice distortion of the α matrix [23]. The longer the natural aging time was, the worse the lattice distortion became. As a result, the electrical conductivity of the alloys became lower. The changes in conductivity [(CAN−C0)/C0 × 100%] of the NA1d and NA4d alloys of 5.5% and 6.2%, indicated the flattening of clustering with an extension of the aging time from 24 h to 96 h.


**Table 3.** Electrical conductivity of alloys under different heat treatment conditions.

\* Standard deviations are listed in parentheses.

NA4d 30.54 (0.12) 28.65 (0.09) 32.45 (0.09) −6.2 13.4
