LAUSR

In the present paper, the aging precipitation and coarsening of disk-like δ-Ni2Si particles in Cu and Cu-10Zn alloys aged at 450 °C have been investigated by hardness, electric resistivity measurement and transmission electron microscopy observation. The coarsening dynamics of the average diameter of the δ-Ni2Si particles coincides with the t1/3 time law for both alloys. The coarsening of the diminution of supersaturation related to aging time t coincides with the t−1/3 time rule. Adding Zn to the Cu-Ni-Si alloy increases the growth and coarsening rate of the particles mainly because of the increased diffusivity D of the δ-Ni2Si particles in the matrix. The value of D of the δ-Ni2Si particles in the Cu-xZn (x = 0, 10 wt.%) matrix and the Cu/δ-Ni2Si interfacial energy γ are independently calculated by using the Lifshitz–Slyozov–Wagner theory which was extended to include disk-like particles by Boyd and Nicholson. The values of D and γ increase from 0.77 × 10−19 to 2.21 × 10−19 m2/s and 0.19 to 0.63 J/m2, respectively, when Zn is added to the Cu-Ni-Si alloy. These calculations and the analysis show that the properties of Cu-Ni-Si-Zn alloy can significantly be enhanced by reducing the aging temperature.