Effect of Quenching Condition on Aging of Dilute Al-Ag Alloy

GP zones in Al-Ag alloys have been studied extensively by many workers, but little attention have been paid to the condition of quenching by which super-saturated solid solution would be obtained. In this paper, aging of dilute Al-Ag alloy at 273K after quenching under various conditions was studied by measurement of electrical resistivity. Scattering of the quasi-equilibrium value of resistivity (ρ_E) was not random but closely related to the as-quenched value (ρ₀); ρ_E increased with increasing ρ₀. When the quenching temperature (T_Q) was lower than or equal to 773K, the state at ρ_E was controlled substantially by the concentration of quenched vacancy. On the other hand, when Tq > 823K, GP zones formed during quenching played an important role, instead of quenched vacancies, in determining the state.