Transient and Steady State Creep of Al-10 wt% Ag and Al-22 wt% Ag Alloys Containing γ\ and γ- Precipitates

Abstract

Al–10 wt% Ag and Al–22 wt% Ag alloys were used to trace the effect of Ag content on the beha vior of both transient and steady state creep. After solid solution treatment, specimens of both alloys were aged at 563, 613 and 683 K for different periods of time (5–120 min) and creep tests were performed at different testing temperatures (353–413 K) by applying a stress of 115 MPa. A higher Ag content in the Al–Ag system is assumed to accelerate the rate of dissolution of GP zones and the rate of formation and growth of g0- and g-precipitates which generally reduced the creep rate, a matter that is confirmed by TEM investigations. Values of the activation energy of the mechanisms operating in both transient and steady state stages were found in the range of 10–23 kJ/mol and 40–55 kJ/mol, respectively.