Aging Characteristics and Effects of Plastic Deformation on Precipitation in Al-4% Cu and Al-20% Ag Alloys with or without Trace Elements

Abstract

The experiments have been carried out to examine the effects of plastic deformation and addition of small amounts of third elements on the aging process in Al-4%Cu and Al-20%Ag alloys by the X-ray Laue method, micro-hardness measurements, transmission electron microscopic studies and resistivity measurements. In binary Al-4% Cu alloys, the plastic deformation immediately after quenching retards the growth of G.P. (1) and G.P. (2), and accelerates the nucleation of the θ′ phase. In Al-20% Ag alloys, similar results are obtained. In undeformed ternary Al-Cu alloy, the retarding effects of third elements on aging become stronger in the order Be<Ti<Zr. In Al-Cu-Zr alloys, the plastic deformation much accelerates the growth of G.P. (1). The role of excess vacancies on aging and the interaction between dislocation and precipitates are discussed.