Influence of powder consolidation methods on the structural and thermal properties of a nanophase Cu-50wt%Ag alloy

Nanocrystalline Ag-Cu powder compacts of identical composition have been prepared by 3 different methods: a) compaction of AgCu alloy nanopowder prepared by inert gas condensation of a prealloy (IGC), b) mechanical alloying (MA) of elemental Ag+Cu powder, c) severe plastic deformation (SPD) of a course grained ingot material as well as of a compact of IGC and MA powder. The resulting microstructures have been studied as a function of annealing temperature by means of XRD and TEM in-situ. It is shown that IGC of the prealloy results in a duplex nanostructure, whereas MA and SPD lend to a metastable solid solution phase that decomposes to fine Ag and Cu on heating.