INFLUENCE OF POWDER CONSOLIDATION METHODS ON THE STRUCTURAL AND THERMAL-PROPERTIES OF A NANOPHASE CU-50WT-PERCENT-AG ALLOY

Nanocrystalline Ag-Cu powder compacts of identical composition have be en prepared by 3 different methods: a) compaction of AgCu alloy nanopo wder prepared by inert gas condensation of a prealloy (IGC), b) mechan ical alloying (MA) of elemental Ag+Cu powder, c) severe plastic deform ation (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-sit u. It is shown that IGC of the prealloy results in a duplex nanostruct ure, whereas MA and SPD lend to a metastable solid solution phase that decomposes to fine Ag and Cu on heating.