The properties of high-energy milied pre-alloyed copper powders containing 1 wt.% Al

Abstract

The microstructural and morphological changes of inert gas atomized pre-alloyed Cu-1 wt. % A1 powders subjected to hith-energy milling were studied. The microhardness of hot-pressed compacts was measured as a function of milling time. The thermal stability during exposure at 800 degrees C and the electrical conductivity of compacts were also examined. During the high-energy milling, severe deformation led to refinement of the powder particle grain size (from 550 nm to about 55 nm) and a decrease in the lattice parameter (0.10%), indicating precipitation of aluminium from the copper matrix. The microhardness of compacts obtained from 5. h-milled powders was 2160 MPa. After exposure at 800 degrees C for 5 h, these compacts still exhibited a high microhardness value (1325 MPa), indicating good thermal stability. The increase of microhardness and good thermal stability is attributed to the small grain size (270 and 390 nm before and after high temperature exposure; respectively). The room temperature electrical conductivity of compacts processed from 5 h-milled powder was 79 % IACS.