THE MICROSTRUCTURE AND PROPERTIES OF WATER ATOMIZED AND EXTRUDED CU-CR ALLOY POWDERS

Cu-Cr alloy powders were produced by water atomization, and were consolidated by warm extrusion, after canning and degassing. The lattice parameter of the copper-rich solid solution in powders was determined by X-ray diffraction. A significant increase in the extension of the solid solubility of chromium in copper was achieved with water atomization. The microstructures of the as-atomized powders and extruded bar were examined by transmission electron microscopy. A fine grain structure is produced by rapid solidification. A banded structure is observed in the extruded material. Coherent precipitation is seen in the heat-treated material. A two-fold increase in the tensile properties, with respect to the conventionally processed Cu-Cr alloys, is obtained. Electrical conductivity is slightly reduced.