Mechanical Alloying Process of Cu-Zn System and Microstructural Change of the Alloy in the Powder Extrusion

Abstract

Mixture of electrolytic copper and atomized zinc powders was mechanically alloyed for various periods of the milling by using an attritor ball mill. Changes of morphology and microstructure of the processed powder with the processing were studied. Content of zinc in the copper particle increases with the increasing of milling time. The zinc(η) phase disappears after the processing for a short period and ε or γ phases are formed at intermadiate stage of the processing. The Cu-30%Zn powder processed for 10hr reaches an equilibrational microstructure, but the alloying process in the Cu-40%Zn powder is late than that in the Cu-30%Zn powder. The mechanically alloyed powders for 5hr were extruded at various temperatures. Microstructure of the extrusions is constituted of an α phase in the Cu-30%Zn and α and 8 phases in the Cu-40%Zn which have fine grain size of about lμm in both extrusions.