In this study, the evaluation of mechanical properties and microstructures has been carried out on powder metallurgy 60Cu-40Zn alloys with a small amount of transition metals such as chromium and manganese. Raw alloy powder was made by water-atomization process, and consolidated by hot extrusion. When employing chromium as an additive, the tensile strength of wrought alloys drastically increases due to fine grains less than 500nm. In particular 20% increase of TS was recognized compared to the conventional 60Cu-40Zn brass P/M alloy with no additive. There is no morphology change and coarsening of chromium particles, which are dispersed at the grain boundaries of the matrix, during hot extrusion. It suggests fine chromium dispersoids are effective to increase the mechanical properties because of their pinning effect.
