Effects of Cu on the Microstructure and Properties of Zn-Al Alloy

Cu is the main strengthening element of Zn-Al alloy with a certain degree of solid solution,a white strip e-phase will precipitate when Cu content exceeds the solid solution degree. The effect of Cu content on the microstructure and properties of Zn-Al alloy was studied in this paper. The result shows that: the critical point of e-phase precipitation is between 1.0% and 2.0% of Cu content; In the case of low Cu content,e-phase precipitates little and in small size,the extension rate of alloy increases slowly,the hardness remained unchanged; Increase the copper content suitably will refinement the alloy matrix,improve density and reduce the tendency of shrinkage. Considering various factors,to the ZA27,ZA30 and other high aluminum zinc based alloy,the copper content should be controlled in the best range of 2.5% to 3.5%.