Effects of Si on the microstructure, ordering transformation and properties of the Cu60Zn40 alloy

• A duplex brass (Cu60Zn40) was developed by additions of Si.
• Phase fractions in the microstructure were changed and β phase was increased.
• Microstructural changes were discussed by electron to atom ratio.
• Dilatometric showed that Si increased the ordering temperature of β to β′.
• The developed lead-free brass alloy can find application in machining.

Effects of small additions of Si to Cu60Zn40 on the properties, microstructure and phase transformation were investigated. It was found that Si promotes the formation of β′ phase and the microstructure of the alloys was changed from duplex α + β′ to single phase β′ brass. Electron to atom ratio was calculated and it was concluded that increment in this ratio led to a decrease in stacking fault energy which had an important role in reduction of the grain size as well microstructural variations in this study. The dilatomeric analysis showed that Si increased the ordering temperature of Cu60Zn40 alloy. Finally, based on the properties, the Cu–Zn40–Si alloys are predicted to have the potential of being an alternative for free cutting leaded brass.