Effect of Si and Al on the Microstructure, Mechanical Properties and Machinability of 65Cu-35Zn Brass

Relations between the microstructure, mechanical properties and machinability of as-cast 65Cu-35Zn brass with various amounts of Al (1.89, 3.65 and 4.72 wt%) and Si (0, 0.83, 1.87, 2.28 and 3.62 wt%) were investigated. Both Si and Al initially enhanced the ultimate tensile strength (UTS) and toughness of the brass samples, which led to an improvement in machinability due to a reduction in the main cutting force. A duplex brass with randomly oriented 􀀳 plates in 􀀴’ matrix was found to have the best machinability among the other microstructures. It was found that besides the presence of brittle phases, such as 􀀴’ phase in the microstructure, the morphology and hardness of the phases involved had a signi􀀷cant in􀀸uence on machinability.