Machinability characteristics in Zn-40Al alloy: The effect of addition of copper and silicon and optimization of cutting parameters using response surface methodology

Abstract

In this study, the impacts of Cu and Si additions to Zn-40Al alloy on its microstructural, mechanical and machinability properties were investigated in the turning process. Zn-40Al and alloys containing 2 % Cu and 2 % Si were obtained by PMC. OM and SEM examinations and standard mechanical tests qualified the samples obtained from the mould. Produced alloys were subjected to machinability tests at different V, f and constant DoC parameters using a PVD-ZrN+TiAlN coated insert. CNC lathe was used to determine F, Ra and tool wear in machinability tests. While the microstructure of Zn-40Al comprised of α-Al and Zn-rich η phases, with the addition of 2 % Cu to this alloy, α+ η and Cu-rich ε (CuZn4) were formed in addition to the existing phases. Si particles were found in the microstructure by adding 2 % Si to the Zn-40Al-2Cu. Additions of Cu and Si to the Zn-40Al alloy increased the BH and TS of the material while decreasing the EF. While F, Ra, and BUE decreased with increasing V in the machining of all materials, they increased with the increase in f. The addition of Cu to Zn-40Al decreased F, Ra and BUE. However, the addition of Si to Zn-40Al-2Cu increased it. While a continuous chip was formed in the machining of Zn-40Al, discontinuous chip formation was observed with Cu and Si additions. In Zn-40Al alloy, f and V were found to have the highest statistical significance on F, respectively, while V×Vand f×f were found to have no statistical significance using (Analysis of variance) ANOVA. On Ra, f, f×f and V were found to have the highest statistical significance, respectively, while V×V was found to have no statistical significance. In Zn-40Al-2Cu alloy, f, f×f and V were found to have equal statistical significance on F, while V×V was found to have no statistical significance. On Ra, f and f×f were found to have equal statistical significance, while V and V×V were found to have no statistical significance. In Zn-40Al-2Cu-2Si alloy, f and V were found to have equal statistical significance on F, while V×V and f×f were found to be insignificant. On Ra, f, f×f, V×V and V were found to have statistical significance, respectively. The optimum parameters for minimum F and Ra were calculated as V of 250 m/min and an f of 0.04 mm/rev. It was found that the optimum and experimental results were in good agreement with each other.