The paper presents the results of an experimental investigation on the machinability of A390
hypereutectic Al-Si alloy using wire electrical discharge machining (WEDM). The effect of the modification and grain refinement treatments on the microstructure and also on the machining conditions has been evaluated. The process parameters taken into consideration are the average gap voltage (Aj), surface finish type (SF), pulse frequency (F), cutting speed (CS), material removal rate (MRR) and finally the kerf size (KS). The results show that the modification process of A390 alloy has a significant effect on the electrical discharge wire cutting (EDWC) parameters. It has a great influence on the improvement of MRR, CS, and KS. The modified alloy exhibits better machinability conditions when compared with both the as-cast and the grain refined A390 alloys. The grain refined A390 alloy shows lower machinability conditions when compared with the as-cast A390 alloy.