Investigation on the Wire Electric Discharge Machining Performance of artificially aged Al6061/B₄C composites by Response Surface Method

Present research work is focused on investigation of material removal rate in Wire-ED Machining (EDM) of artificially aged Al-6061/ B₄C reinforced composites with 2-6 wt.% in peak aged condition. Combined effect of B₄C and artificial aging at 100°C improved the hardness by 20 - 170% under as cast and artificially aged condition. Initially the wire EDM experiments are conducted on Al6061 alloy and then the process parameters such as current, pulse-on time (t_on) and pulse-off time (t_off) are optimized to obtain the high material removal rate (MRR). At optimized conditions test samples with various % of B₄C are machined to study their influence on MRR. The study revealed that current and t_off had a significant influence. MRR increased as current is increased and it decreased as t_off is increased. Maximum MRR at optimum settings, current : 5.53 A, T_off: 10 µs and T_on: 36.46 µs is 2.45 mg/min. Considering the limitation of the experimental set up the modified optimum settings (T_off: 10 µs, T_on: 30 µs and current : 5 A) resulted in average MRR of 2.39 mg/min with deviation of 0.20 mg/min. The study showed that there is no significant difference in MRR and the morphology of the machined surface with respect to test samples of different % of B₄C particles as reinforcement in Al6061 composite.

Keywords:
Wire-EDM; Artificial aging; Al6061/B₄C composite; pulse on time; pulse off time