A parametric study of electrical discharge machining process parameters on machining of cast Al/B4C metal matrix nanocomposites

Abstract

Aluminium metal matrix nanocomposite reinforced with 0.5 wt% B4C nanoparticles was prepared by a novel ultrasonic cavitation method. The metal matrix nanocomposite was studied microscopically to ascertain the uniform distribution and the degree of dispersion of the B4C nanoparticles within the aluminium metal matrix. Electrical discharge machining was employed to machine the metal matrix nanocomposite with copper electrode by adopting response surface methodology using face-centred central composite design technique. This method has been applied to investigate the influence of process parameters and their interactions. Furthermore, a mathematical model has been formulated in order to study the machining characteristics. It has been observed that pulse current was found to be the most important factor that affects the characteristics of all the three output parameters such as material removal rate, electrode wear rate and surface roughness. The pulse current and pulse on time have statistical significance on both electrode wear rate and surface roughness. Higher pulse off time lowers the electrode wear rate value, whereas both pulse current and pulse on time increase the electrode wear rate. Similarly, surface roughness also increases with increase in pulse current and pulse on time. From the analyses, the optimum combination of the parameters has been identified for the metal matrix nanocomposite. The results obtained from the confirmation experiments were compared with the experimental results and found that errors are in the acceptable range.