Analysis of residual stresses in particulate reinforced aluminium matrix composite after EDM

Abstract

This paper reports the effect of properties of three types of particulate reinforced metal matrix composite materials (65 vol.-%SiC/A356·2, 10 vol.-%-SiC–5 vol.-% quartz/Al, 30 vol.-%SiC/A359) and machining parameters on residual stresses induced in the machined surface during powder mixed electric discharge machining. Three electrode materials (Cu, Gr and Cu–Gr) and three machining parameters, namely, peak current and pulse (on/off) duration, are varied to determine the magnitude of induced residual stresses. The result shows that the workpiece, electrode material properties, and pulse off time significantly contribute in the formation of residual stresses. Concentration of reinforced particulates and matrix conductivity also play a vital role in the development of residual stresses. The deposition of disintegrated particles of composite electrode (Cu–Gr) results in high magnitude of residual stresses.

Keywords:

• Electric discharge machining
• Metal matrix composites
• X-ray diffraction
• Residual stress