Surface integrity of wire EDMed aluminum alloy: A comprehensive experimental investigation

A comprehensive experimental investigation in surface integrity is characterized by measurement of residual stresses, altered composition of the surface, surface roughness, white layer thickness, heat affected zone, surface morphology, hardness and corrosion resistance tests. The available literature on surface integrity studies was confined to a few of the above aspects and these studies were mostly concentrated on machining of variety of steels, titanium, inconel and nickel based alloys. In this paper aluminum 2014 T6 alloy has been selected for comprehensive study on surface integrity. The parameter settings influenced the residual stresses and a wide range of values were obtained varying from 8.2 to 405.6 MPa. The effect of parameter settings was also evident on the thickness of white layer and surface morphology. No surface cracks were observed at all machining conditions. The diffusion of elements from wire to surface resulted in the formation of various intermetallic compounds like AlCu and AlCu3 which in turn affected the mechanical and chemical properties of the surface. The elastic properties of intermetallics and galvanic coupling created between the aluminum matrix and intermetallics greatly affected the hardness and corrosion resistance respectively.