Surface Integrity Characteristics in Wire Electrical Discharge Machining of Titanium Alloy during Main cut and Trim cuts

Ti-6Al-4V grade titanium alloy is the most popular alloy and is used for a wide range of applications in aerospace, marine, power generation and offshore industries etc., because of its very good mechanical properties such as high tensile strength, fatigue resistance, highest strength-to-weight ratio, extraordinary corrosion resistance and toughness even at elevated temperatures. Wire Electrical Discharge Machining (WEDM) is extensively used for machining of complex shapes in the field of die and mould making, medical, aerospace and automobile industries for machining of too hard materials. WEDM is essentially a thermal process with a complex metal removal mechanism, involving the formation of a plasma channel between the wire/tool and workpiece, resulting in the material removal, which also leads to surface roughness, work hardness, over cut, white layer, heat effected zone, surface structural changes, metallurgical transformations and cracking. These properties determine the operational behaviour of the material and can be included in one term called surface integrity. In this Investigation multi cutting pass i.e. rough/main cut and trim/finish cut approach was adopted to improve the quality of surface characteristics of WEDM surface of Titanium alloy. The results show that the WEDMed surface topography shows dominant micro voids, thick white layer and heat affected zone and even micro cracks at high pulse on time and pulse current and these are low at low pulse on time and pulse current during trim cuts. Further surface topography and micro structural changes were observed through scanning electron microscopy (SEM) micrographs. (C) 2017 Elsevier Ltd. All rights reserved.