Experimental investigation on titanium alloys for machining of stepped circular holes using ultrasonic-assisted hybrid ECM

Abstract

In the recent development of high-performance gas turbine engine, there is a tendency to design the cooling holes in order to improve the heat transfer and cooling efficiency. Titanium alloy is the most preferred material for these blades. It is hard material, and hence, the traditional drilling is not appropriate for “Ti” alloy. This research presents the design and optimization required to manufacture contoured holes on a titanium-based superalloy using hybrid electrochemical machining (ECM) under different operating conditions. The circular holes are developed and are analyzed by ANOVA. The experimental results are further optimized using a Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. The voltage (V), feed rate (f1), and feed rate (f2) were identified as the most influencing factors which are further used for stepped circular hole machining. A design of the experiment is also optimized using the TOPSIS method. The obtained experimental results are verified using a SEM analysis to confirm the uniformity of the machined surfaces and the inverse relationship of the overcut with the increasing values of the voltages and feed rates. Optimal machining conditions for the stepped hole machining were determined for voltage 18 V, feed rate “f1” at 0.8 mm/min, and feed rate “f2” at 1.35 mm/min. Graphical Abstract: (Figure presented.).