Experimental Investigation on Electrochemical Machining of γ-TiAl Intermetallic

Excellent performance of gamma titanium aluminium (γ-TiAl) intermetallic makes itself to be a feasible alternative for nickel alloys in aero-engine applications. However, γ-TiAl is difficult to cut because of its poor machinability on hardness and low room temperature ductility. Electrochemical machining (ECM) removes electrical conductive material via a controlled electrochemical anodic reaction regardless of its mechanical properties. And inherent characteristics of ECM have advantages over the traditional machining technologies for the machining of γ-TiAl. Orthogonal experiments were conducted to study the effects of process parameters such as applied voltage, electrode feed rate, electrolyte pressure and temperature on material removal rate (MRR), surface roughness (SR) and machining gap (MG) in sodium chloride aqueous solution. The result data of experiments were analyzed by grey relational analysis method. The results indicated that electrode feed rate is the crucial effect on MRR, SR and MG, and the best parameter combination was determined. Finally, a γ-TiAl specimen with the MRR of 273 mm3/min, SR of Ra1.0 μm and MG of 0.31 mm was machined using the optimized parameter combination.