Study of Surface Characteristics of Additively Manufactured γ-TiAl Intermetallic Alloy Processed by Wire Electro-Discharge Machining (WEDM) for Aerospace Applications

This research explores the experimental analysis of the post-processing of Electron Beam Powder Bed Fusion (EB-PBF)-manufactured Ti-48Al-2Cr-2Nb alloy by Wire Electric Discharge Machining (WEDM) with a focus on machining ability and analyzing the surface characteristics. In general, [Formula: see text]-TiAl alloys have been considered as one of the most difficult-to-machine materials due to their poor machinability. WEDM is a promising alternative to cut difficult-to-machine materials with complex angular and curved features. In the present study, the Grey-Taguchi approach was employed to systematically identify the experimental parameters through an orthogonal array design. Using the Taguchi framework, regression analysis was performed to construct predictive models for evaluating surface roughness and flatness. This was followed by an Analysis of Variance (ANOVA) to estimate the statistical implications and effectiveness of the selected process parameters. The findings revealed that pulse-on time (T[Formula: see text] had the most significant impact on surface quality, followed by servo voltage (SV), wire feed (WF), and pulse-off time (T[Formula: see text]. Under optimized conditions, that is, 5 [Formula: see text]s of T[Formula: see text], 8 mm/min of WF, 60 V of SV, and 50 [Formula: see text]s of T[Formula: see text], the best surface finish (Ra) of 1.90 [Formula: see text]m and flatness of 0.001 [Formula: see text]m were achieved. The predictive model for surface roughness demonstrated strong agreement with experimental results, showing a prediction error between 0.5% and 10%. Analyses conducted using Scanning Electron Microscopy (SEM) and Energy Dispersive [Formula: see text]-ray Spectroscopy (EDX) verified that discharge energy and pulse-off time (T[Formula: see text] influenced the machined surface characteristics by altering the material’s microhardness, white layers, and microcracks.