Machinability Analysis of Ti-5553 Alloy during Electrical Discharge Machining: Evaluation and Optimization of Process Parameters

Ti-5553 alloy is recognized as a next-generation aerospace material; however, it poses challenges in machining due to its unique thermal and mechanical characteristics. Given the scarcity of research available in the literature regarding the machining processes for this alloy, further investigation is essential to establish effective machining strategies. Consequently, this study offers comprehensive experimental analysis to evaluate the machining performance of this advanced aerospace alloy. Ti-5553, is a high-strength near-a beta titanium alloy frequently utilized in specialized aerospace and marine sectors, owing to its remarkable strength and significant hardenability. Designed to provide an excellent blend of mechanical characteristics and improved manufacturability, Ti-5553 consists of roughly 5 wt.% of aluminum, 5 wt.% of molybdenum, 5 wt.% of vanadium, and 3 wt.% of chromium. Given its low thermal conductivity and limited machinability with traditional techniques, electrical discharge machining (EDM) is typically used for its fabrication. This study experimentally investigates the machinability of Ti-5553 using cylindrical copper tool electrodes. Experiments were conducted utilizing an L16 Orthogonal Array (OA) design, where the levels of each process parameter were systematically altered to assess their individual and combined effects. With an emphasis on measures like Material Removal Rate (MRR), Electrode Wear Rate (EWR), and Surface Roughness (Ra) and Surface Crack density (SCD), the machining performance was evaluated utilising a range of input parameters. A multi-criteria decision-making (MCDM) approach, particularly utilizing the Utility Function method, was applied to consolidate various response variables into a unified evaluative framework. Furthermore, analyses of surface morphology and topography were performed on the specimens processed by electrical discharge machining (EDM). The findings indicated a notable decrease in surface crack density (SCD) and white layer thickness (WLT) in samples treated under optimized parameters, in contrast to those machined with random or less effective settings.