Material Removal Rate Enhancement Induced by Electrochemical Discharge Machining for Refractory High-Entropy Alloys Compared with EDM

Refractory high-entropy alloys (RHEAs) are categorized as difficult-to-machine materials due to their excellent mechanical properties. Electrical discharge machining (EDM) is a special processing method for RHEAs, which faces challenges such as low machining efficiency. In this work, electrochemical discharge machining (ECDM) was proposed for (TiVZrTaW)_99.5N_0.5 and (TiVZrTa)W₅ (at. %, denoted as W20N0.5 and W5, respectively) RHEAs, and their machining performances were investigated and compared with EDM. At a peak current of 25 A, the material removal rate (<i>MRR</i>) using ECDM is more than twice that of EDM for W20N0.5 (reaching to 1.24 mm³/min) and 1.5 times higher than that for W5. Both W20N0.5 and W5 RHEAs exhibited higher <i>MRR</i> in ECDM based on the analyses of the influence of top diameter, bottom diameter, machining depth, and surface roughness (<i>R</i>a). The process and mechanisms of material removal were examined through the microstructural morphology and elemental distribution analyses. This work proposed a more effective route for machining RHEAs by ECDM compared to the conventional EDM.