Study of surfactant effects on intermolecular forces (IMF) in powder-mixed electrical discharge machining (EDM) of Ti-6Al-4V

Abstract

Adding Al and Al2O3 powder creates electrical discharge machining (EDM) in a significant machining gap with stable condition. Practically, it is almost impossible to distribute powder particles evenly into the plasma channel. This study investigates the intermolecular process while the plasma channel’s pressure and temperature are changed. In our research, surfactant Tween 80® and its effects on intermolecular forces (IMF) through the plasma channel were investigated to evaluate surface quality. In the first phase of our research, output parameters ran at three experimental blocks (without surfactant, with 21.81 g/l of surfactant, and 43.3512 g/l of surfactant) in 17 runs while adding Al and Al2O3 powders with the design of experience (DOE) method by Design Expert software. Decomposition phenomena (DP), adhesion phenomena (AP), and nonuniform distribution (NUD) of Al and Al2O3 powders demonstrated how new molecules (aluminum trihydride, aluminic acid, methyl(methylene)aluminum, hydroxy(methyl)aluminum hydride, hydroxy(methylene)aluminum, and methyl(oxo)aluminum) were created on the surface element composition. In our experiment, powders’ even distribution when we decomposed Al and Al2O3 created a more stable plasma channel. Consequently, it led to a more balanced heat transfer on the electrodes’ surface. We used scanning of surface quality by field emission-scanning electron microscopy (FE-SEM), electron dispersive spectrum (EDS), and mapping and have shown how to improve the surface defects (hole, crack, and globule). In the second phase of our research, we investigated the intermolecular forces (IMF) on Al–O bond and Al–Al bond. The percentage of elements obtained by mapping analysis of cross-section illustrated that oxygen and aluminum had increased notably when we used Al powder. Considering physical, chemical, metallurgical, and machining time management (MTM) of PM-EDM, we demonstrated that the fine finishing surface improved by 217.7% at Ip = 15 A and Ton = 50 μs and Cp = 5 g/l when the surfactant was added. We compared the best-optimized points in the final phase of our work and measured the recast layer thickness (RLT) after adding Al and Al2O3. As a result, the RTL was removed entirely when Al was added to the dielectric. We have shown that MRR (g/h) and TWR (g/h) were decreased by 5.23 and 113.36%, and SR (Ra) and machining time were increased by 21.75 and 50.84%, respectively. We note that high strength-to-weight ratio and corrosion resistance are essential for many industries, particularly aerospace and biomedical industries. We believe that these industries can potentially benefit from our study.