부산대학교 도서관

This study investigates the impact of different tool electrode materials on the thickness of the resolidified layer produced by sinking electrical discharge machining (SED-machining) on Inconel 718 alloy. The experiments were conducted with various discharge durations and duty factor levels, using an open voltage of 120 V and a discharge current of 2.4 A. Three grades of tool electrode materials were used: graphite (both polarities), copper, and copper-tungsten. The study found that ED-machining performance improved significantly at a duty factor of 0.33, a discharge duration of 24 μs, and a discharge energy of 6.91 mJ. The material removal rate increased to 1.05 mm3/min with the Graphite (−) tool electrode, while the volumetric relative wear improved to 1.66% with the copper-tungsten tool electrode. X-ray diffraction and scanning electron microscopy analyses revealed phase changes, complex carbide formation, and primary dendritic growth in the recast layer due to abrupt thermal gradient changes and material-electrode interactions. The maximum recast layer thickness was 16.52 μm with the graphite (−) tool electrode, while the copper-tungsten tool electrode produced the smoothest surface with the lowest roughness of 1.3 μm. The copper tool electrode yielded the thinnest recast layer at 9.08 μm. [ABSTRACT FROM AUTHOR]