Experimental study and analysis on the electrically-assisted tensile behaviors of Inconel 718 alloy

The effect of pulsed current on tensile deformation of Inconel 718 superalloy with different initial microstructures was studied by experiment, which is of great importance for the subsequent application of electrically-assisted manufacturing (EAM) technology. The results show that the pulsed peak current with a density of 10 A/mm2 has no effect on stress responses, while the yield strength (YS) and ultimate tensile strength (UTS) are reduced when the peak current density is above 25 A/mm2. The higher peak current density and frequency lead to more obvious thermal effect and thus result in the decrease of YS, UTS and elongation. For samples cutting from different directions, i.e. transverse direction (TD) and rolling direction (RD), no difference in YS can be observed with EAM. For samples with different initial microstructures, e.g., the as-received and the heat-treated samples, more significant decrease in flow stress and higher elongation can be observed for the former than for the latter. Notably decreasing YS was achieved without deteriorating the ductility at a peak current density of 25A/mm2 and a frequency of 400Hz. The physical mechanism for the obtained rules was revealed.