Enhanced tungsten wire energy deposition during copper–tungsten intertwined electrical explosion in atmospheric air

Intertwined electrical wire explosion (EWE) is considered as a potential method for large-scale synthesis of high-entropy alloy nanoparticles, while the helical structure, close contact, and different electrothermal properties of wires add to the difficulties of controlling the Joule energy distribution among the wires. In this paper, two very dissimilar materials, copper and tungsten, are chosen as representatives of nonrefractory and refractory metals, and the Cu–W intertwined EWE is compared to parallel EWE of spaced straight Cu and W wires. It is found that for the intertwined load, the majority of the tungsten wire is located in the center and encapsulated by copper vapor, with a low-density spiral plasma belt surrounding the exploding product, and the tungsten wire is transformed into a highly vaporized state instead of a typical core–corona structure, with expansion velocity ∼1.8 times and average energy deposition more than three times that of the parallel load. This dramatic difference is attributed to the high-density and high-pressure vapor medium created by early explosion of the copper wire, which surrounds the tungsten wire and suppresses the formation and expansion of conductive surface plasma channel. These findings can serve to improve the load design for achieving simultaneous dispersion and uniform mixing of dissimilar materials via intertwined EWE.