Electromagnetically-induced fracture: microstructural evidence of pulse-synchronized crack growth in thin metallic conductors

Application of high-density electric current pulses to pre-cracked metallic conductors can induce rapid crack propagation through electromagnetic body forces generated by current reversal across the crack tip. While this phenomenon has been demonstrated, its associated microstructural characteristics and fracture mechanisms remain insufficiently understood. In this study, we examine the fracture surfaces of thin metallic foils subjected to pulsed electric currents, with and without superimposed mechanical loading. The results reveal pronounced local thinning consistent with plane-stress conditions, the formation of diamond-shaped surface features corresponding to incremental crack advance per pulse, and predominantly transgranular fracture with limited plastic zone development near the crack tip. Notably, these microstructural features remain largely unchanged under combined electromagnetic and mechanical loading. These findings provide direct microstructural evidence of electric current-induced fracture mechanisms and clarify the role of electromagnetic forces in governing incremental crack growth in thin conductors.