Fracture of metallic rings during magnetic-pulse shock loading

Metallic rings made of aluminum and copper foils are studied after the action of a distributed radial magnetic-pulse load. Two loading approach modifications allowed us to substantially decrease the period of an applied sinusoidal load and to determine the time from load application to sample failure. A method is proposed to estimate the radial force on a metallic ring from coil turns. The profiles of radial pressure on the inner ring surface are measured, and the circumferential tensile stresses in ring fracture are determined. Microstructural studies of failed ring samples show that they underwent dynamic recrystallization. It is found that, as the operating load period shortens, the fraction of the ductile component in a fracture surface decreases and the samples undergo more brittle fracture.