Void Growth and Local Temperature Rise in Necking Region of OFHC Ring

The fragmentation tests of high-conductivity oxygen-free copper (M-state TU1) rings have been carried out by the electromagnetically driven expanding ring technique. Using a metallographic microscope, the void growth and coalescence were observed in the necking region of recovery fragment. The void growth conditions in the thin ring were analyzed with a spherical void model. The results showed that the circumferential deviatoric stress is more suitable for describing the void growth in necking zone of the expanding ring. Moreover, the local temperature rise effect of necking region was also discussed. This work may be helpful for the further meso-mechanics studies on necking instability of expanding metal ring.