Effect of Discharge Energy of Magnetic Pulse Compaction on the Powder Compaction Characteristics and Spring Back Behavior of Copper Compacts

Magnetic pulse compaction (MPC) technology had unique compaction advantages compared to traditional powder compaction methods. In this study, the pure copper compacts have been consolidated by MPC technique. The effect of discharge energy on the microstructures, relative density, micro hardness, strain and stress of copper compacts were analyzed via optical microscopy, scanning electron microscopy, hardness tester and FEM simulation. The relationship between discharge energy and spring back was analyzed by numerical calculation. Results showed that the MPC method had the advantages to refine powder particles. The relative density of copper compacts reached 96% when the discharge energy was 9 kJ. Stress concentration was occurred at the upper edge of the powder body, and propagated to the upper center, lower edge and middle position of the powder body. The powder body could have a uniform strain distribution in a short period of time when the discharge energy was greater than 7 kJ. There was a linear relationship between the relative density and the logarithm of Vickers hardness. The axial and radial spring back both increased with the increase of discharge energy. When the discharge energy was 9 kJ, the axial and radial spring back was 2.36% and 0.42%.