Compression creep of copper under electric current studied by a spark plasma sintering (SPS) apparatus

A spark plasma sintering (SPS) apparatus was successfully employed to perform uniaxial compressive creep tests on pure copper under a stress of 30 MPa in the 400-600 °C temperature range. By utilizing two different configurations, the creep experiments were conducted without or with a low-density pulsed direct electric current (~ 6-7 A/mm2) passing through the samples. It was found that under the influence of the applied electric current, the creep rate increased significantly, while the extent of the effect diminished with temperature. The apparent activation energy for creep with applied current decreased from 110 to 66 kJ/mol. This was attributed to the effect of current on the thermally-activated process and dislocations motion. No distinct evidence that the electric current affects the microstructure was observed.