| Coarse-grained high-purity copper was processed by equal-channel angular pressing (ECAP) through 1-12 passes and then tested under creep conditions at temperature ranging from 423 to 523K. It was found that the creep resistance of the ECAP processed material was markedly improved with respect to unpressed material. The results revealed that the creep behaviour of pressed material strongly depends on the number of ECAP passes. The ECAP material exhibits the highest creep resistance after the first ECAP pass. However, successive ECAP passes lead to a noticeable decrease in the creep properties of the pressed copper. The results indicate conventional power-law creep with a stress exponent of ~5 - 6 which is consistent with an intragranular dislocation process involving the glide and climb of dislocations. |
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