Reversion Phenomena of Cu-2.46%Fe Alloy and the Effect of Cold Working

The isothermal reversion process of Cu-2.46%Fe alloy, the effect of cold working on the process and the anomalous increase in electrical resistivity introduced by cold working in as-quenched and aged alloys were investigated.The main results obtained were as follows:(1) The amount of reversion increased with increasing difference between aging and reversion temperatures and also, with increasing aging time. (2) The critical pre-aging temperature above which reversion phenomena were not observed did not exist. (3) The reversion process was well expressed by the 1st order rate equation and the estimated value of activation energy for reversion (136 kJ/mol) was considerably smaller than that for impurity diffusion in copper. (4) By cold working before aging, the amount of reversion was greatly reduced in the case of reversion at lower temperatures, but increased more than that in an undeformed specimen at higher reversion temperatures. On the contrary, in the case of cold working after aging, the reversion phenomena were not observed. (5) Astonishingly large increase in resistivity was observed, which could not be explained only by the introduction of dislocations or other lattice defects by cold working. The results seemed to be explained by the redissolution of refined precipitates rather than the refinement of precipitates by cross-cutting action of dislocations.