| Effects of the cobalt content on the recrystallization temperature were studied in Ni-Co binary alloys. As the cobalt content was decreased from 65wt% Co, the number of dislocation cell in unit area of the Ni-Co alloy cold-rolled 90% at room temperature was increased, and the dislocation cell wall thickness and dislocation density in it became smaller. The specific peak area in the DTA curves of the cold-rolled Ni-Co alloys was almost constant regardless of the cobalt content below about 30wt%, but was increased rapidly with increasing the cobalt content above 30wt%. The recrystallization temperature of the Ni-Co binary alloy was increased with increasing the cobalt content below about 30wt%, but was decreased with increasing the cobalt content above 30wt%. From this result, it was concluded that the recrystallization nucleation occurred by the cell coalescence in the composition range below about 30wt% Co, but in the composition range above the 30wt% Co the nucleation occurred under the stored energy acting as driving force for the nucleation like the classical homogeneous nucleation theory in phase transformation. |
|
