The effects of Ni, Co, Ag, Bi and P upon the recovery of work-hardening were studied in single crystals which contained almost-spherical a-Fe particles. Addition of these elements did not change the softening mechanism. That is, Orowan loops which were located around the particles climbed and disappeared via pipe diffusion through their cores. In samples which contained Ni, Co, Ag or Bi, the loop climb-rate decreased with increasing concentration of the addition, and eventually reached a steady value. At this stage, the activation energies for pipe diffusion were equal to about 70% of that for bulk diffusion of the element in Cu. Addition of the elements also increased the frequency-factor for pipe diffusion. The activation energy and frequency-factor were unchanged by P additions. It was shown that these effects were caused by the presence of significant amounts of the element in the proximity of the dislocation core. Softening after work-hardening, in Ag-added single crystals which contained rod-shaped a-Fe particles, was also examined with regard to 2 types of geometrical relationship between the Orowan loops and the habit-plane of the particles. In one case, the Orowan loops touched the habit plane during climbing. In the second case, they did not. Although Ag additions resulted in an increase in activation energy and frequency-factor in both cases, the former process was associated with smaller values. This was because the amount of Ag segregation on the habit plane was lower than that on the matrix/particle interface.

Influence of Alloying Elements (Ni, Co, Ag, Bi, P) on Annihilation of Orowan Loops around a-Fe Particles in Cu Matrix R.Monzen, J.Asaoka, K.Kita, K.Kitagawa: Journal of the Japan Institute of Metals, 1998, 62[4], 363-8