Effects of diffusion induced recrystallization on volume diffusion in the copper-nickel system

The effects of diffusion induced recrystallization (DIR) on volume diffusion in the Cu(Ni) system was investigated. Cu-Ni diffusion couples annealed at 500, 550, 600, and 650 °C for 120 and 200 h were used to calculate the volume diffusion for the Cu(Ni) binary system. Using characterization techniques such as focused ion beam (FIB) and transmission electron microscopy (TEM), observation of the interdiffusion zone revealed areas containing DIR and nonDIR. The volume diffusion of Ni into Cu across the non-DIR regions were calculated using the Boltzmann-Matano (B/M) method at 1 wt% Ni to be 8.05E-21, 9.88E-20, 4.53E-19, 2.67E-18 m 2 /s for 500, 550, 600, and 650 °C, respectively. Calculations of volume diffusion across the DIR zones were approximately three to four orders of magnitude higher than the volume diffusion based on the non-DIR information. Literature values for volume diffusion in the Cu(Ni) system are also higher than the non-DIR values by approximately one order of magnitude, implying that previous values may contain grain boundary contributions.  2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.