Annealing characteristics of nano-grained oxygen free copper processed by accumulative roll-bonding process.

Annealing characteristics of nano-grained oxygen free copper processed by accumulative roll-bonding (ARB) were studied. A nano-grained oxygen free copper fabricated by 8 cycles of the ARB was annealed at various temperatures ranging from 100 to 300 degrees C for 0.6 ks. TEM observation revealed that the ultrafine grains still sustained up to 150 degrees C, however above 200 degrees C they were replaced by equiaxed and coarse grains due to an occurrence of the static recrystallization. The tensile strength of the copper decreased largely above 200 degrees C. These annealing characteristics of the copper were compared with those of a commercially pure aluminum.