Isochronal annealing behavior of mechanically milled nanocrystalline copper based iron alloys

Abstract Powders of copper, with zero to 50 weight percent iron were mechanically milled for 20 hours in a SPEX 8000 high-energy ball mill. The milled powders were cold pressed into compacts and were isochronally annealed in vacuum to 605 °C. Room temperature thermal diffusivity and x-ray diffracting particle sizes were measured as a function of annealing temperature. The as-pressed specimens had an average diffracting crystallite size of 12 nm and a thermal diffusivity of 0.112 cm 2 /s for copper, which decreased to 0.013 cm 2 /s with the addition of 50% iron. After the five annealing steps, the diffusivity of the copper increased to 0.745 cm 2 /s while in the copper 50% iron increased to 0.146 cm 2 /s.