Magnetization measurements and Mossbauer spectrometry have been used among other techniques to characterize the steady-state structure of Fe0.30Cr0.70 powders ground in a high-energy planetary mill and their evolution by subsequent annealing. The as-milled state is a b.c.c heterogeneous alloy with intragranular composition fluctuations of similar to 0.1 in amplitude on a scale of a few nanometres. Isothermal annealing at 623 K results in a coarsening of Fe-rich clusters.