Nanostructure formation and steady-state grain size of ball-milled iron powders

Nanocrystalline iron with grain sizes of 13–30 nm has been prepared by mechanical attrition using several different types of mills with different milling intensity. The grain size and the strain of the powders as well as the milling time for achieving the ultimate grain size strongly depend on the milling intensity and the milling temperature. The results obtained under different experimental conditions are discussed in the framework of previously proposed models for the evolution of nanocrystalline grain sizes during mechanical deformation.