Production of nanocrystalline powders by high-energy ball milling: model and experiment

A model of high-energy ball milling of powders has been proposed. It is demonstrated that part of the energy is consumed for initiation of microstrains epsilon during milling and, hence, the process of the powder grinding is decelerated. An analytical expression has been deduced describing the size of nanocrystalline powder particles as a function of the milling time. The model and the experiment have been compared, using a powder of tungsten carbide ( WC). The average size of the particles and the value of the microstrains in the ball-milled powder were determined by an x-ray method from broadening of diffraction reflections. The size of the particles was also evaluated using scanning electron microscopy and the sedimentation method.