THE MODELING OF THE MECHANICAL ALLOYING PROCESS IN A PLANETARY BALL MILL - COMPARISON BETWEEN THEORY AND INSITU OBSERVATIONS

In order to understand the mechanical alloying (MA) process in a planetary ball mill (PBM), the kinetics of a ball during milling have been analysed and the calculated ball trajectory is compared with in-situ observations of ball movement. Three different milling modes are deduced from the modelling. Although an experimentally efficient milling mode can be explained from the modelling, there is no good agreement between theory and in-situ observations in the mode of operation of most commercially available PBMs. The present study shows that, in these mills, the MA process should be described in terms of attrition and wear and not in terms of impact as is usually done.