Mechanical alloying in a planetary ball mill : kinematic description

Based on a kinematic modeling of the planetary ball mill, the kinematic equations giving the velocity and the acceleration of a ball in a planetary ball mill apparatus are given. The kinetic energy transferred at the collision event and the shock frequency are also calculated. The confrontation of the calculation results to some experimental results documented in the material literature, shows that the end product depends on the shock power and not only on the kinetic energy. The calculated shock powers correspond to three power levels : - A low shock power level for which crystalline to amorphous phase transitions occur even at extended milling time. - A medium shock power level for which a pure amorphous powder is formed. - A high shock power for which a mixture of crystalline phase and an amorphous one will exist