MODELING OF MECHANICAL ALLOYING .1. DEFORMATION, COALESCENCE, AND FRAGMENTATION MECHANISMS

A model of the mechanical alloying process, applicable to a single col lision event involving ductile species, is developed. Simple physical models are constructed that allow development of analytical expression s for particle shape and hardness changes during a collision and stipu lation of criteria for particle fracture and cold welding. These provi de a ''snapshot'' of that which transpires during a single collision e vent. The model also accounts for the heterogeneity of deformation wit hin the powder trapped between colliding media. This heterogeneity, to gether with the model criteria, can then be incorporated within a comp utational scheme capable of predictive description of the evolution of powder morphology and properties during mechanical alloying, as will be described in a subsequent article.