Driving mechanisms on mechanical alloying: experimental and molecular dynamics discussions

Mössbauer spectroscopy, X-rays diffraction and differential scanning calorimetry are used to study a fcc Fe 45at.% Cu nanocrystalline solid solution obtained by mechanical alloying. These results supported by molecular dynamics simulations are used to discuss some models in mechanical alloying. The kinetic energy ou even a function of it appears to be the parameter driving the reactions inside the mill. Impact frequency and powder mass seem to contribute only on the time scale. A capilarity pressure is shown to exist in order to alloy the nanocrystalline grains. Despite this, an extra energy, provided by the shocks, is shown to be necessary to start up the process. Final product appears to be a function of strains/stress fields and material response.