Precipitation reaction in alpha-Cu-Al-Ag alloys

the ag-rich precipitates formation reaction in the cu-9.22%at. al-4.66%at. ag, cu-9.31%at. al-5.83%at. ag and cu-9.37%at. al-7.08%at. ag alloys was studied using microhardness change measurements with temperature and time, differential scanning calorimetry (dsc), scanning electron microscopy (sem) and x-ray diffractometry (xrd). the results indicated that the ag-rich phase formation is an interface controlled process with a zero-order mechanism, due to the amount of unsolved ag that makes the precipitation reaction rate independent of ag concentration.