Structural changes during mechanical alloying and heat treatment of Al_65Cu_20_Fe_15 alloy

摘要

Structural changes during mechanical alloying andpost-heat treatment of Al_(65)Cu_(20)Fe_(15) alloy powder werestudied by using X-ray diffractometry, transmission electronmicroscopy and thermal analysis. Al_(65)Cu_(20)Fe_(15) alloysample processed for 10 hrs showed a layered structure consistedof Al, Cu and Fe containing layers. DSC of the specimens showedtwo broad exothermic peaks: one is weak in the temperature rangeof 300~390 deg C and the other strong 390~480 deg C. The firstexothermic peak seems to correspond to the formation of Al_2Cuand Al_7Cu_2Fe phases and the second peak to the formation ofmixture of quasicrystalline approximant and ordered Al(Fe, Cu)#beta# phases from the previously formed Al_2Cu, Al_7Cu_2Feand unreacted Fe phases. Al_(65)Cu_(20)Fe_(15) alloy sampleprocessed for 120 hrs showed a homogeneous distribution of nanoscaled Al(Fe, Cu) #beta# particle in an amorphous matrix. Duringheat treatment of the sample, the microstructure transformed into amixture of ordered Al(Fe, Cu) #beta# phase and Al13Fe4. Directformation of quasicrystalline phase was not observed in as-mechanically alloyed Al_(65)Cu_(20)Fe_(15) alloy powder.