The evolution of the microstructure in amorphous Al85Ce8Ni5Co2 alloy during heat treatment and severe plastic deformation: A comparative study

The effect of three different devitrification routes, i.e. isothermal heat treatment, high pressure torsion and ball milling of amorphous Al85Ce8Ni5Co2 alloy have been studied systematically. The phase selection during the different crystallization sequences is explained by different thermodynamic barriers and growth rates. Low temperature heat treatment results in the formation of alpha-Al and a metastable phase (phi). Although, the nucleation of Al11Ce3 phase is also likely in this temperature range, the lack of its growth is explained by kinetic considerations. Ball milling results in the formation of the stable phase mixture (alpha-Al and Al11Ce3). This process can be considered as a high temperature heat treatment at intermediate pressures (<2 GPa). High pressure torsion at the applied pressure of 6 GPa results in the primary formation of alpha-Al nanocrystals. (C) 2010 Elsevier Ltd. All rights reserved.