Nanostructure evolution and mechanical properties of rapidly solidified Al-Ni-RE (Y, Ce) alloys

The melt spun and subsequently annealed Al-Ni-RE (Y, Ce) alloys with the composition of Al88Ni6Y6, Al86Ni6Y8, Al86Ni5Y6Ce2 and Al84Ni6Y6Ce4 (at%) were investigated through differential scanning calorimetry (DSC), transmission electron microscopy (TEM), X-ray diffraction and nanoindentation. The influence of RE (Y, Ce) elements on the thermal stability and mechanical properties of Al-Ni-RE alloys have been studied. The glass forming ability, thermal stability and hardness value have been increased with substitution of Al atoms by RE atoms. TEM analysis confirm that the structure consists of alpha-Al nanoparticles embedded in an amorphous matrix produced by non-isothermal annealing of initially fully amorphous Al86Ni6Y6Ce2 ribbons. Significant changes in hardness value occur due to changes of both chemical composition and crystalline structure. The maximum hardness of 7.30 +/- 0.58 GPa is obtained in the Al86Ni6Y6Ce2 alloy by annealing at 618 K with a mixed microstructure of fine Al nanoparticles and nano-Al3Ni intermetallic compound in an amorphous matrix. (C) 2013 Elsevier B.V. All rights reserved.