Crystallization of Al87Y5Ni8 amorphous alloys doped with Dy and Fe

 

Chem. Met. Alloys 5 (2012) 50-58

 

Taras MIKA, Malgorzata KAROLUS, Lidiya BOICHYSHYN, Grzegorz HANECZOK, Bohdan KOTUR, Viktor NOSENKO

 

Amorphous alloys have been investigated by applying differential scanning calorimetry (DSC), X-ray diffraction (XRD) and high resolution electron microscopy (HREM). Replacement of Y by Dy shifts the primary crystallization to lower temperatures, substitution of Fe for Ni shifts the nanocrystallization to higher temperatures. The RE elements play a dominant role at the first stage of crystallization, the TM elements take part in the crystallization only at the final stage. For alloys with Dy the first two stages of crystallization are attributed to the formation of fcc Al(RE). At the third stage of crystallization, precipitation of the ternary compound RE3Ni5Al19 with an orthorhombic Gd3Ni5Al19-type structure was observed. The interaction between Dy and Fe atoms completely changes the crystallization path of the Al87Dy5Ni4Fe4 alloy, i.e. primary crystallization is attributed to precipitation of unidentified intermetallic compounds and the following stages to the formation of intermetallics isotypic with CeMn4Al8 and YbFe2Al10.

 

 

XRD patterns of amorphous alloys heated up to different temperatures after third stage of crystallization.

 

Keywords

X-ray diffraction / Aluminium alloys / Amorphous alloys / Nanostructured materials / Phase transformation