Crystallization
of Al87Y5Ni8 amorphous alloys doped with Dy and Fe
Chem.
Met. Alloys 5 (2012) 50-58
https://doi.org/10.30970/cma5.0208
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