Observations of an ordered $ Pd_{7} $Eu phase in Pd-Eu alloys

Abstract The Pd-Eu alloys containing 6.1 to 14.3 at% Eu have been studied by metallographic examinations, X-ray diffraction, electron microscopic observations and electrical resistance measurements. The results for the annealed alloys indicate the presence of an ordered phase in the form of a $ Pd_{...
Ausführliche Beschreibung

Abstract The Pd-Eu alloys containing 6.1 to 14.3 at% Eu have been studied by metallographic examinations, X-ray diffraction, electron microscopic observations and electrical resistance measurements. The results for the annealed alloys indicate the presence of an ordered phase in the form of a $ Pd_{7} $Eu superlattice, which is similar to the order found in $ Pd_{7} $R (R=cerium, gadolinium, dysprosium, yttrium or samarium) previously. The order-disorder transition of the ordered $ Pd_{7} $Eu phase in the alloys between Pd-10 and 16.6 ($ Pd_{5} $Eu) at% europium alloys is accompanied with a peritectoid reaction:α-Pd + $ Pd_{5} $Eu ⇄ $ Pd_{7} $Eu at 850 ± 10K. The ordering temperatures for Pd-6.1 and 7.5at % Eu alloys are lower than the peritectoid reaction temperature, and they correspond to the solid solubility limit of europium in theα-Pd phase. Ausführliche Beschreibung