Glass Forming Ability in Pr-(Cu, Ni)-Al Alloys

Abstract

Glass forming ability (GFA) in the Pr-rich Pr-(Cu, Ni)-Al alloys at or near the eutectic points was systematically studied. It was found that the GFA in the pseudo-ternary alloys of Pr-(Cu, Ni)-Al is higher than that of the ternary alloys of Pr-Cu-Al. Two eutectic compositions in Pr-(Cu, Ni)-Al alloys were found by DSC, namely, Pr₆₈(Cu₀.₅Ni₀.₅)₂₅Al₇ and Pr₅₂(Cu₀.₅Ni₀.₅)₂₅Al₂₃ (at %). The later one shows better GFA than the first one. However, the best GFA was obtained at an off-eutectic composition of Pr₅₄(Cu₀.₅Ni₀.₅)₃₀Al₁₆, which can be formed in fully amorphous rod with diameter of 1.5 mm by copper mould casting. The deviation of the best GFA composition from the eutectic point [Pr₆₈(Cu₀.₅Ni₀.₅)₂₅Al₇] was explained in terms of the asymmetric coupled eutectic zone and the higher glass transition temperature Tg on the hypereutectic side.