Interface-driven alloying and metallic glass formation in nano-multilayers in an immiscible Y-Nb system

Journal Article · Wed Mar 10 04:00:00 EST 1999 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(98)00430-3· OSTI ID:338438

Chen, Y G; Liu, B X ^[1]

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1. Tsinghua Univ., Beijing (China). Dept. of Materials Science and Engineering

Several new amorphous alloys were obtained in an immiscible Y-Nb system by room temperature 190 keV xenon ion mixing of Y-Nb multilayered films, which were designed to include a sufficient fraction of interfacial atoms and thus possessed a high free energy comparable to that of the amorphous state. In addition, two metastable f.c.c. phases were formed in Y-rich and Nb-rich multilayered films, respectively. The growth kinetics of the f.c.c. phases and their effect on the composition range of amorphization are also discussed. To understand the observed unusual alloying behaviors, a Gibbs free-energy diagram was constructed based on Miedema`s model. The diagram included the free-energy curves of all the involved phases as well as that of the Y-Nb multilayered films including the extra interfacial free energy and thus gave a qualitative and reasonable interpretation to the formation of metastable alloys upon ion mixing. Furthermore, some multilayered films with a sufficient fraction of interfacial atoms were subjected to steady-state thermal annealing, which also resulted in the formation of the Y-Nb amorphous phases, suggesting that alloying in this immiscible system was actually driven by the interfacial free energy.

• OSTI ID: 338438
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 47; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
COMPOSITE MATERIALS
INTERFACES
KINETICS
LAYERS
METALLIC GLASSES
NIOBIUM
PHASE STUDIES
THERMODYNAMICS
YTTRIUM