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Local Atomic Structures and Plastic Deformation Modes in the Supercooled Liquid State of La55Al25Ni20

Published online by Cambridge University Press:  17 March 2011

Tadakatsu Ohkubo
Affiliation:
Institute of Science and Industrial Research, Osaka University, Osaka, 567-0047, JAPAN
Yoshihiko Hirotsu
Affiliation:
Institute of Science and Industrial Research, Osaka University, Osaka, 567-0047, JAPAN
Akihisa Inoue
Affiliation:
Institute of Materials Research, Tohoku University, Sendai, 980-8577, JAPAN
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Abstract

An in-situ electron diffraction structure analysis of La55Al25Ni20in the supercooled liquid temperature range (ΔTx) revealed a gradual structural change with a local phase separation due to strong atomic correlations especially of La-La and Al-Ni. On the basis of the structural data, structure models corresponding to the structures at temperatures between Tg and Tx were constructed using molecular dynamics (MD) simulation technique. These constructed structure models were then utilized for MD simulations to understand plastic deformation in the supercooled liquid state under a constant strain-rate. A larger elongation was obtained for the structure in the middle of the ΔTx range, but for the structure near Tx the elongation was relatively smaller which was supposed to be due to the local phase separation. These simulation results correspond well to the experimental elongation behaviors in the superplastic deformation that the elongation is enhanced in the middle of ΔTx but suppressed as the temperature is increased towards Tx.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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