Separation in ε-Phase of BiPb Alloy under Mega-Gravity

Abstract:

Homogeneous Bi-Pb alloy samples in the ε-phase are treated under mega-gravity centrifugal acceleration field. Atomic sedimentation in solid and associated partial crystallization occurs during the treatment. Small differences of densities in the ε-phase are enhanced under the mega-gravity, and they cause the separation of the ε-phase between fully packed hcp structure of the Bi₃Pb₇ and partially defected hcp structure of the Bi₃Pb_7-δ. The compositional graded superconducting alloy is obtained in the latter. Partially melt-growth occurs in the latter and microstructure of Pb is formed along the gravity field associating with the formation of highly oriented the (211) phase of Bi₃Pb_7-δ. The superconductivity parallel to gravity is Pb, and perpendicular to gravity is Bi₃Pb_7-δ as the result. Superconducting properties differs between the separated two phases.

• Periodical: Defect and Diffusion Forum (Volumes 323-325)
• Pages: 545-548
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.323-325.545
• Online since: April 2012
• Authors: Satoru Okayasu, Masao Ono, Taichiro Nishio, Yusuke Iguchi, Tsutomu Mashimo
• Keywords: BiPb Alloy, Mega-Gravity, ε-Phase

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