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Characterization of Rapidly Solidified Nd–Al and Nd–Ag Eutectic Alloys in Drop Tube
Author(s) -
Büyük Uğur,
Erol Mustafa,
Volkmann Thomas,
Herlach Dieter M.
Publication year - 2015
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201400131
Subject(s) - eutectic system , materials science , nusselt number , drop (telecommunication) , prandtl number , microstructure , metallurgy , thermodynamics , reynolds number , heat transfer , turbulence , telecommunications , physics , computer science
Nd–14.2 at%Al and Nd–20.0 at%Ag eutectic alloys were containerlessly solidified in an 8 m drop tube. The droplets were undercooled during the free fall in about 1 s under reduced gravity condition in He atmosphere. The cooling rates at the solidification temperature were computed as a function of droplet size by making use of heat balance calculations. They were ranging between 40 × 10 3 and 0.8 × 10 3 K s −1 for droplets in size range of 100–900 μm diameters. Nusselt, Reynolds, and Prandtl numbers of the droplets were calculated. Microstructures of the alloys were analyzed and eutectic spacings were determined. Microhardnesses of the droplets with different sizes were measured to reveal a dependence on the cooling rates with which the droplets are solidified.