ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract The steady-state coupling equations of directional solidification of Al-Al2Cu (ε=0.94), Sn-Pb (ε=0.59)and Al-Si (ε=0.17)eutectics have been solved numerically. The profiles, splitting features and supercooling of the solidifying interface were investigated in detail as functions of the lamellar spacing. It was found that when supercooling, ΔT 0, at the three-phase conjunction point reaches its minimum value, min (ΔT 0), the solidifying interface profile of one lamellar phase was in the critical splitting state (marginally stable state) and that of the other lamella was super-stable. Langer's marginal stability theory of lamellar eutectic solidification with a planar interface was extended to the case with a curved interface, and a geometrical model of the spacing selection has been suggested (critical splitting state of one lamella's solidifying interface). The general scaling law of the spacing, derived according to this theory, was found to be consistent with the similarity law recently derived by Kassner and Misbah; it is also supported by experimental results. Another geometrical model of the spacing selection was found, where the solidifying interface profile of one lamella became split and other lamella's profile was in the critical splitting state. The experimental data for directional solidification of Al-Si eutectic showed that the irregular eutectics have a spacing selected according to this mode.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01117624
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