日本金属学会誌

J. Japan Inst. Metals, Vol. 2, No. 2 (1938),
pp. 77-90

On the Volume Changes of the Pb-Cd and Sn-Bi Systems during Solidification

Takao Takase1

1大阪帝國大學金屬工業研究所

Abstract:

The volume changes during solidification of the Pb-Cd and Sn-Bi systems which have a simple eutectic type and low melting point have been studied by means of a thermo-balance. The main results of the present investigation are as follows :-
(1) The specific volume changes, the percentage of those changes during solidification, the specific volumes (densities) at solidification temperature and the linear expansion coefficients from room temp. up to the melting point of four pure metals, Pb, Sn, Bi and Cd, have been determined. These results concide with the previous investigations.
(2) The interesting relations between the volume changes during solidification and compositions or diagrams of the above two alloys series have been found: the relation between the volume change by eutectic and composition is a straight line, but that between primary change, and compositions is a curve; therefore the relation between the total volume change (the sum of eutectic and primary volume changes) and composition is not a straight lines but curves having one max. point on each side of the eutectic composition. Regarding the cause for this phenomenon, a most probable explanation has been given.
(3) For the solidification mechanism of the eutectic alloy, it is suggested that in molten state, the composition metals of the eutectic alloy are undercooled to the eutectic temp. by own expansion coefficients and then solidify. According to this consideration the writer proposed a theoretical formula and calculated values for above two alloys series which were found to be in good agreement with the experimental results.
(4) The specific volumes at various temp. on the solidification have also been calculated.


(Received 1937/10/19)

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