日本金属学会誌

J. Japan Inst. Metals, Vol. 16, No. 9 (1952),
pp. 503-508

On the Tempering Mechanism of the Quenched β Tin Bronze

Yoshikazu Hosoi


Abstract:

In the previous works, we reported in detail the various characters of β ' and β '' which were determined by H. Imai and M. Hagiya. As the microstructures of the quenched specimens are varied owing to the quenching temperatures and concentration of Sn, many other tempering phenomena do not coincide with each other. We reexamined the tempering mechanism of β tin bronze by means of the dilatometrid and specific heat measurements.
As the microstructures of the quenched specimens are classified into the following three kinds, the results obtained are summarized as follows:
(a) In the case of β Q' only β Q'    (b) In the case of the mixed state,    (c) In the case of β only    (1) Hypo-eutectoid alloys β    (2) Eutectoid alloys β - → β ' - → β '' - → (α + δ)    (3) Hypo-, Hyper-eutectoid alloys β
That is, β : residual β , β Q': quenched aciqular structure, β A': tempered state at about 250° of β Q' or β , is aciqular, β ': tempered state at about 250° of β , is not aciqular, β '': re-arranged state of β A' or β '.
Although the first gradation of β A' or β ' is the tempered state at about 250°, the change to next one is continuously occurring except in the case of (c). The second gradation of β '' which is the lowest electric resistance and max. hardness is the tempered state at about 300°. At the third process of β '' → (α +δ ), it was thought that β '' was thrown into confusion in atomic arrangement at about 300∼330° before the decomposition to (α +δ ) which was accomplished at about 420°.


(Received 1952/1/5)

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