The persent investigator has measured the temperature change of specific heat of iron-aluminium alloys by the method originated with C.S. Smith with the forged specimens and has proposed a speculation on the transformation of the Fe3Al superstructure and the new phase, based npon his results.
The new phase, found in the previous investigation, has been considered as a short range ordered superstructure of Fe13Al3 and it exists in the range of aluminium content of 5.04 to 13.15 percent ; in the aluminium content of more than 11.6 percent coexisting with the Fe3Al superstructure. The transformation temperature of the new phase is highest at the concentration of about 10 to 11 percent of aluminium, and the transformation heat quantity is maximum at about 11 percent.The transformation of the new phase shows a very conspicuous hysteresis.
For the superstructure alloys containing more than 13.9 percent of aluminium,a short range ordered Fe3Al exists in the wide temperature range higher than the transformation temperature, while for the alloys containing aluminium less than 13.9 percent, the ordering in a short range becomes considerable at the comparative low temperatures near the transformation temperature.
Finally,to summarize the results mentioned above,a new phase diagram of the ferromagnetic range of iron and aluminium alloys has been constructed.
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