The effect of water quenching on electric resistance and magnetostriction of iron-aluminium alloys has been measured with the forged specimens, and the relations between those changes and the quenching temperature or the alloying concentration have been studied.
For the alloys containing comparatively small amount of aluminium, no peculiar point has been found on the curve of the electric resistance to the quenching temperature. However, in considerably wide range of aluminium content of more than 8 percent, the curve of the resistance to the quenching temperature shows a minimum portion extending over the range of 400° to 750°, which is due to the existence of the new phase Fe13Al3.
For the alloys in the Fe3Al superstructure range, the curve of the resistance to the quenching temperature shows a typical form of the superstructure of A3B type.
The curve of the resistance to the alloying concentration in an annealed state shows a minimum at the composition nearly corresponding to Fe3Al, while when the alloys were quenched from the temperatures above the transformation temperature, the curves show a maximum portion extending over the range of concentration of 11 to 15 percent of aluminium. This may be caused by the fact that the structure of the alloys in the range over the transformation temperature is constructed with two phases, α and α2.
The magnetostriction of the alloys of the new phase and the Fe3Al phase decreases at first slowly and then rapidly with an increase of the quenching temperatures, and becomes very small when the alloys are quenched from the temperatures above 550°. Namely,it has been found that the magnetostriction decreases generally when the permeability increases.
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