It is a well-known fact that the magnetic properties of a reversible iron-nickel alloy, especially of 78.5% Ni, are largely modified by rapid cooling from 600°, namely, by the so-called permalloy treatment. Two theories have been advocated on the physical meaning of this treatment; one is the super lattice (Ni
3Fe) theory, and the other the plastic flow theory in magnetic domain. We carried out an experiment on the change of Young's modulus by the permalloy treatment and attempted to decide which theory is more reasonable of the two. By the lateral vibration method we measured the modulus of specimens cooled slowly after vacuum annealing at 1000_??_1100° for 20 hours, and then of specimens cooled rapidly from 600° in air after reheating to 1000°. Rapid cooling general, seems to decrease Young's modulus in both ranges reversible and irreversible. The marked decrease of the modulus occurs in the magnetically modifiable range of alloys (50_??_85% Ni). Moreover, the curve of the percentage decrease of the modulus to composition is quite similar to that of magneto-striction in longitudinal magnetic field. Similarity of these two curves suggests that some relation may exist between the change of Young's modulus by rapid cooling and the degree of plastic flow in magnetic domain. The decrease of magneto-striction by cooling in field was related directly to the degree of plastic flow of magnetic domains by Bozorsh and Dillinger, and afterwards was supplemented by Becker and During as a trans formation from cubic atom arrangement to somewhat tetragonal one. The decrease of Young's modulus by rapid cooling may be attributed to the degree of transfor-mation of atom arrangement from cubic to tetragonal.
抄録全体を表示