Mikio Yamamoto : Young's Modulus of Elasticity and Its Variation with Magnetization in Ferromagnetic Nickel-Copper Alloys. Young's modulus of elasticity and its change with magnetization, that is, the de-effect in the annealed state of ferromagnetic nickel-copper alloys, have been measured in detail at ordinary temperatures by the method of magnetostrictive oscillation, which was described in a preceding paper. The measured range of magnetic field for the de-effect is up to about 900 oersteds. The general course of the change of Young's modulus accompanied by an increase of magnetic field or intentisity of magnetization, is similar for alloys of any compositions here investigated. The modulus increases quickly at weak fields, but the rate of increase diminishes gradually with growing field, finally the change of the modulus attaining a saturation. As for the relation between the change of the modulus and the intensity of magnetization, the modulus increases more and more rapidly from the low to the high magnetization range, but once the rate of its increase diminishes slightly, and afterwards- the modulus shows a rapid increase in the magnetization range adjacent to its saturation. The detailed observation of the de-effect reveals, however, the following two particulars. In the first place, Young's modulus in alloys of an intermediate composition range (5-21 weight percent copper) decreases, that is, de/e(the change of the modulus, relative to that in the non-magnetized state) becomes negative, though slightly, at first at very weak fields or in the very low magnetization range, and makes a minimum before it increases rapidly with further increasing field or magnetization. Secondly, in nickel and alloys of high nickel compositions (below 15.5 percent copper), the modulus increases somewhat rapidly again in the field range just preceding the saturation. The saturation value of the relative change of Young's modulus, (de/e). decreases with increasing copper content, but the course of decrease is by no means monotonous, making an inflexion in the composition range of 1015 percent copper. An extrapolation of the (de/e)o, vs. composition curve shows that the de-effect vani shes at the composition of about 34 percent copper, and this composition coincides with that at which the ferro magnetism disapears at ordinary temperatures. The curve calculated on the basis of theories agrees qualitatively well with the measured one. It is also shown that a quantitative difference recognized between (de/e) vs. composition curves of the two sets of alloys of different origins can be explained in terms of the difference in their initial susceptibilities. The rate of a rapid increase of Young's modulus at weak fields, the intensity of magnetic field at which its increase saturates, its temporary decrease in the very weak field or magnetization range, and the intensity of magnetic field at wihch its secondary somewhat rapid increase occures, all decrease with an increase of copper content. The relation between Young's modulus at the non-magnetized state and the composition shows a con siderably complicated aspect. The modulus increase at first with an addition of copper to nickel, makes a maximum at about 10, a minimum at about 15, and again a maximum at about 20 percent copper, and then it decreases with further increasing copper. The existence of the minimum at about 10 percent copper has never been found. (Received February 10, 1942)
Table 1 Compositions and "dimensions of specimens used.
Fig. 1 Magnetization curves of ferromagnetic nickel-copper alloys (A-alloys). Table 2 Experimental data of the change of Young's modulus of elasticity with magnetization (relative to that in the non-magnetized state) in ferromagnetic nickel-copper alloys (A-alloys). H denotes the external magnetic field, de/e the relative change of Young's modulus with magnetization, and I the intensity of magnetization.
Fig. 2 Relative change of Young's modulus, AE/E, with magnetic field, H, in ferromagnetic nickel-copper alloys (A-alloys). Fig. 3 Relative change of Young's modulus, JE/E, with weak magnetic field, H, in ferromagne tic nickel-copper alloys (A-alloys). Fig. 5 Relative change of Young's modulus, E/E, with external magnetic field, Hex, in ferro magnetic nickel-copper alloys (B-alloys).
Fig. 6 Relative change of Young's modulus, E/E, with weal, external magnetic field, Hex, in ferromagnetic nickel-copper alloys (B-alloys). modulus,(de/e)o, and the composition (in weight percent) in ferromagnetic Fig. 7 Relation between the saturation value of the relative chanye of Young's nickel-copper alloys (A- and B-alloys). Table 3 Tabulation of miscellaneous measured and, calculated data for ferromagnetic nickelcopper alloys (A- and B-alloys). (4E/E). denotes the saturation value of the change of Young's modulus with magnetization, relative. to that in the non-magnetized state, H.the intensity of magnetic field where the change of the modulus saturates, (de/e)_the negative minimum value of the relative change of the modulus, (I/h)_ the reduced magnetization at which (JE,/F_)_ is attained, p the density, E Young's modulus in the non-magnetized state, 1, the saturation magnetization, KO the initial susceptibility, and A,the saturation magnetostriction (measured by Masumoto, Shirakawa and Kobayashi).
Fig. 3 Relative change of Young's modulus, E/E, with reduced magnetzation, I/I, in ferromagnetic nickel copper alloys (A-alloys). Fig. 9 Relation between Young's modulus in the non-magnetized state, E, and the composition(in weight percent) in ferromagnetic nickel-copper alloys (A- and B-alloys). Experimental data obtained by Nishiyama, Nakamura, and Aoyama and Fukuroi are also shown.
Fig. 11 Relation between the initial susceptbility, K0.and the composition (in weight percent), in ferromagnetic nickel-copper alloys (A- and B-alloys). Table 4 Parallel relation between the saturation value of the relative change of Young's modulus with magnetization, ( E/E), and the Initial susceptibility, up, in nickel-copper alloys of different origins.