The dynamical characteristics of the iron-aluminium alloys containing from 6.36 to 14.38 percent aluminium has been measured by the bridge method in the various fields of 5, 10, 15 and 20 Oersteds. It has been found that two curves representing the relations of the magnetostrictive activity and the sound velocity in a field of 10 Oersteds to the concentration have respectively a maximum and a minimum portions in the range of about from 12.2 to 13.4 percent aluminium contents; this range almost coincides with that of the maximum portion (11.5_??_13.2% Al) in the case of statical magnetostriction. The largest value of magnetostrictive activity is 0.058 of 13.19 percent aluminium alloy and the souud velocities in the minimum portion range from 4500 to 4540m/sec. A small addition of nickel to these alloys fairly increases their magnetostrictive activities. And the electro-acoustic efficiencies of these alloys, calculated with Dr. Kobayashi's formula are of the same order as that of nickel, being nearly 100 percent. So these alloys may be used as magnetostriction oscillatror instead of nickel.

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If we assume a magnetic domain has one dislocation line, the angle between the direction of the magnetic field and the magnetic moment close to the dislocation becomes α=α₀l-√_7y its mean being nearly √_1.8. Then the term B/H appearing in the magnetization formula will be explained as the effect of dislocation, ie. B=1.8π/4i², l being the lniear dimension of a magnetic domain. If we take 10^-5 erg/cm as C for Ni, l will be nearly 3×14^-4cm. The spontaneous magnetization at the zeor magnetic field is influenced by dislocations and J's=Js(_??_1-π/₄nlC/_|K|) The magnetic field needed to accomplish discontniuous magnetization becomes about 0.05 Oe and coincides to the value obtained by Bozorth in permalloy. Also, the coefficient 1/3 of the term Js²/3XaH of the magnetization formula in a strong magnetic field isexplained as the effect of dislocation.

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In the previous paper, (this jour.), the relative positions of energy level, E₁, E₂, E₃ and E₄, in Cu, were determined from X-ray spectrum. In the present work, the above results were compared with the photoelectric effects and the light absorption in its thin film, and the results are as shown in the following table; similar results had previously been already obtained for Zn.
_??_
From these results it was inferred that the threshold energies in the photoelectric effect for (100) and for (111), of Cu, are equal to the energy distances E₂-E₄ and E₂-E₃, respectively. Further, the result above inferred, was combined to the experimental result obtained by T. Fukuroi, saying that the threshold energy of fhe photoconductive effect of the thin film of metals, Zn, Cd and Hg, is equal to that of the ordinary photoelectric effect for the same element, it was inferred that, the high resistivity of the thin film of metals comes from the fact that, in such a film, the levels, E₃ and E₄ are rarely occupied by electrons while E₁ and E₂, constantly; accordingly E₃ and E₄ are conduction levels but not E₁ and E₂. Furthermore, it was taken as that, the thin surface layer of bulk mass of a metal has a similar electronic structure as above described. So, when the exciting energy amounts to its threshold value, the electron in E₂ is elevated to E₃ or E₄ in both cases; and there occcurs electric conduction in the thin film, and photoelectron emission, from the surface layer of the bulk mass, of the metal. Therefor it was concluded that the mechanism of the releasing of electron from the level, E₃ or E₄, is the same in both cases, and so also in the case of electric conduction within the bulk mass of metals, asserting that, it is no other than the authoionization which is well observed in free atoms and in free molecules. Accordingly that within the bulk mass of Cu, valency electrons are in E₁, E₂, E₃, and E₄; but in its thin surface layer, E₃, E₄ are rarely and E₁, E₂ constantly, occupied by electrons.

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An expression for enormously large internal tension or pressure accompanying the transformation of a substance has been obtained, that is,
(1) p=1/₂Kδv/_v/ςλ
where K is the bulk modulus of elasticity, δv/_v the total change of volume during transformation, ς the density and λ the heat of transformation. If this expression is combined with Clausius-Clapeyron's equation
ΔT=Tδv/_vp/ςλ
for the depression or elevation Δp of the transformation point, we obtain
(2) ΔT=0.355KT(δv/_v)²/ςλ
Thus ΔT can be calculated from known data for K, T, δv/_v, ς, λ The comparison between the theoretical and observed values has been made in the case of iron, iron-nickel and manganese alloys; the depression of the freezing point of water has also been calculated and compared with the observed value. In all these cases the agreement between the theoretical and observed values is satisfactory Thus two expressions (1) and (2) above given are confirmed by experiments.

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Fe-Ni alloys have been cooled from 1050° to room, ice water or liquid air temperatures with various speeds and in each cases the stress restored in them have been measured by the method of dissolving off one side of the specimen layer by layer with chemicals and measuring the change of length of the latter precisely. In Fe-Ni alloys the diffusion proceeds very slowly and the austenite easily supercools below the curve GB in Fig. I and transforms into alpha solution on passing the curve GA without changing its composition. Results obtained are as follows. (1) Stress is restored in the specimen in all cases even if the specimen is very slowly coooled provided that the lattice transformation has been followed. The maximum stress lies on the surface of the specimen and it is always in tension, the magnitude of which increases as the rate of cooling increases. (2) The cooling stress (compressive on the surface) ormed before the transformasion is released on the transformation as the latter is a rearrangment of he crystal lattice. (Fig. 3) (3) The residual stress on the surface increases as the content of Ni_??_in he alloy increases at first and attains a maximum and then decreases. The Ni content corresponding to the maximum is changed by the temperature of the quenching medium. (Figs. 5 and 7).

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The residual stress restored in the specimens after variously heat-treated was reported in previous papers. The changes in dimensions and shapes of the same specimens are explained in the present paper. The specimens are Fe-Ni alloys with various Ni contents. The results obtained are as follows: In the course of the quick cooling, the prismatic specimen bends by the cooling stress before Ar'', and the shape of the specimen thus changed remains almost unaltered when it undergoes Ar'' transformation, while the cooling stress before Ar'' is released by the Ar''.

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It si well known that the lattice transformation can not be finished at the point even when it keeps the same temperature, but it follows on ranges of a few hundred degrees of temperature. There exists a proper temperature interval of lattice transformation in the fixed concentration of alloys being independent of the cooling rate in the case when it is not extraordinarily fast or slow. A sort of strain austenite crystal, accompanied by a partial transformation in retained makes resistances against the following changes. But when temperature decreases, the excess of free energy stored in austenite by super cooling, supplies sufficient energy to overcome the resistance following transformation At that time the transformation is begun spontaneously again.
In accordance with the fact that the crystallographic process of gitter transformation more resembles the dynamical gliding, we can assume a certain connecting relation between free energy difference for transformation and mechanical energy for plastic gliding. From this relation we evaluatedd the aependence amounts of transformation on temperature through correspondence between phenomenon of the temperature interval and the strain hardening in plastic deformation. Calculated values for the Fe-Ni alloy containing 20% Ni agree with the obseration.

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The authors investigated the effect of manganese 0.6_??_1.2% on the temper-brittleness of silicon-manganese-chromium steel. As the result of this investigation, there are ascertained that the “First and Second Temper-brittleness” increase remarkably with manganese content. It is observed that the maximum rate of temper-brittleness occurs at tempering temperature of 600_??_650°, and that there is little variation by the cooling velocity after tempering and manganese content.

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The authors investigated the effect of 0.6_??_1.2% chromium on the temper-brittleness of silicon-manganese-chromium steel. As the result of this investigation, the “First Temper-Brittleness” is observed at above 0.80% chromium content, while the “Second Temper-Brittleness” increases remarkably with chromium content. In the case of 0.8_??_1.2% chromium content, the rate of temper-brittleness is very large at tempering temperature of 600°.

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In high speed steel generally grain growth occurs owing to high quenching temperature; the temperature causing abnormal grain growth varies due to heat treatment before quenching. If the temperature giving strain before quenching rises to more than 1200°, the abnormal grain growth occurs when the quenching temperature is equal to or higher than the above temperature, but this steel becomes of smaller grain and is more superior in the cutting durability than the larger one; but the cutting durability cannot be conceived only by the grain size; the history of the heating works must be considered.

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Cooling and solidification of sand casting were investigated by measuring the temperature of metal and sand at several points and the cooling effect of sand is discussed. The results are as follows: 1. Dried sand conducts heat of metal by expansion of air involved in it additional to its own conduction. 2. Green sand does the same, but still more by vaporization of moisture and its expansion. 3. Air and moisture in sand convey heat of metal by their expansion without any convection. 4. High casting temperature gains the solidification time and much humidity in sand loses it. 5. Cooling of metal is calculated and an experimental formula of solidification time is introduced.

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