Internal Stress due to Quenching in Cylindrical Steel Ingots

The relations between residual internal stresses due to quenching and quenching temperature for large cylindrical steel ingots are obtained on the basis of the theory of elasticity, by taking into acount the thermal stresses and the plastic flows of steel during their heat treatment. The results thus obtained are summarized in Fig. 9

On the Collective Electron Model of Ferromagnetism

The spontaneous magnetization of the ferromagnetic substance was discussed on the basis of the collectiive electron model, the result of which was applicable to the case of an intrinsic semi-conductor. Sudden disappearance of spontaneous magnetization in some kinds of ferromagnetic semi-conductors was expected form the present theory This result coinsided with the experimental data on CrS by Haraldsen and Neuber

On the Changes of Electrical Properties in Cold-Worked Metal

The increase in electrical resistance of metals due to cold-work was discussed taking into account the perturbing potential due to the edge dislocation caused by the said mechanical treatment. The method of calculating the electric conductivity was based on Peterson and Nordheim\u27s assumption for the perturbing potential. An estimation of thermoelectric power due to cold-work was made from the same point of view. A criticism was given for the theories by Koehler and Machenzie-Sondheimer. The results obtained showed somewhat smaller value than the results of the above-mentioned authors

An Automatically Recording Magnetic Balance

A newly designed magnetic balance for plotting automatically the magnetization-tempera-ture curves of the magnetic substances of the ferromagnetic and other types is introduced. The essential part of this instrument consists of the automatic compensensation of the unbalance of the above mentioned balance due to a force acting on the sample. The change of susceptibility due to the rise or fall of the temperature of the specimen can be obtained from the chart in which the electric current for the above-mentioned compensation is recorded. The new apparatus is useful in magnetic analysis of various kinds of magnetic substances

A Machanism of Spin-Lattice Relaxation in Ferromagnetic Substances

A mechanism of the line broadening in a ferromagnetic resonance absorption was explained on the basis of the relaxation of spin orientation due to the interaction between spin wave and phonon fields in the crystal lattice. It was theoretically found that, at low temperatures, the line width was roughly proportional to 3/2th power of the absolute temperature. The experimental relationship between the line width and the temperature was explained by the theory. It was also found by this consideration that the relaxation time of spin reorientation was greatly influenced by the mean free path of Debye wave in the crystal

Attenuation of the Ultrasonic Waves in Metals. I : Aluminium

Attenuation coefficients of longitudinal ultrasonic waves in aluminium were measured by pulsed ultrasonic waves at the frequencies ranging from 2 to 25 megacycles per second. Specimens were annealed several times successively at the temperatures below its melting point to promote the growth of crystal grain from 0.2 to 2 mm. Some corrections on the measured values of attenuation were carried out to eliminate the errors arising from propagation characteristics of the sound waves in the specimens. General feature of the change of attenuation coefficients with respect to frequency and grain sizes were as follows : (1) when the grain diameter was smaller than wave length of sound, the slope of attenuation versus frequency curve increased with grain size ; (2) when grain diameters were greater, the slope became very small ; (3) at the intermediate size of grain gradual variation of the slope appeared between lower and higher range of wave length, From these characters of ultrasonic attenuation in polycrystalline metals, several remarks for ultrasonic flaw inspection in metals and alloys were obtained

Formation of Superlattice in Face-Centered Cudic Lattice with a Special Reference to the Copper-Platinum System

Based on the notion that, for the formation of certain types of superlattices in face-centered cubic alloys, the second neighbor interaction becomes appreciable, the formation of superlattice in copper-platinum system was studied, and the ordering energy in such a formation was obtained from the viewpoint of electron theory. The results could interpret both quantitatively and qualitatively various results of many experiments concerning this binary system

Attenuation of the Ultrasonic Waves in Metals. II : Stainless Steel

Ultrasonic attenuation coefficients of stainless steel with various grain sizes were measured by pulse method at the frequencies ranging from 0.5 to 6 Mc/s. The stainless steel used was of austenite structure containing about 19 per cent of chromium and 10 per cent of nickel. It was found that the attenuation coefficient increased remarkably with the frequency, and that the increase was more rapidly with increasing size of crystal grains. The nature of such an attenuation behaviour was explained by assuming that the travelling ultrasonic waves are scattered by the austenite crystal grains in accordance with the Rayleigh\u27s law

The Change of Curie Temperature of Ordered Au_4Mn and the Indium Heusler Alloy by Hydrostatic Pressure

The change of Curie point by the application of hydrostatic pressure of 3 katm. to the Indium Heusler alloy as well as the intermetallic compound Au_4Mn was measured. It was found that the rate of change took positive value 1.5×10^ and 2.7×10^ deg/kg/cm^2 for Heusler alloy and Au_4Mn respectively. It was also elucidated that the change of absolute saturation of magnetization for both alloys was negative, -2.1×10^ and -7.2×10^ cm^2/dyne respectively