The amount of retained austenite (γ_R) in high-cardon alloy steels (0.99% C-2.86% Cr and 1.00% C-4.99% Ni) under application of stresses (tension, compression and bending) while the steels are cooling has been studied as a function of the kind of stress and the temperature of loading. The principal results may be summarized as follows. (1) When the steels are transformed under application of stress, the amount of γ_R was increased by tensile stress and decreased by compressive stress. These findings are quite contrary to the expectation of the accepted opinion that the martensite transformation is improved by shear stress and normal tensile stress but is inhibited by normal compressive stress. (2) It was observed that the steels which were loaded at the range only above the Ms temperature indicated the same effect as in (1) above i.e. γ_R was increased by tension and decreased by compression. This is contradictory to the opinion that work hardening causes mechanical stabilization of austenite, for if we follow this opinion γ_R must be increased by compressive stress, as much as by tensile stress. (3) At the range below Tc temperature at which the effect of stress begins, the amount of γ_R was determined by the width of the temperature range in which the load was applied, i.e. a temporary application of stress or deformation has little effect on γ_R. Therefore it seems that the grade of stabilization of austenite in the present work is little affected by deformation but mainly by the stress itself during cooling. (4) Tc temperature of compressive stress was higher about 50∼100°C more than Tc of tensile stress. In medium carbon alloy steel (0.58% C-4.02% Ni), the amount of γ_R was not changed by the tensile stress but decreased remarkably by the compressive stress.

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The equilibrium composition of the solid phase differs in general from that of the liquid phase, and segregation may occur which the composition of the solid phase formed at different times differs from the bulk compositions.
In the case of the β→α transformation in nickel aluminium bronze castings, as well as in the solidification of solid solution, the composition of the coexisting β and α phase have to change continuously. But the change requires diffusion, which at ideal condition remains incomplete in α phase, since the diffusion rate in α phase are comparatively low. So non-equilibrium eutectoid remains in the alloy containing 9 to 10% aluminium and 5% each of nickel and iron.
Theoretical approach has been also made for the degree of segregation which depends on the factors of the nucleation rate of the α phase.
It has been shown that under slow cooling conditions significant segregation can be expected if the nucleation rate is low.

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It has been reported preiviously that an ordering reaction, the β→β₁ transformation, occurs first, followed by a martensitic transformation, β₁→β′, on rapid cooling from the β region in Cu-Al binary alloys. The possibility of this transformation process has also been observed in the case of isothermal transformation by means of dilatometric, electric resistance, and specific heat measurements. In order to determine the crystal structure of the β′ martensite with ordered configuration, a powdered specimen containing 24.06 at% Al close to an eutectoid composition was water-quenched from 950°C, and then analyzed by using the diffraction pattern obtained by use of an X-ray diffractometer.
The experiments showed the following results, (1) The superlattice lines observed in the diffraction pattern of β′ martensite has proved that the β₁→β′ transformation retains the Cu₃Al type ordering configuration, Cu₃Al type, when rapidly cooled. (2) The crystal structure of the β′ martensite is a distorted hexagonal closepacked structure, in which the (0001) direction makes an angle of about 3^° to the normal (0001) plane. The results obtained have been discussed with the martensitic transformations of Cu-Al, Cu-Zn, and Cu-Sn binary alloys and the similarity of the crystal structure and habit plane.

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The directional order induced by magnetic anneal in a ferromagnetic face-centered cubic binary solid solution and its correlation with an ordinary AB₃ superlattice are calculated by the quasi-chemical method using quadruplets approximation. The anisotropic long-range order parmeters and sixty four parameters representing the numbers of different quadruplets are introduced to describe both the directional and ordinary order, and their equilibrium values in the magnetically annealed state are calculated. It is shown how the formations of short-range and long-range orders during magnetic anneal depress the occurrence of the directional order and thus of the additional uniaxial ferromagnetic anisotropy. The change caused by ordering in the directional property of the induced ferromagnetic anisotropy is indicated. The results obtained can explain the observed irregular behavior of the induced ferromagnetic anisotropy in the magnetically annealed Ni₃Fe single crystal.

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The effect of the short-range order or of the clustering of like atoms on the magnetically induced directional order is calculated, by the quasi-chemical method using the quadruplets approximation, for the entire concentration range of face-centered cubic binary solid solution systems. Sixteen parameters denoting the numbers of different quadruplets are introduced in order to describe the short-range atomic configuration. Their equilibrium values under magnetic anneal are calculated and hence the induced ferromagnetic anisotropy energy associated with directional order is determined. The results of the numerical calculation of the induced anisotropy are compared with available experimental data for Ni-Fe and Ni-Co alloys.

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The niobium-carbon system has been investigated by melting point measurements, X-ray analyses and microscopic examinations. An equilibrium diagram up to 63.5 atomic percent carbon was constructed as shown in Fig. 2. The limit of carbon solubility in niobium (α) phase lies at about 2 atomic percent at 2000°C and it decreases abruptly as the temperature decreases. The Nb₂C (β) phase has a very narrow range of homogeneity and the NbC (γ) phase exists in a wide composition range from 41 to 50 atomic percent arbon below 1400°C. Three non-variant reactions in this system were determined as follows.
(Remark: Graphics omitted.)

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Ferromagnetic domain patterns have been observed, using the powder pattern technique, on single crystals of Ni-Co alloys containing 4, 6, 12, 18, 20, 68, 69, and 70% Co as well as on cobalt ingots as solidified slowly and then variously heat-treated. Annealed 4∼20% Co-Ni single crystals revealed maze patterns even after severe electrolytic polishing and proper domain patterns only after quite severe electrolytic polishing. Analysis of the observed domain patterns indicates that the first magnetocrystalline anisotropy constant, K₁, is positive for 4∼18% Co, while it is negative for 20% Co. A domain pattern observed on a locally strained (100) surface of a 12% Co-Ni single crystal, which consists of 180° domain walls radiating from the loaded point, shows that the internal stress in the surface layer takes a distribution concentric around the loaded point.
68% Co-Ni single crystals revealed domain patterns characteristic to f.c.c. crystals with K₁<0, and, in 69% Co-Ni single crystals, ε (h.c.p.) phase crystals were seen as layers parallel to {111} planes, indicating that the boundary of the γ (f.c.c.) phase is located at 68% Co. Further, on {110} surfaces of 69% Co-Ni single crystals, traces of ε-phase crystals were seen as bands parallel to two ⟨112⟩ and one ⟨110⟩ directions. The behavior of 180° domain walls in the matrix γ-phase crystal when they meet with ε-phase crystal bands shows that the direction of easy magnetization in ε-phase Ni-Co alloys is the [0001] direction, irrespective of the compositon, just as in cobalt.
Finally, cobalt ingots, which were solidified slowly from the melt and then cooled very slowly through the γ→ε transformation temperature, are seen to be finely divided by numerous ε-phase crystal bands, among which there exist γ-phase crystal regions of parallelogram and triangular shapes. A similar structure is observed in cobalt ingots as quenched in hot water after slow solidification, although the proportion of γ-phase in quenched ingots is larger than in slowly cooled ones.

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On the anodic passivation of metals, two different processes, (A) precipitation from a super-saturated solution and (B) direct reaction between a metal and solution, have been previously considered for the anodic formation of passive oxide film. Both of these mechanisms were criticized from the kinetic point of view to conclude that both are negative for the formation of a compact pore-free oxide film. Then, in order to clarify the passivation process, many electrochemical investigations were made on the active-passive transition of nickel in sulfuric acid solutions. It was concluded that the passive film is formed in accordance with the following successive reaction, Ni+OH⁻→NiOH⁺+2e, 3NiOH⁺+OH⁻→Ni₃O₄+4H⁺+2e. The critical potential beyond which such an oxide formation takes place is calculated to be equal to the Flade potential, if the concentration of NiOH⁺ ion in the vicinity of the surface has a saturated value corresponding to the solubility product of NiO. A generalized theory for the passivation of metals in corrosive solution can be proposed. The compact pore-free passivating film can be formed only by an anodic reaction of soluble metal ion on the surface of metals, and so the passive film having an ability to protect the metals against dissolution in corrosive solutions must be composed with an oxide film of higher valency than the ionic valency of the soluble metal ion in active dissolution.

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To better understand the electrochemical mechanism of metallographic etching, the effect of potential on the etching figure has been studied by using a potentiostat. The microstructural figures obtained by potentiostatic etching methods and ordinary etching methods were compared to each other using 18-12 Cr-Ni-Mo-Si duplex cast steel. The steel was heat-treated either by quench-annealing or by sigmatizing and etched in a 1 N Sulphuric Acid aqueous solution containing 0.01% ammonium-thiocyanate at constant potentials controlled by a potentiostat. It was found that a certain kind of phase can be selectively etched at an appreciable rate by controlling the potential in both active and overpassive potential ranges. In the active potential range, the optimum potential for etching shifted to the less noble direction with the increase of Cr content of structural phase. Thus, differential etching for δ-, γ^′- and γ-phases can be performed at potential ranges of −0.40∼−0.30, −0.30∼−0.21 and −0.25∼−0.21 V (V. v.s. S.C.E.), respectively. σ-phase was not attacked but appeared in relief brightly in the active state. In the overpassive region, the etching rate increased with the increase of Cr content of phase. σ-phase can be well differentiated at the potential region of the socalled 2nd passivity which appears above ca. +1.4V. because of the remarkable difference between the dissolution rate of σ-phase and that of the other phases. It was found that chemical and electrolytic etchings are performed at a certain constant potential controlled by various factors and then the principle of those ordinally used etchings is considered to be the same as that of the potentiostatic etching.

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The clustering of solute atoms in an Al-Cu 4% alloy, which was water-quenched or air-cooled from the solution temperature and elongated to various amounts in liquid nitrogen, was followed by measurements of the electric resistivity.
The results show that the initial rate of clustering is enhanced by plastic deformation after water-quenching and considerably after air-cooling. However the rate decreases more rapidly with aging in a deformed specimen than in an nondeformed specimen. The activation energies obtained from the initial rate of resistivity increase were about the same value, 0.5±0.03 eV, for a water-quenched specimen without deformation as well as an air-cooled and about 5% elongated specimen. These results are interpreted by the excess concentration of vacancies and the increase of dislocatiion density produced by plastic deformation.

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Electrolytic isolation of carbide, sulfide and phosphide in white cast iron and the distribution of sulfur and phosphorus were studied.
Specimens employed were produced in the following way; calculated amounts of pure iron, electrolytic iron, pure carbon, ferrous sulfide and phosphor iron were charged and melted in a high frequency furnace and cast in iron moulds 7 mm in diameter.
The specimens were electrolyzed in 0.2 N hydrochloric acid solution or a sodium citrate mixed solution. In order to separate carbide and sulfide inclusions from residue obtained by electrolysis, magnetic separator and ultrasonic wave were applied. Sulfur and phosphorus in these structures were determined by chemical analysis. And the following results were obtained: (1) The concentration ratios (S or P% in Carbide/S or P% in white cast iron) of sulfur and phosphorus were 2.2 and 1.4, respectively.
(2) In order to separate sulfide inclusions from residue obtained by electrolysis, supersonic treatment before magnetic separation was effective.
(3) When the Mn/S of the white cast iron increased, the amount of sulfide inclusions dissolved throughout the electrolytic isolation increased rapidly.
(4) The residue obtained by iodine treatment was observed by X-ray diffraction. The diagram obtained was similar to that of Fe P.

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Transmission electron miroscopy of dislocation arrangements in extended α-brass was carried out. While dislocation arrays piling up against various obstacles were observed at small strain, dislocations came to tangle with each other resulting in complex features with increasing amounts of deformation. Continuations of slips across grain boundaries and twin boundaries were also observed.
These results are discussed in connection with work-hardening mechanisms at various stages and the mechanism of deformation propagation in polycrystals. It is also shown that the results obtained in the present investigation agree well with the ones gained by etch pit technique.

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