In order to prepare large single crystal sheets from an electrolytic iron, the effect of roll textures on the growth of large crystals by a strain-anneal technique has been investigated. The results show that the preferred orientation of large grains grown by the strain-anneal method is approximately the same as the roll texture, and that the large crystals free from island grains left on the sheet surface has the (100) plane in the sheet surface. It is necessary to prepare a sharp (100) [011] roll texture for the growth of large crystals (1∼2 mm in thickness and about 45×300 mm² in the sheet surface) with the (100) [011] orientation by the strain-anneal method. This roll texture was produced by cross-rolling in the final stage of rolling process. Attempts to grow crystals with other orientations ended in a failure.

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Structure and distribution of chemically reactive areas have been studied on electrodeposited polycrystalline nickel having (211), (210) and (110) preferred orientations by means of electron microscopy. These characteristic preferred orientations occur in nickel specimens more than a few μ in thickness electrodeposited on mechanically polished copper substrates. Special procedures have been devised in order to directly observe the structures of thin top layers of the thick deposits having the preferred orientations by means of transmission electron microscopy.
A large number of hillocks with the (\bar111) twins are formed in an electrodeposited nickel with the (211) orientation. This result was previously obtained by the author by means of reflection electron diffraction and electron microscopy using replicas, and has been confirmed in the present study. It has also been found that twin and grain boundaries in these deposits are chemically reactive and dissolved initially in a corrosive solution. In an electrodeposited nickel with the (210) orientation, twin boundaries and stacking faults are dissolved during immersion in the corrosive solution. In an electrodeposited nickel with the (110) orientation, the twinning is seldom formed, and the deposit shows no areas remarkable in chemical reactivity except grain boundaries. The electrodeposited nickel with the (211) orientation prepared by the present electrodepositing conditions appears to be more chemically reactive than the deposits having other orientations, because a high density of chemically reactive crystal defects is found in the former.

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Load-elongation curves of single crystals of Cu–Al solid solutions of 1.2, 2.3, 6.5, 10.5 and 14.2 at % aluminum are measured at room temperature, the liquid nitrogen temperature and the liquid helium temperature. Serrations are observed in the load-elongation curves in the stages I and II. The increase of yield stress on annealing at 200°C and the dependence of yield stress and yield drop on the crystallographic orientation of the tensile axis are also observed. From these experimental results, the hardening of Cu–Al solid solutions is concluded to be due to a source hardening mechanism. The “pole mechanism” for glide dislocations is considered as the origin of the serrations in the stage I . Annealing effects on several work-hardening parameters are also observed.

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It has been known experimentally that oxygen contents in cast iron products often show remarkably scattering values even in a same kind of products, the unexpectedly high or low values of which are hardly comparable with those evaluated from previous works on the equilibrium between carbon and oxygen in carbon-saturated molten iron. This can be attributed to the difficulty in determining the oxygen content in cast iron owing to the presence of graphite. In order to examine the equilibrium of carbon and oxygen in carbon-saturated molten iron, experiments were carried out in the graphite crucible under CO atmosphere by means of a sampling method established by the present authors: The method consisted of sucking white iron samples from the melt by a thin silica tube and immersion into mercury. Analysis of oxygen was carried out by measuring the electric conductivity in argon-carrier fusion which has the accuracy of less than ±2 p.p.m. within the range of less than the 10 p.p.m. oxygen content.
The results obtained are as follows:
(1) The solubility of carbon in molten iron will be expressed by
C%=1.33+2.59×10⁻³×t°C.
(2) Relations between carbon and oxygen in carbon-saturated molten iron will be
C(g)+O=CO, logK₄(=P_CO2⁄P_CO×O)=9,018⁄T−6.045,
logK₃(=P_CO⁄O)=613⁄T+2.775, C+O=CO (carbon saturation),
O+CO=CO₂ (carbon saturation), logK₇(=P_CO⁄C%×O%)=1.239⁄T+1.711.
(3) The activity coefficient of carbon and oxygen in carbon-saturated molten iron will be
logf_c=−847⁄T+2.055−log{1.33+2.59×10⁻³(T−273)},
logf_c=300⁄T−1.283.
(4) The oxygen content of carbon-saturated molten iron is extremely low. Consequently, the equilibrium product (C).(O) does not show a large value, and the activity coefficient of oxygen obtained is not an extremely small value.
(5) To determine the exact oxygen content in carbon-saturated molten iron it is essential to prevent graphite from precipitation in samples as much as possible. Furthormore it is necessary to establish an analytical method which is possible to determine an extremely low oxygen content up to the level of 0.0001%.

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The motion of defects in hydrogen-treated Johnson-Matthey pure iron strained at −196°C has been studied in the temperature range between −120° and 260°C using electrical resistivity measurement. There appears to be five stages of recovery; the second and the third ones centred at −130°C and −60°C, with activation energies of 0.3 and 0.5 eV, and attributed to the motion of di-interstitials and of divacancies, respectively. The time law of the decay of the above-mentioned point defects are best interpreted in terms of the attraction model by the parallel dislocation group. The stage V recovery occurs above 80°C with a continuously increasing activation energy from 0.9 to 1.8 eV in the temperature range studied (80∼260°C). This stage is attributed to the recovery of dislocations, depending on the internal stress. Defect resistivities at −196°C are estimated as follows: ρ_p=24×10⁻⁶ Ωcm/at %, for point defects, and ρ_d=8×10⁻¹⁹ Ωcm/cm⁻² for dislocations.

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In order to investigate the mechanism of fatigue at elevated temperatures, the process of fatigue in annealed specimens of 99.99% aluminium and lead has been observed microscopically at testing temperatures from 0.5 to 0.85 Tm°K under reversed torsional and bending stresses, where Tm is the melting point.
The results observed at the early stage of the high-temperature fatigue are summarized as follows:
(1) The grain boundaries move in parallel with the maximum shear stress direction of the specimen axis.
(2) Accordingly, the grain boundaries of polycrystals are gradually migrated orthogonally in the maximum shear stress direction under reversed stress.
(3) The characteristics peculiar to the above grain boundary migration are observed not only on the specimen surface but also in its interior.
The reasons for the above phenomena are discussed in connection with the release of the stored energy resulting from the repeated boundary sliding, the occurrence of slips in the matrix almost in parallel with the maximum shear stress direction, and a smaller amount of the vacancy flow than that of creep.

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In order to study the high temperature fatigue mechanism in pure metals, an apparatus containing a microscopic cine-camera combined with the fatigue machine was devised for continuous and direct observations of the specimen surface during the fatigue in vacuum at elevated temperatures. A Xenon flash tube was used for illuminating the specimen surface. It was triggered synchronizingly at the same phase of deformation of the specimen. Each cut of the fatigue process was photographed in the time-lapse sequences and also taken in motion picture if necessary.
The time-lapse technique was effective in analyzing the fatigue mechanism at elevated temperatures. The results obtained in the specimens of pure aluminum and lead under reversed bending and torsional stresses over the temperature range 0.5 to 0.85 Tm°K are as follows:
(1) The grain boundaries move in a way that they are in parallel with the maximum shear stress direction of the specimen axis. Accordingly, grain boundaries of polycrystals are gradually aligned orthogonally with the maximum shear stress direction during the fatigue.
(2) Subgrains generate in coarsed grains or in single crystals under reversed stress, and their grain boundaries are aligned orthogonally as in the above case.
(3) The surface markings consisting of a series of sharp valleys and peaks due to the deformation band are found in the specimen fatigued at about 0.5 Tm°K under reversed bending.
(4) These continuous observations for the fatigue process serve to support the high-temperature fatigue mechanism which has been described in the previous reports.

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The electromotive force method was applied to the determination of thermodynamic properties of the liquid silver-indium system. The electrode potentials of the concentration cells of the following type were measured in the temperature range from 1000° to 1200°K;
In(liquid)/InI in NaI+KI/In-Ag (liquid).
The partial and integral values of the excess enthalpy, excess free energy and excess entropy of this system were calculated from the experimental results. The experimental results were discussed in terms of the existing solution theories.

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The extents of grain-boundary diffusion of mercury into 70/30 brass and of 3% Zn amalgam into aluminium were evaluated by a simple tensile-test. Without knowing the penetration depth, the data on the diffusion-treated specimens can be analyzed by the equation
(Remark: Graphics omitted.)
where ΔF is the difference in fracture load before and after the diffusion treatment, F₀ is the fracture load before the treatment, a and b are the breadth and thickness of the specimen, k is the parameter for the diffusion path, D is the diffusion coefficient, and t is the contact time. The diffusion equations obtained are as follows:
(Remark: Graphics omitted.)
The diffusion rate at room temperature, assessed from the results at elevated temperatures, is extremely small and the role of diffusion in the degree of embrittlement is not significant in these systems.

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The partial phase diagram in the Th-C system between pure Th and ThC was studied by metallographic and X-ray techniques and by measurements of electrical resistivity in quenched and slow cooled Th-C alloys. The peritectic point of the reaction, liq.+ThC \ ightleftarrows α-Th, was found at 16 at%C and about 1875°C and the peritectic composition of ThC was 33 at%C. The eutectic reaction occurred at 1650°C and its composition of α-Th and β-Th was 6.5 and <0.5 at%C, respectively. The α\ ightleftarrowsβ transformation temperature rose gradually with the carbon content up to 2.3 at%C and rose rapidly between the compositions of 2.3 and 3.7 at%C. The phase boundaries of α/ThC+α, ThC+α/ThC, ThC/ThC+ThC₂ and liq.+ThC/ThC were also established.

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This study has been carried out in order to clarify the interactions between metals and molten salts. As one of the basic studies on the mechanism of reaction between metals and molten salts, an investigation on the dissolution of solid copper in molten bismuth trichloride under static and isothermal conditions in the temperature range from 240°C to 440°C is reported in this paper. The reaction products were subjected to chemical and thermal analysis. In this system, when reacted for a sufficiently long time at each temperature, the reaction was promoted according to the equation
3Cu+BiCl₃=3CuCl+Bi,
and rapidly attained the equilibrium above 400°C. In the early stage of the reaction Bi produced was dissolved in molten BiCl₃, and therefore the amount of metallic bismuth increased rather slowly compared with that of CuCl produced. When the dissolution process was investigated at 300°C and 420°C with the lapse of time, it was known that CuCl₂ was also produced in the early stage of the reaction but CuCl₂ was rapidly reduced into CuCl with the advance of the reaction.

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The dynamic tensile tests of pure iron and low carbon steel at a strain rate of 30/sec were performed at room temperature and −78°C. The results of measurements of the yield and the flow stress were analyzed on the basis of the Petch equation and discussed with emphasis on the effects of the impurity amount and of the amount of prestrain on the strain rate and the temperature dependence of frictional stress. It was found that the strain rate and temperature dependence of frictional stress was neither influenced by the presence of interstitial elements nor affected by the amount of prestrain. Therefore it was concluded that the strongly thermally activated motion of the dislocations is the process of surmounting the lattice intrinsic potential barrier such as the Peierls potential, which was confirmed by the small value of the activation volume.

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