The solubility of hydrogen under high hydrogen pressure was calculated for nine metals, Al, Mo, W, Fe, Ni, Pt, Cu, Ag and Au, by using the equation of state of fluid hydrogen at high pressures and solubility data at normal pressure. It is found that the solubility is enhanced substantially as the dissolution process changes from endothermic to exothermic at high hydrogen pressures.
Effects of the elastic interaction between dissolved hydrogen atoms are also examined briefly.

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The morphology of the 2H phase in a Ni₆₇Cu₈Sn₂₅ alloy that was treated by different cooling rates was studied by means of electron microscopy. The transformation from the high temperature DO₃-type cubic phase to the 2H(β-Cu₃Ti)-type orthorhombic structure was found to be massive in the case of furnace cooling and martensitic in the case of quenching. In the massive 2H phase of the furnace cooled specimen, defects such as stacking faults, planar defects terminated by dislocations and stacking faults with antiphase boundaries were observed. A few plates of 2H structure were also observed as growth faults in a massive grain. Some of such plates were (121)_2H twins. If the cooling rate of specimen was decreased, the morphology of the 2H phase was considered to change gradually from the martensite-like structure to the massive one due to the migration of interfaces.

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The magnetic field-induced martensitic transformation in an Fe-31.7 at%Ni alloy has been studied by means of magnetic measurements and optical and electron microscopies, pulsed magnetic field being applied at the Ultra High Magnetic Field Laboratory, Osaka University. As a result, it is shown that there exists a critical strength of magnetic field to induce the martensitic transformation at a given temperature above M_s. The critical strength increases with increasing temperature difference from M_s, ΔT, and those plotted as a function of ΔT lie on two straight lines bent at a temperature of ΔT=22 K. However, the martensitic transformation does not start in the time when the magnetic field has reached the critical strength, but is delayed. The delay time is dependent on ΔT alone and on both ΔT and H in the temperature ranges above and below ΔT=22 K, respectively. The amount of the magnetic field-induced martensites is almost constant without regard to the maximum strength of applied magnetic field, if ΔT is kept constant, but it increases with decreasing ΔT. Optical and electron microscopy observations show that the morphology of magnetic field-induced martensites is the same as that of thermally induced ones by cooling below M_s, irrespective of ΔT and H, being lenticular and internally twinned. It is suggested from a consideration based on the results that the raise of transformation temperature is not caused by Zeeman effect alone.

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The present paper is concerned with the kinetics of thermal decomposition of manganese oxides and nonstoichiometric compounds formed in these reaction processes, studied by means of the thermal analyses (TG, DTA and DSC) and gas chromatography (GC).
The decomposition of MnO₂ to Mn₂O₃ proceeds at about 756 K, and the heat of reaction is 176±8 kJ/mol of O₂. For the decomposition of Mn₂O₃ to Mn₃O₄, the activation energy of about 163 kJ/mol of O₂ is obtained. The nonstoichiometric compounds, MnO_1.61 and MnO_1.42, seem to be formed in the thermal decomposition processes of MnO₂ and Mn₂O₃, respectively.

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The extraction equilibrium of aluminum from hydrochloric, nitric and sulfuric acid solutions was studied at 298 K by using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in DOSB diluent.
The ionic strength of all the aqueous solutions was fixed to 3 so that the activity coefficient of species in aqueous phase might be constant during extraction.
The extraction was highly dependent on pH and was expected to be an ion-exchange reaction. Little difference was observed in the extraction equilibria between hydrochloric and nitric acid solutions. In sulfuric acid solution, the distribution ratio of aluminum between the two phases was about one-two hundredth of those obtained in the other acid solutions. The formation mechanism of aluminum complex ion in the aqueous solution was discussed in detail, and it was concluded that the extracted species was the form of AIR₃·2RH monomer in all the acid solutions. The apparent equilibrium constants were 10^−1.16, 10^−1.32 and 10^−1.06 for hydrochloric, nitric and sulfuric acid solutions, respectively.

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Measurements of Young’s modulus at 150–700 K, thermal expansion, hardness and tensile strength at room temperature were carried out for Mn–Cu–Ti and Mn–Cu–Zr alloys subjected to various heat treatments and cold-working. Young’s modulus vs temperature curves of the annealed alloys have a distinct minimum and a maximum, in association with the antiferromagnetic\ ightleftarrowsparamagnetic transition. The Elinvar properties appear in the temperature range in the neighborhood of this anomaly.
The temperature coefficient of Young’s modulus at room temperature is affected by annealing, cold-working, reheating after cold-working and the alloy composition. Young’s modulus and hardness increase with addition of titanium or zirconium. The tensile strength shows a maximum at 3–4% titanium or zirconium. No aging effect on mechanical strength and hardness is observed in the ternary alloys.
Therefore, these alloys are very suitable for use as materials of precision instruments. We call these alloys “MANGALOY”.

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Investigations have been made on the effect of Fe, Co or Ni addition on the thermal expansion, magnetization, lattice constants, hardness and workability of Invar-type Mn-20 and 22%Ge alloys cooled to room temperature at various rates after homogenizing at 1100 K (830°C) for 10.8 ks (3 h). In the thermal expansion vs temperature curves of the ternary alloys containing 10%Fe and Co or Ni less than 5%, a bending point corresponding to the Néel temperature of the ε phase was distinctly observed. Below the Néel temperature, these alloys show very small values of thermal expansion coefficient and the Invar characteristics. The region in which the thermal expansion coefficient at room temperature becomes zero is expanded by the Fe addition, while it is rather reduced by the Ni or Co addition. Temperature dependence of the magnetization of these alloys is very analogous to that of the binary alloys. The ε phase which shows antiferromagnetism at room temperature is stabilized by the addition of Fe, Co or Ni.
The Vickers hardness of the Mn-20%Ge alloy is decreased at first from 500 to about 400 by the addition of a few per cent of Fe, and then a value of about 400 persists up to 10%Fe. The performance of cutting and forging of the binary alloys has much more been facilitated by the addition of Fe, Co or Ni.

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The twin-roll rapid solidification process was investigated both experimentally and theoretically to explore rolling characteristics of the process.
Results of the experiment using a Pb–Sb eutectic alloy show that the thickness of a rapidly solidified metallic ribbon decreases with increasing roll rotation speed and with decreasing initial roll gap and melt flow rate. The cross-sectional area of the ribbon is in proportion to the ratio of the melt flow rate to the roll rotation speed and does not depend on the initial roll gap.
Based on the reduction ratio in thickness of the solidified ribbon and the roll gap enlarged by a rolling load, effects of key process parameters on the ribbon geometry are discussed. The calculated roll separating force has been confirmed to agree well with the observed value.

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