Age-hardening of some high purity Cu–Be binary alloys has been studied and the hardening curves were classified into three distinct types: Type-1, Type-2 and Type-3. As the low temperature ageing process can be clearly distinguished from the high temperature ageing process in such binary alloys, two C curves are obtained corresponding to the respective processes.
Complete reversion of hardness was found to occur, if the hardening process prior to the reversion treatment remains within the zone formation stage. The reversion temperature corresponds to the lower temperature limit, above which the Type-3 ageing, i.e. purely high temperature ageing, will occur, as shown in Al–Cu alloys by Beton and Rollason. This occurrence of reversion was confirmed by means of transmission electron microscopy and a selected-area diffraction technique.
The reversion temperature of the G. P. zone determined from this experiment is found to be raised with increase in solute concentration than that in the case of Al–Cu alloys (430°∼450°C for 1.91 wt% Be and, 330°∼380°C for 1.64 wt%Be alloy).
Reageing after reversion was also investigated which occurs at a much slower rate within the zone formation stage (Type-1 and the early stage of Type-2) because of the remarkable decrease in the number of quenched-in vacancies, but the reduction in rate was found to be much less in the stage of high temperature ageing (Stage-2).
The effect of Fe, Al, Si and Co has also been studied. Among these, Co was found to be most effective in retarding the zone formation. This seems to be the cause of the difference between the ageing behaviours of those binary alloys and commercial beryllium copper.

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From a structural consideration of the silicate melt, the free energy of solution and the components’ activities of melts of the M_IO–M_IIO–SiO₂ type were evaluated. When a parameter is known as to each binary M_IO–SiO₂ or M_IIO–SiO₂ system (which has been discussed in the previous paper), the extension to the ternary system was found to be carried out without difficulty. A new scale of basicity of the silicate melt of this type was proposed.

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The recrystallization process in a 50%Ni–50%Fe alloy sheet 96% cold rolled was studied by a transmission electron microscope.
In the early stage of recrystallization, a cube grain grew mainly at the band-like structure consisting of (110) [1\bar12] and weak (100) [001] components of cold rolled texture. A high dislocation density region was found in a slightly grown cube grain when annealed at 490°∼520°C for 30 min. Such a region was found only one in each cube grain, and its size was compared to the subgrain size of the band-like structure.
It was presumed that the cube grain grew from the region by subgrain boundary migration, without inverse Rowland transformation.

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The early stage of ageing in lead-0.4 wt% magnesium alloy was examined by means of resistivity measurements. It was found that resistivity increases during isothermal ageing at temperatures below 50°C, after quenching from 250°C into iced water at 0°C. The increase in resistivity is attributed to clustering of solute atoms. On the other hand, a decrease in resistivity is observed during ageing at temperatures above 60°C. At the ageing temperatures 30°∼50°C, the clustering takes place in a single stage of the first order rate process with an activation energy of 0.44 eV . At the ageing temperatures below 30°C, the clustering takes place in two stages. The first and second stages are zero and first order rate processes, respectively. The activation energy for zero order rate process is 0.53 eV.
The kinetics of clustering is interpreted on a hypothesis that the quenched-in vacancies act as catalyst for the clustering reaction. According to the hypothesis, the activation energies for the reactions of zero and first order are assigned to (E_M+B) and E_M, respectively, where E_M is the activation energy for migration of a vacancy and B the binding energy between a solute atom and a vacancy. It is deduced that E_M is 0.44 eV and B is about 0.1 eV in this alloy.

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In recent years, with the increasing emphasis on reliability of metal-to-ceramic seals, greater attention is being paid to Mo–Mn–Ti metallizing and Cu brazing. In response to these recent trends, the bonding mechanisms of Mo–Mn–Ti metallizing and Cu brazing were studied by means of the seal strength test, the heat cycle test, optical and electron microscopic observations, and electron probe microanalysis. The results obtained are as follows: The bonding of the Mo–Mn–Ti metallizing can be considered to consist of three different mechanisms; the primary bonding due to the formation of the reaction product layer, the secondary bonding due to the migration of the glassy phase, and the tertiary bonding due to the sintering of the metallized layer itself with a reactive liquid. The complete bonding is accomplished by the tertiary bonding. Various theories proposed hitherto are thought to be an interpretation only for the primary or secondary bonding. Also, the Cu brazing contains a phenomenon associated inevitably with its high temperature processing. This is the reason for the rapid decrease in both seal strength and vacuum tightness in the Cu brazed metal-to-ceramic seals by the heat cycling.

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The impurity cell structure of rapidly cast Al–Si, Al–Mg and Al–Ag alloys is investigated with respect to the occurrence of second phase and dislocations as a function of solute concentration. Considering the dislocation arrangement, three types of cell boundaries corresponding to various concentration ranges could be distinguished. Comparison of the three alloys leads to the conclusion that the dislocations are introduced by constitutional stresses, which depend only on the severity of segregation and the difference in atomic size between solvent and solute atoms.

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Kobayashi and two of the present authors discovered in a previous work that nickel-manganese alloys exhibit high permeability in the concentration of less than about 24% manganese, and named them Nimalloy. Much subsequent work has been carried out on the effects of additions of various elements on the properties of nickel-manganese alloys and obtained the highest initial permeability of 76000 and the highest maximum permeability of 441000. In the present paper, the effect of aluminium additions on the characteristic properties of nickel-manganese alloys have been studied. The results show that the optimum cooling rate for attainment of the highest permeability in each alloy increases in general with increasing aluminium content. Thus the alloy containing 78.95% Ni, 19.85% Mn and 1.20% Al showed the highest initial permeability of 10780 when cooled at a rate of 400°C/hr from 900°C and the alloy containing 78.81% Ni, 19.56% Mn and 1.63% Al exhibited the highest maximum permeability of 73200 when cooled at a rate of 800°C/hr from the same temperature; the latter shows a magnetic hysteresis loss of 9.49 erg/cm³/cycle and a coercive force of 0.0121 Oe for the maximum magnetic induction of 2000 G, and a specific electrical resistivity of 61.0 μΩ-cm at 20°C.

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Cylindrical single crystals of nickel were prepared and their thermal expansion and Young’s modulus were measured over the temperature range of 0°∼500°C by a dilatometer and by means of an electrostatic type vibrator-controlled oscillator system, respectively. Then, from the measured values, the elastic parameters S_ij, Young’s modulus for three principal directions of single crystals and for a polycrystal of nickel were calculated. It has been known that there is a similar temperature dependence of Young’s moduli in the three principal directions and of Young’s modulus of a nickel polycrystal, and the calculated values of Young’s modulus for a polycrystal agree well with the measured values of the annealed polycrystal specimen. The calculated Young’s moduli at 20°C are 1.21×10¹², 2.04×10¹², 2.62×10¹² and 1.90×10¹² dyn/cm² for the directions of ⟨100⟩, ⟨110⟩, ⟨111⟩ of the single crystals and for a polycrystal, respectively. The crystal anisotropy E_⟨111⟩⁄E_⟨100⟩ of the nickel single crystals at 20° and 150°C are 2.17 and 2.49, respectively.

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The strain gauge factor K at room temperature, the electrical resistivitity ρ at 20°C and its mean temperature coefficient C_f, and the mean thermo-electromotive force E_mf in the temperature range 0° to 40°C have been measured with wires of Fe–Cr alloys containing 0∼50% chromium in a cold-worked state of about 98% reduction. It has been found that the largest value of K obtained is 6.2 for the iron-chromium alloy containing 20% chromium, ρ, C_f and E_mf of which are 44.6 μΩ-cm, 32.7×10⁻⁴ and +11.0 μV/°C relative to copper, respectively.

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The present investigators already measured the strain gauge factor K and electrical properties for the wires of Fe–Cr alloys containing less than 50% chromium, and obtained the largest value of 6.2 in K for the alloy containing 20% chromium. So they have further investigated the influence of the addition of less than 70% cobalt or 65% nickel on their properties. Although K of Fe–Cr alloys shows some decrease with increasing cobalt or nickel content, the electrical resistivity ρ increases considerably, while the mean temperature coefficient of electrical resistivity C_f and the mean thermo-electromotive force relative to copper E_mf decrease and reach comparatively small values. The results on Fe-15%Cr-35%Co and Fe-10%Cr-20%Ni alloys show that K is 3.9 and 3.7, ρ is 88.6 and 86.0 μΩ-cm, C_f is 2.6×10⁻⁴ and 3.0×10⁻⁴, and E_mf is −0.1 and −4.7 μV/°C, respectively.

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By thermal analysis and electrical resistivity measurement, the formation of a metastable state (Borelius’s ε′ and ε states) during quenching Al-rich Al–Ag alloys has been observed, separately from the cold hardening stage (η state) and the warm hardening stage (precipitation of γ′ and γ phases from the matrix δ phase). Based on the specific heat versus temperature curves obtained during the heating of specimens of various Ag concentrations immediately after quenching, the temperature limit of existence of the ε state has been determined and is shown in the phase diagram, but it does not correspond with the solubility curve of metastable fcc Ag clustering determined based on the thermodynamic data by Hillert, Averbach and Cohen. The heat absorbed during the transitional change from the ε state to the homogeneous δ state is 12 cal/mol for 0.25 atomic percent Ag alloy and increases linearly with Ag concentration to 190 cal/mol for 5.9 atomic percent alloy. It has been confirmed that the ε state is not directly responsible for the cold hardening and its reversion.

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The reaction between silica and carbon was investigated in argon and carbon monoxide atmospheres as a fundamental research of the direct reduction of aluminium, because silica is involved in the source materials. When the pellet consisting of SiO₂/C=1/2 was heated in argon, SiO₂ gas was evolved above 1300°C and only silicon carbide was formed by the following reactions:
SiO₂(s)+2C(s)=SiO(g)+CO(g) and SiO(g)+2C(s)=SiC(s)+CO(g).
The above reaction occurred at higher temperatures in CO atmosphere.
Metallic silicon was found by the reaction between silicon carbide and SiO gas evolved from the SiO₂–C mixture at 1900°C, and this reaction was assumed to be SiC(s)+SiO(g)=2Si(l)+CO(g).
When the pellet consisting of a SiO₂–SiC mixture was heated, metallic silicon was also formed owing to the reaction of SiO₂(l)+2SiC(s)=3Si(l)+2CO(g). Therefore the above two processes were estimated to be the main mechanisms for the production of silicon.
The fractions of SiC, Si, SiO and SiO₂ formed in the cases of SiO₂–C and SiO₂–SiC mixtures were determined up to 2000°C, and their reaction processes were considered thermodynamically.

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