The equilibrium phase diagram in a pseudo-binary Al_80−xPd₂₀Mn_x (x=3 to 15 at%) system was examined with the aim of searching an alloy composition at which the icosahedral (I) phase precipitates directly from liquid as a primary phase. The I-phase precipitated as the primary phase in the range of 3 to 9%Mn and as the second phase through the peritectic reaction in the range of 9 to 15%Mn. From further detailed examinations of Pd and Mn contents, an optimum composition to obtain the primary I-phase is concluded to be Al_71.5Pd_20.3Mn_8.2. Subsequently, the preparation of the I-ingot with a large single domain size was tried at the optimum composition in various melting conditions. As a result, the inoculation and drawing-up treatment with a polycrystalline BN needle in an arc melting with a hemishere copper mold was found to be effective in controlling the nucleation and growth of the I-phase and the largest domain size reached as large as 8 mm. The formation of the large single domain was also confirmed from the evidence that the X-ray Laue patterns taken from the inoculated ingot reveal the five-, three- and two-fold symmetries.

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Irradiation experiment was carried out in the bulk of amorphous (Pd₈₀Si₂₀)_96.5Li_3.5 by light ions, which are produced by the following nuclear reaction in a nuclear reactor:
⁶Li+n→³H+⁴He
Structural changes before and after irradiation were determined by X-ray diffraction, small angle X-ray scattering and EXAFS (extended X-ray absorption fine structure) measurements. Scattering amplitudes in the X-ray diffraction and EXAFS decreased after irradiation with much less radiation fluence than by that previously done by the Van de Graaff accelerator. The scattering intensity in small angle region increases with the increase in radiation fluence.

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Multilayered films consisting of Ag and Cu layers were prepared by evaporation and sputtering methods, and studied by mainly X-ray diffraction. X-ray diffraction profiles showed that artificial layer periods were realized by both methods. In the analysis of multilayered films, we adopted an ideal model that a compositional modulation is expressed in terms of a periodic rectangular concentration of the constituent element, and compared thus calculated profiles with the observed ones. It is shown that the interplanar spacing of each element is not the same as that of each bulk material, especially for small layer periods, and that the deviation of interplanar spacing appears slightly larger for dc-sputtering than for evaporation. The present evaluation procedure is found to be informative for characterization of structural features of multilayered films. We also discuss the structural change due to substrate temperature for several films prepared by the evaporation method.

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Hydrogen diffusivity and solubility in pure solid aluminum were measured in a high temperature range from 573 to 923 K, by means of a desorption technique, which was an outgassing study from thermally hydrogen-charged cylindrical samples with various grain sizes. The diffusion coefficient depended linearly upon an inverse of temperature in the Arrhenius plot. There were two characteristics in the plot; one of them was a change of apparent activation energy for diffusion being a fixed diffusivity at about 900 K, while another was a correlation between the increase of activation energy and the decrease of grain size. We proposed a simple model for grain size dependence of the hydrogen diffusivity. The decrease in diffusivity at a lower temperature for the smaller grain size was explained by trapping of hydrogen at nodes of grain boundaries. In a very large grain size, there was a possibility of a fast diffusion along the grain boundary. The increase in solubility usually expected from a trapping process was not found in this study.

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It was shown in the previous studies that measured hydrostatic pressure dependence of M_s temperature in Fe–Ni and Fe–Ni–C invar alloys was not in agreement with the one calculated by using a modified Patel-Cohen’s equation, although it was in good agreement in an Fe–Ni–C non-invar alloy. It was then speculated that the disagreement for invar alloys might be caused by the existence of spontaneous volume magnetostriction, which was one of physical properties related to the invar nature. In order to quantitatively confirm the speculation, the spontaneous volume magnetostriction of an Fe-29.9 at%Ni invar alloy has been obtained by measuring the spontaneous magnetization under hydrostatic pressures. Then, a new equation including a term due to the spontaneous volume magnetostriction to estimate the pressure dependence of M_s temperature has been derived by referring to the Patel-Cohen’s equation. The pressure dependence of M_s temperature for the Fe–Ni invar alloy has been then calculated by putting the obtained spontaneous volume magnetostriction and other physical quantities, such as bulk modulus, into the newly derived equation. As a result, the calculated pressure dependence was in almost good agreement with the previously measured one in the pressure range examined. It was thus concluded that the previous speculation and the newly derived equation were quantitatively confirmed.

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The composition dependence of the atom locations of the third elements in Ti–Ni–X shape memory alloys (X=Cr, Mn, Fe, Co or Cu) has been investigated by the electron channelling enhanced microanalysis. As a result, the followings were clarified: All the added third elements mainly occupied the Ni atom site for the Ti₅₀Ni_50−xX_x alloys. However, different atom sites were occupied depending on the kind of the third elements for the Ti_50−xNi₅₀X_x alloys, that is, Mn and Cu mainly occupied the Ti atom site while Fe and Co did the Ni atom site, and Cr occupied both the atom sites with nearly the same probability. A thermodynamic consideration has been done on the above results, that is, the free energy of the alloy systems was calculated on the basis of the Bragg-Williams approximation, taking account of the configurational entropy, and the atom location of the third elements was determined so as to minimize the free energy. The atom location thus obtained was qualitatively in good agreement with the experimentally determined one. A slight disagreement was found between the calculation and experiment, and it appeared to be due to the size difference among the third element and the host atoms.

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In an attempt to clarify the structure of the ⟨110⟩ fiber texture in the central area of a hot-rolled silicon steel sheet, computer color mapping was performed with an image analyzer by using the orientation and strain data measured by a Kossel examination. The results are summarized as follows:
(1) The central area of the hot-rolled silicon steel sheet was composed of grains elongated in the rolling direction, and had ⟨110⟩ fiber textures of {100}⟨011⟩, {100}⟨001⟩, near {113}⟨110⟩, and near {223}⟨142⟩ orientations. In this area, no {110}⟨001⟩ grains were formed.
(2) In all the elongated grains, strain existed inside the grains. Among them, the elongated {100}⟨011⟩ and {100}⟨001⟩ grains had a small amount of strain and a low lattice curvature (within 10°) in the same grain, whereas those of near {113}⟨110⟩ and near {223}⟨142⟩ grains had a large amount of strain and a high lattice curvature (max. 30°).
(3) This result is consistent with many previous experimental results for cold rolling and recrystallization with single crystals of silicon steel.
(4) Most of the elongated grains had high-angle grain boundaries displayed with a boundary width of 3 pixels, where the deviation angles of mutual grains were more than 25°.
(5) An alternate formation of {100}⟨011⟩ or {100}⟨001⟩ and near {112}∼{111}⟨110⟩ elongated grains occurred during the processes from slab heating to hot rolling. Thus, the energy decrease due to this alternate formation of elongated grains with these orientations played a more important role in the development of (110) [001] secondary grains than the energy increase due to the formation of high-angle grain boundaries. This alternate formation is indispensable for developing (110) [100] secondary grains in the processes up to secondary recystallization after hot rolling.

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The influence of solution-annealing conditions (temperature and time) on the nucleation and growth of grain boundary cells in the 0.2%Si-doped Cu-10%Ni-8%Sn alloy on aging at 723 K was investigated by the quantitative metallographic method. The hardness change in the matrix during aging at 723 K was scarcely affected by the solution-annealing conditions. However, the nucleation and growth of the cell during aging was remarkably affected by the solution-annealing conditions. When the solution-annealing temperature or time was increased, the suppressing effect of Si on the cellular precipitation was decreased. The Ni₃₁Si₁₂ phase particles which existed in the matrix grains and grain boundaries in the as-quenched specimen were coarsened with increasing solution-annealing temperature or time. Therefore, it is suggested that in the specimen solution-annealed at a higer temperature or for a longer time, the effects that the Ni₃₁Si₁₂ phase particles occupy the nucleation sites of the cells in the grain boundaries and suppress the migration of the advancing boundaries of the cells on aging were decreased.

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An analytical description of the normalized creep function for the case of a lognormal distribution of relaxation times is presented. Some properties, as inflection points, recurrence relations, etc., are given, which can be used for a direct comparison with the experimental data.
Finally, it is shown how the formalism presented can be used to obtain, with great accuracy, the parameter of the distribution and the most probable value of the relaxation time from the experimental data.

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The superplastic deformation of mechanically alloyed aluminum has been shown to occur at unusually high strain rates. Although superplastic elongations of up to 570% have been obtained, the strain rate sensitivity, m, is low, between 0.25 and 0.3. An analysis of the threshold stresses present due to the dispersed particles indicates that the rate limiting deformation mechanism is not grain boundary sliding (which was observed), but solute atom drag of dislocations in the bulk of the grains. Deformation in the superplastic regime occurs without cavitation, due to rapid diffusion and easy intragranular slip to accommodate stress concentrations in the boundary. Two phenomena that reduce potential elongation are serrations in the flow curve (from solute atom breakaway), and the effects of thermal flow instabilities arising from conduction of adiabatically generated heat into specimen ends. The effect of alloying composition on deformation mechanisms is described. Modifications to the alloy composition and the mechanical alloying process that may improve the superplastic forming potential of mechanically alloyed aluminum are suggested.

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A new electrical equivalent circuit accounting for metal/solution interface about the surface heterogeneity of electrodes was proposed instead of the known semi-circular law. The present equivalent model consists of a ladder network of elements, where each element is made of a solution resistance in series with a parallel combination of double layer of capacitance and charge transfer resistance. The parameter σ, the standard deviation of normal distribution of double layer capacitance affected the depressed semi-circular arcs of different extent, which may be caused by various heterogeneities of the surface reactivity. The circuit which gives a depressed semi-circular arc is in agreement with the results of electrodeposition of copper from acidic copper sulphate solution.

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The method for the determination of oxygen in iron containing aluminum was studied by use of the inert gas fusion-infrared absorptiometry as a function of flux, temperature and heating pattern. The double graphite crucibles containing Sn in excess of four times as much as the sample weight were first degassed at 3000 K, and the temperature was lowered to 2630∼2760 K. Then the sample enclosed by nickel capsule was dropped into the tin bath and fused for 30 s. This analytical procedure made the oxygen determination in an Fe-10∼15 mass%Al alloy possible without observation of “gettering effect” due to aluminum. The value for oxygen recovery was confirmed to be almost 100% by the analysis of alumina powder. The results for the oxygen in a Ti-25∼51 mass%Al alloy was also discussed.

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The nitriding behavior of chromium as a function of temperature and the corrosion resistance of the nitriding products in a sulfuric acid solution were investigated. Nitriding of chromium starts at about 873 K, and the surface product is a mixture of α-Cr and hexagonal Cr₂N. The product changes to a mixture of Cr₂N and cubic CrN at 973∼1273 K, and it transforms into the single phase Cr₂N by the dissociation of CrN above 1323 K. Chromium loses the ability of self-passivation with nitriding, but the surface product at 973∼1273 K exhibits a low current density in the anodic polarization measurement, which is comparable with the passive current density of chromium. The mixture of Cr₂N and CrN containing 33 at% nitrogen or more shows improved corrosion resistance in 1 kmol·m⁻³ H₂SO₄ at 373 K, although the mixture of α-Cr and Cr₂N, and the single phase Cr₂N are rapidly attacked. This means that the single phase CrN should have a high corrosion resistance. Cyclic voltammetry reveals that chromium nitrides dissolve mostly as Cr²⁺ ions. The Cr²⁺ ions are presumed to be oxidized to Cr³⁺ ions on platinum surface by the catalytic action.

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Soft magnetic ferrites in now use as magnetic devices have a disadvantage that the saturation magnetization is considerably lower than that of metallic soft magnetic materials. The low saturation magnetization prevents us to give a higher degree of performance for transformers and inductors and to cause an increase in the density of magnetic recordings.
The present authers found out the Mn–Zn ferrites containing Er₂O₃ with improved saturation magnetization and relative permeability.
When Er₂O₃ is added at the composition range of 0.005∼0.5 mol% to Mn_0.54Zn_0.36Fe_2.10O₄ single crystal, saturation magnetization (σ_s) and relative permeability (μ_r′) are increased by the addition of Er₂O₃, showed maximum values of 10.56×10⁻³ Wbkg⁻¹ and 640 at 5 MHz, respectively, at about 0.05 mol%Er₂O₃ and then decrease significantly with further increasing Er₂O₃ content.
At the composition range of 51∼56 mol%Fe₂O₃, 24∼34 mol%MnO and 13∼21 mol%ZnO, the σ_s for the single crystals in Fe₂O₃–MnO–ZnO and Fe₂O₃–MnO–ZnO-0.05 mol%Er₂O₃ systems tends to increase with increasing Fe₂O₃ and MnO contents, but σ_s value of the ferrite containing Er₂O₃ increases with further increasing MnO content than that of Fe₂O₃–MnO–ZnO system. The compositional dependences of μ_r′ value for single crystals in both Fe₂O₃–MnO–ZnO and Fe₂O₃–MnO–ZnO-0.05 mol%Er₂O₃ systems are nearly the same. However, the Er₂O₃-containing ferrites exhibit the μ_r′ values higher than that of the ferrites without Er₂O₃ in the entire composition range. The effect of the Er₂O₃ addition on magnetic properties is closely related to the dissolve of Er³⁺ ions in the Mn–Zn ferrite.

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Present works describe the improvement of the magnetic properties of Sm(Fe, Ti)₁₂ melt-spun ribbons with ThMn₁₂-type structure. In order to increase the remanence, the Ti content was decreased and the heat treatment temperature and time were lowered and shortened, respectively. As a result, the maximum energy products increases. The (BH)_max of 56.8 kJm⁻³ (7.1 MGOe) was obtained with SmFe_11.25Ti_0.75 melt-spun ribbons annealed at 770°C for 10 min. This is the highest energy products among reported values on melt-spun ribbons in ternary Sm–Fe–Ti system so far. The Co addition is effective for increasing the saturation magnetization. Sm(Fe_0.8Co_0.2)_11.25Ti_0.75 melt-spun ribbon exhibits the high maximum energy products of 67.2 kJm⁻³ (8.4 MGOe) after annealing at 800°C for 10 min. Microstructural studies indicate that the ribbons consist of fine grains which have the average grain diameter of nearly 40 nm.

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