High resolution transmission electron microscopy (HRTEM) has been applied to verify the validity of the O-lattice theory for geometrical approach to the grain boundary structure, then periodic structures predicted from the O-lattice theory have been compared with the HRTEM images. In addition, the correlation between the grain boundary energy and the grain boundary structure has been discussed. Main results obtained are as follows.
(1) The predicted periodic structure of an arbitrary ⟨110⟩ symmetric tilt grain boundary is consistent well with the observed one irrespective of the nature of the atomic bonding.
(2) There is a good correlation between the misorientation-dependence on grain boundary dislocation density and that on grain boundary energy, suggesting that main part of the grain boundary energy comes from elastic and core energies of grain boundary dislocations.
(3) The energy per grain boundary dislocation is less dependent of the magnitude of the Burgers vector but depends on the parameter defined as the grain boundary dislocation density normalized by their Burgers vector, b⁄D, within the range of 0.1\lesssimb⁄D\lesssim1.

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Ribbons with the composition Al–12.5Si–1Mg were prepared by melt spinning. X-ray diffraction of as melt spun ribbons showed complete solubility of Si in aluminum. The as melt spun resistivity was 36 μΩ cm for ribbons of 24 μm thickness. This value relaxes to 9.0 μΩ cm on prolonged annealing. The hardness of the as melt spun ribbons was 1500 MN/m², and relaxes to reach a value of 800 MN/m² after prolonged annealing. The activation energy estimated from isothermal ageing ranged from 1.05 to 1.26 eV. An equation is given to fit the kinetics of relaxation. Discussion of resistivity and hardness relaxation is given and is related to ordering and silicon precipitation.

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The metastable microstructures in two rapidly solidified Ni rich Ti–Ni alloys are studied. A first report of the presence of a cubic phase with three times the lattice parameter of B2-TiNi in melt spun Ti₄₀Ni₆₀ alloy is presented. This phase has precipitated from the massively solidified B2-TiNi. We also report the formation of a faulted structure (A⁹), polytypic to TiNi₃ along with TiNi₃ in melt spun Ti₃₀Ni₇₀ alloy. It is argued that this structure is stabilised due to a specific valence electron by atom ratio.

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The precipitation and dissolution behaviors of various alloying elements by accumulative isochronal treatment were investigated in the high-purity Al-0.35 mass%Zr alloys containing 0 to 0.2 mass%Fe or 0 to 0.2 mass%Si and the commercial Al-0.35 mass%Zr alloys containing 0.15 mass%Fe and 0.05 to 0.15 mass%Si. The solute concentrations of the alloying elements are discussed in terms of the changes in resistivity and in amount of the precipitated elemental Si determined by wet chemical analysis (WCA). In the accumulative isochronal heat treatment, i.e. holding for 3.6 ks at temperatures of every 50 K, the addition of Fe slightly accelerates the precipitation of Zr, while the addition of Si significantly accelerates the precipitation of Zr. The most significant acceleration of Zr precipitation is observed at temperatures 50 to 100 K lower than the temperature at which the maximum amount of Zr precipitates both in the Al–Zr–Fe and Al–Zr–Si alloys. The effects of Fe and Si additions on the precipitation of Zr are considered to be mainly attributed to solute Fe and Si atoms, respectively. The stagnation of decrease in resistivity is observed at 523 to 623 K in the high-purity Al–Zr–Si alloys. In the commercial Al–Zr–Fe–Si alloys, the resistivity either stagnates or even re-increases at 523 to 573 K. The change in the amount of precipitated elemental Si in the commercial alloys, estimated by the WCA, corresponds well with the stagnation or the re-increase of resistivity.

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To investigate the characteristics and effects of dynamic strain aging (DSA) and dynamic precipitation of austenitic Fe–Mn–Al–C alloys, a hot-rolled alloy (Fe–26Mn–9Al–0.9C, in mass%) and two cast alloys (Fe–35Mn–9Al–1C, Fe–32Mn–9Al–1C) were selected to perform tensile test at various temperatures from 298 to 1073 K. The strain rates were chosen in the range from 9.4×10⁻⁵ to 9.4×10⁻³ s⁻¹.
As indicated from the appearance of serrated flow, DSA occurs in two temperature regimes. Judging from the apparent activation energy obtained at the onset temperatures of serration, carbon atmosphere drag plays a role in the serration and the temperature independent flow stress in the low temperature regime. In the high temperature regime, the serration cannot be solely accounted for by the diffusion of manganese or aluminum solute atoms, or both. During high temperature deformation, the precipitation of Fe₃AlC_x occurs on active slip planes and along grain boundaries, giving rise to a substantial strengthening effect as compared with that normally associated with DSA. Grain boundary precipitation also leads to grain boundary embrittlement at the temperatures higher than about 773 K. All the above features and effects are common in the three test alloys although the hot-rolled alloy contains about 4 vol% ferrite.

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Phase equilibrium studies of the ternary system Bi–Ca–O at 1000 K and ambient pressure indicate that all the ternary oxides lie along the pseudo-binary line Bi₂O₃–CaO. Four ternary oxides, Bi₂Ca₂O₅, Bi₆Ca₄O₁₃, Bi₂CaO₄ and Bi₁₄Ca₅O₂₆ and two phases of variable composition (δ and β) are identified. The chemical potential of CaO in two-phase fields of the pseudo-binary Bi₂O₃–CaO is determined as a function of temperature using solid state cells based on single crystal CaF₂ as the electrolyte. The chemical potential of Bi₂O₃ in the two-phase fields is measured using cells incorporating (Y₂O₃)ZrO₂ as the solid electrolyte. The standard Gibbs free energy of formation of each ternary oxide from the binary oxides is calculated independently from the chemical potentials of CaO and Bi₂O₃ in two-phase fields on either side of the compound composition. The independent assessments agree closely; the maximum difference in the value of ΔG_f⁰(Bi_2mCa_nO_3m+n)/(m+n) is 170 J/mol of the component binary oxides. The results are discussed in the light of the phase diagram and compared with calorimetric and free energy measurements reported in the literature. The combined use of emf data from cells incorporating fluoride and oxide electrolytes enhances the reliability of derived data. Free energies of formation of ternary oxides from component binary oxides are given by the following equations:
Bi₂Ca₂O₅: ΔG⁰_f,ox(J/mol)=−43800+5.79T(±900)
Bi₆Ca₄O₁₃: ΔG⁰_f,ox(J/mol)=−109800+7.04T(±2300)
Bi₂CaO₄: ΔG⁰_f,ox(J/mol)=−31910+2.31T(±650)
Bi₁₄Ca₅O₂₆: ΔG⁰_f,ox(J/mol)=−184560+12.76T(±4320)
Bi_1.4Ca_0.3O_2.4 (β): ΔG⁰_f,ox(J/mol)=−12290(±300) at 900 K
Bi_1.56Ca_0.22O_2.56 (β): ΔG⁰_f,ox(J/mol)=−9890(±180) at 900 K

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It was found that tetragonal PbO has an ionic conductivity, and the solid state cell using the oxide as an electrolyte has become of interest in recent years. In this study, the PbO₂/Pb interfaces, which were obtained by both pressing and electrolyzing, were heated to produce an electrochemical cell at 333 K. The electromotive force and the impedance response of the cell were measured during the heat-treatment. As there is a complete continuity of composition at the interface obtained by electrolyzing, a resistant oxide layer readily grows by heating. The electromotive force of the cell by electrolyzing rises to about 45% of the theoretical value, while that of the cell by pressing is on a μV level. An X-ray analysis confirms that the electromotive force of the cell is caused by the resistant oxide, tetragonal PbO formed in the PbO₂/Pb interface. The electromotive force of the cell by electrolysing decreases rapidly during the initial stage of a constant resistance discharge at room temperature, but the degradation is restrained by a rise in working temperature.

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The pitting corrosion behavior of the melt-spun amorphous Ni–Zr alloys with 30–75 at% zirconium, the crystalline arc-melted counterparts and the sputter-deposited Ni–Zr alloys with 20–84 at% zirconium was examined by electrochemical measurements in deaerated 0.5 kmol/m³ H₂SO₄ with and without 0.1 kmol/m³ NaCl at 303 K. In the sulfuric acid solution without Cl⁻, these alloys were spontaneously passive and their potentiodynamic behavior was similar to each other. In the Cl⁻-containing solution, all the melt-spun amorphous alloys suffered pitting during anodic polarization and the pitting potential decreased with an increase in zirconium content. On the other hand, the crystalline arc-melted low zirconium alloys suffered pitting but no pitting observed for the crystalline alloys containing 70 at% zirconium or more. In addition, the pitting potential increased with the zirconium content of crystalline alloys. All the sputter-deposited alloys did not suffer pitting regardless of the amorphous and crystalline structures. Therefore, the melt-spun amorphous alloys were the most susceptible to pitting corrosion. A marked difference was observed in the pitting behavior between the shiny side (top side) and the dull side (wheel side) surfaces of the melt-spun ribbon. The pits initiated from the dull side surface. Thus, the dull side surface could be responsible for such an unusual pitting behavior of the melt spun ribbon.

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A new method by applying high-purity ozone exposure and ultraviolet (UV) irradiation has been used for cleaning the surface of ultra high-purity iron with a carbon contaminated layer. The amount and chemical state of elements on the specimen surface were characterized by X-ray photoelectron spectroscopy. The intensity of the C 1s XPS peak due to carbon contamination was found to decrease with increasing ozone exposure at room temperature. UV irradiation during ozone exposure enhanced the cleaning rate. The XPS results show that contaminated carbon is mainly classified into major aliphatic carbon and minor carboxyl carbon, and their ratio depends upon the condition of ozone exposure. The role of ozone exposure and UV irradiation was discussed with respect to surface cleaning.

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A Zn–Al–Cu–Mg alloy for use as a molding tool material has been developed. Acceptable mechanical properties can be obtained in a composition range where the Cu-rich ε phase appears as one of the eutectic components.
An inverse sand mold casting technique that has been developed from trials using small size cylindrical molds is demonstrated to be beneficial for the suppression of microporosity formation, grain growth, and gravity segregation of Al. The mechanical properties of heavy sectioned castings of the alloy are also increased by the casting technique.

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A Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy subjected to B₂O₃ flux treatment was found to have a low critical cooling rate (R_c) of 0.100 K/s for glass formation and a large sample thickness (t_max) of 72 mm by the water quenching process. The R_c and t_max exceed largely those (R_c=1.57 K/s, t_max=40 mm) for the Pd–Cu–Ni–P alloy without the flux treatment. It is concluded that the flux treatment causes a significant increase in the thermal stability of the supercooled liquid. The glass transition temperature (T_g) remains unchanged in the fluxed state, but the crystallization temperature (T_x) increases by 7 K, leading to the extension of the supercooled liquid region defined by ΔT_x(=T_x−T_g) to 98 K which is larger than that (91 K) for the non-fluxed sample. The decrease in R_c and the increases in t_max and ΔT_x for the fluxed sample are presumably due to the suppression of heterogeneous nucleation for crystallization resulting from the increase in the degree of cleanness of the molten alloy. Besides, the Pd–Cu–Ni–P amorphous alloy has lower R_c and melting temperature (T_m) and larger t_max, ΔT_x and T_g⁄T_m values, as compared with those for Pd₄₀Ni₄₀P₂₀ alloy. The larger glass-forming ability for the Pd–Cu–Ni–P alloy is presumably due to the increase in the degree of the satisfaction of the three empirical rules for the achievement of larger glass-forming ability resulting from the more systematic change in atomic size in the order Pd>>Cu>Ni>>P and the generation of Cu–Pd and Cu–P atomic pairs with negative heats of mixing. There is no appreciable difference in the T_g, T_x and crystallization behavior between the cast 72 mm^φ amorphous ingot and melt-spun amorphous ribbon. The finding of the fluxed Pd₄₀Cu₃₀Ni₁₀P₂₀ alloy with the lower R_c and larger t_max values is promising for the future development of bulk amorphous alloys.

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High vacuum, containerless, electrostatic levitation process has been used to study the undercooling and crystallization kinetics of a bulk glass forming Zr–Ti–Cu–Ni–Al alloy. The oxygen impurity level in the alloy has been found to play a crucial role in the crystallization kinetics of the undercooled melt. Overheating the melt above a critical threshold temperature results in enhancement subsequent undercooling. This crucial threshold temperature is found to be a function of the overall oxygen content of the alloy direct measurement of the time-temperature-transformation (TTT) diagram for crystallization of the undercooled melt made following initial overheating above the threshold temperature show a strong dependence on overall oxygen concentration. An explanation of these observations is proposed.

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The role of small additions of Ag in increasing the nucleation frequency of a plate shaped precipitate having {111}_Al habit plane, designated Ω, in an Al–Cu–Mg alloy has been investigated using transmission electron microscopy (TEM), electron diffraction and energy dispersive X-ray spectroscopy. The results provide for the first time direct evidence showing association of Ω plates with small Ag-rich precipitates of the constituent binary Al–Ag system during the early stages of artificial aging. Given the strong attraction between Ag and Mg owing to the large difference in electronegativity between them, Mg simultaneously combines with the Ag-rich precipitates formed on the {111}_Al matrix planes, and makes such sites suitable for the heterogeneous nucleation of Ω phase.

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