The atomic structures of Zr₇₀Ga₁₀Ni₂₀ amorphous alloys exhibiting a wide supercooled liquid region have been studied by the anomalous X-ray scattering (AXS) method. The local atomic structures around Zr, Ga and Ni have been determined in the amorphous samples as-quenched and annealed in the supercooled liquid region so that the atomic structure in the supercooled liquid region was compared with the one in the as-quenched state. The structural analyses and differential scanning calorimetry (DSC) traces in the as-quenched and annealed samples indicate that a structural change in the environment for Zr due to annealing in the supercooled liquid region is closely related with the thermal stability in the present amorphous alloy. In the crystallized sample prepared by annealing the as-quenched amorphous alloy for a long time in a supercooled liquid region, the precipitated phases have been determined to be Zr₂Ni and Zr₆Ga₂Ni by analyzing the energy-differential intensity profiles at Zr, Ga and Ni K absorption edges.

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When KCl is cooled rapidly from the melt, there occurs a complicated crystal growth and several KCl single crystals are obtained in the crucible. The author has studied several properties of the crystal fragments mainly from the macroscopic point of view. In this paper, a model is treated on the morphology of the crystal growth in special reference to the growth only in high growth rate direction, as follows. The propagation of growing surface is analyzed when the melt is solidified under a constant supercooling and a constant cooling rate conditions, and then the periodic steplike growing surface and the spacing between the subgrain boundaries determined by the physical circumstance are examined. The models of the crystal growth condition as approximations of the actual growth are proposed and the propagation of subgrain boundary is also discussed. Furthermore, these results are confirmed by the observation of the crystal.

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The authors have studied the preparation of amorphous Ni–Co–B alloy films to be electrodeposited with a rotary electrode, in comparison to the conventional static bath method. The structures of such films have been also studied, and the following conclusions are obtained.
Using the rotary electrode, amorphous alloy films can be prepared with a formation range approximately 10 times wider than the extremely narrow range allowed by the conventional static bath method.
The optimum peripheral speed of the cathode is 70 cm/s for the preparation of amorphous alloy films by means of the rotary electrode.
The content of hydrogen in such a film becomes higher than that prepared by the static bath method. Alloying of the hydrogen appears to be related with the non-crystallization or formation of finer crystal grains in the film, in comparison to the static bath method.
Intermetallic compound CoB is formed between the substrate and the amorphous alloy film.

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Reactive diffusion of the Pt–Si system has been studied by using bulk Pt/bulk Si single crystal diffusion couples in the temperature range from 673 to 923 K in an evacuated atmosphere of 10⁻² Pa. To study the effect of the atmosphere on the growth rate of the diffusion layers, some diffusion couples have been annealed at 673, 873 and 923 K at a pressure 10⁻⁵ Pa. The experimental results were compared with the previous results obtained by using Pt thin film/bulk Si diffusion couples.
In the bulk Pt/Si diffusion couples annealed at 673 K for 3.6 ks or more, Pt₂Si and PtSi have been found. The silicides, Pt₃Si, Pt₇Si₃ and Pt₆Pt₅ were formed above 723 K. All of them grew satisfying the parabolic law.
The interdiffusion coefficients of PtSi and Pt₂Si in bulk samples almost coincide with the minimum values for thin film diffusion couples, respectively, in spite of a general recognition that interdiffusion in thin film diffusion couples can occur faster than in bulk sample at low temperature.
This result partly supports our previous result of reactive diffusion in the Ni–Si system that any apparent difference between the diffusion phenomenon in bulk and thin film diffusion couples could not be found.

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Effects of the quenching temperature on the intragranular and cellular precipitations in a Cu-1.5%Be alloy on aging at 523–593 K were studied by hardness measurement, optical and electron microscopic observations, and electrical resistivity measurement. The intragranular precipitation was accelerated with increasing quenching temperature. Especially the formation of G.P. zones and the γ″ phase was accelerated. The reason was explained by the increase in the vacancy concentration needed for the diffusion of the Be atom. The cellular precipitation was suppressed with increasing quenching temperature.

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The experimental results on stress relaxation show that in a certain range of temperatures and strain rates many dilute solid solutions, both interstitial and substitutional, exhibit a distinct transition from concave upward to concave downward logσ-log\dotε curves. This behavior is related with the Portevin-Le Chatelier effect as was described by Van den Beukel. The stress relaxation curves are described by a physical model, presented in an earlier paper, which includes specific mechanism for dislocation motion, for the internal structure and for the interaction between impurities and dislocations. The model is tested on a Cu-0.2 at% Zn alloy in the present work. Several microscopic parameters, such as the activation energy for the migration of the impurity, the binding energy between impurities and dislocations, the jog concentration and the index m+β in Van den Beukel’s approach, are obtained from a fitting of the entire stress-relaxation curves to the model. The experimental evidence is in agreement with that from the onset of serrated yielding.

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Hydrogen and deuterium trapping sites in high-strength steels have been observed by secondary ion mass spectrometry (SIMS). High-strength steels with 1400 MPa tensile strength are stressed and dipped in D₂O and 20% NH₄SCN solution at 323 K to occlude hydrogen and deuterium. Depth profiles by SIMS show the presence of deuterium, which indicates hydrogen trapping sites occluded during the delayed fracture test. Secondary ion image analysis by SIMS has made it possible to observe hydrogen and deuterium trapping sites in high-strength steels. Hydrogen tends to accumulate at grain boundaries, in segregation bands, and on inclusions. Line scans by SIMS have shown that the accumulation ratios of hydrogen for the grain boundaries, segregation bands of P and inclusions are 7.8, 5.0 and 11.0 times higher than that in the matrix, respectively. Hydrogen trapping sites at the grain boundaries can be observed by measuring within 24 h after the delayed fracture test.

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High temperature deformation and microstructural evolution were studied in tension using single phase polycrystalline Ni₃Al doped with boron. The samples with grain sizes from 3.0 to 18 μm were rapidly H₂ gas-quenched immediately after straining in order to examine deformed structures and to elucidate the mechanism of superplastic deformation. A stress peak appears at a strain of less than 0.1 more remarkably with increasing initial grain size, and with increasing strain rate or decreasing temperature. Dynamic recrystallization (DRX) initiates along prior grain boundaries at near the peak stress and develops toward grain interiors on further deformation, leading to the evolution of necklace structures. A rapid decrease in flow stress after the peak is mainly due to grain boundary sliding at interfaces between DRX grains. In contrast, work hardening takes place at low and moderate strains for samples with smaller initial grain sizes, when they are deformed at lower strain rates or higher temperatures. Under these conditions, grain boundary sliding occurs predominantly accompanied with grain coarsening due to DRX. Superplastic elongation appears in specimens exhibiting no significant behavior of work softening or work hardening. It is concluded that work softening or hardening behavior depends sensitively on the relative difference between the initial grain size and the stable DRX grain size evolved at high strains, and high temperature deformation of Ni₃Al can be controlled by grain boundary sliding assisted by DRX.

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A new method (Tangent method) was proposed for the determination of the effective valence of impurity element that is one of the most important factors for the evaluation of the effectiveness of solid state electrotransport (SSE). The Tangent method can eliminate several disadvantages in the traditional methods. For the confirmation of the Tangent method, the Fe–C and Fe–N systems are picked up as model systems, because the thermodynamic properties of these systems have been well established and there are many reports on the SSE process of these systems. The present experimental studies have been conducted under the following conditions: initial uniform carbon content=1300 mass ppm, nitrogen one=270 mass ppm, temperature=1273 K and current density=3∼5×10⁶ Am⁻².
The measurements show good reproducibility and the following results were obtained:
(i) +3.7 and +3.1 were obtained as the effective valences of carbon and nitrogen, respectively.
(ii) These values are in good agreement with the ones measured by traditional methods.
(iii) The values of diffusion coefficient of carbon and nitrogen in γ-iron, which were obtained in the combination of the Tangent method and the traditional unsteady state method, agree well with the values in the literature.

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Graphite furnace atomic absorption spectrometry (GF-AAS) using direct atomization of the acidic sample solution was studied to establish a rapid and sensitive determination procedure of trace selenium in nickel-base heat-resisting alloys. The interferences of matrix and co-existing elements were minimized by using the stabilized temperature platform furnace (STPF) method in combination with alternating current Zeeman background correction, and thereby the sensitivity of GF-AAS in selenium determination was significantly improved. The detection limit (3σ of blank value) was 23.5 pg, which corresponded to 0.12 ppm selenium when the weight of sample was 0.5 g. The proposed procedure can be applied to the determination of selenium in nickel-base alloys without pretreatment of the sample solution and also calibration with solid standard samples or by standard additions.

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A series of melting and solidification experiments were carried out using high-purity SiO₂ and Al₂O₃ powders as the starting materials. The effect of melting temperature on the morphology of the primary mullite was investigated. The following conclusions were made:
1) The morphology of the primary mullite went through five stages as the melting temperature increased; massive, fibrous, faceted dendritic, feathery and fine feathery structures. These phenomena can be explained based on the number of effective nuclei in the melt.
2) The fibrous mullite grew from mullite precursors formed in the melt. Under highly supercooled conditions, the fibrous morphology becomes unstable and begins to branch and form a faceted dendritic crystal.
3) When the number of nuclei is extremely small, the mullite nucleated on the rhombic dodecahedron Mo originating from the molybdenum crucible and crystallizes out into a feathered structure.

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In the present study, medium carbon steel has been hot dip aluminized (HDA) typically at 973 K/1–2 m, as well as calorized (CAL) by a cementation process, typically 1173–1223 K/2–4 h in a controlled atmosphere. It is found that in HDA coatings, the outermost pure Al layer is followed by predominantly hard intermetallic phases such as FeAl₃ and Fe₂Al₅, the latter forming a serrated interface with the base. In CAL coatings, depending upon the process parameters (such as pack composition, temperature and time of calorizing), phases such as FeAl and Fe₃Al form predominantly and the other Al-rich phases are presented to a lesser extent.
Since the HDA presents a quasi-equilibrium situation with regard to phases formed between the base metal and the Al-coating (in view of the very short time of treatment), an attempt has been made to study the phase changes accompanying subsequent isothermal holding (773–933 K/10 m). This leads to the formation of stable equilibrium phases, possibly Fe₃Al and solid solution next to the base, resulting in improved endurance to thermal shock (1123 K/WQ) and bending. In the CAL process, parameters have been optimised to produce a mixture of favourable phases, as defined by Pilling-Bedworth parameter.

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Cu-based amorphous alloys containing above 80 at%Cu are found to form in the Cu–Mg–Ce ternary system by rapid solidification. The composition range extends from 8 to 14 at%Mg and 4 to 8%Ce. No amorphous phase is formed in the Cu-rich Cu–Mg and Cu–Ce binary systems and hence the simultaneous dissolution of the three elements with significantly different atomic size ratios is essential for the glass formation. The increase of the glass-forming ability in the ternary system has been interpreted to be due to the difficulty of nucleation and growth reactions of crystalline phases through the formation of a higher degree of dense random packed structure. The crystallization for the Cu–Mg–Ce amorphous alloys takes place through two stages of Am→Am′+Cu+Cu₆Ce→Cu+Cu₆Ce+Cu₂Mg in the range above about 84 at% Cu and Am→Am′+Mg₂Ce→Mg₂Ce+Cu+Cu₆Ce+Cu₂Mg in the range below 80 and 83 at% Cu. The Cu-based amorphous alloys exhibit a color tone typical for crystalline Cu metal and are expected to develop as an amorphous alloy with the distinguishable color.

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A multicomponent Fe₇₂Al₅Ga₂P₁₁C₆B₄ alloy was found to form a glassy phase with a wide supercooled liquid region before crystallization and of ferromagnetism at room temperature. The glass transition temperature (T_g), crystallization temperature (T_x) and temperature intervals of supercooled liquid, ΔT_x(=T_x−T_g) for the glassy alloy are 732, 793 and 61 K, respectively. It is to be noticed that the supercooled liquid region exceeds 60 K which is about 3 times larger than the largest ΔT_x value for the Fe-based glassy alloys reported up to date. The amorphous alloy also exhibits good bending ductility and rather good soft ferromagnetic properties at room temperature. The soft magnetic properties are improved by annealing at temperatures above the Curie temperature (T_c). The magnetic properties at room temperature for the glassy alloy annealed for 600 s at 723 K are 605 K for T_c, 1.07 T for saturation magnetization, 5.1 A/m for coercivity, 9000 for permeability at 1 kHz and 2.0×10⁻⁶ for magnetostriction. The finding of the ductile Fe-based glassy alloy exhibiting simultaneously the wide supercooled liquid region and good soft ferromagnetic properties is expected to create a new ferromagnetic bulk material with good deformability.

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Bulk glassy Zr₅₅Al₁₀Ni₅Cu₃₀ alloys in a cylindrical form with a diameter up to 16 mm and a length of 70 mm were produced by sucking the molten alloy into a copper mold. The sucking force was generated from the rapid movement (5.0 m/s) of piston with a diameter of 16 mm which was set at the center of the copper mold. The sucking velocity was evaluated to be as high as 6.3 kg/s. Neither cavity nor hole is seen on the outer surface of the bulk glassy alloy and the glass transition temperature (T_g), crystallization temperature (T_x) and supercooled liquid region defined by ΔT_x(=T_x−T_g) are the same as those for the melt-spun glassy ribbon with a thickness of about 30 μm. Furthermore, there is no appreciable difference in T_g, T_x and ΔT_x over the whole cast sample. The tensile fracture strength is 1620 MPa which is comparable to the compressive strength. The fracture takes place along the maximum shear plane and the size of the veins is about ten times as large as that for the melt-spun glassy ribbon. The significant difference indicates that the deformation for the cast bulk alloy takes place over the thicker and wider region. Thus, the direct production of the bulk glassy alloy with good deformability by the suction casting method is important for the future development of bulk glassy alloys.

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Ferroelastic domains with incommensurate twinning planes are observed for LaNbO₄ crystals by AFM. It is found that each band on twinning boundaries has a fine surface structure composed of a shallow groove and a few striae, and many parallel stripes in the region between these two bands, which are shown by high resolution POM, are not detected. Relation between the band and the domain wall, and origin of the stripes are discussed.

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