The activated flux coated wires are used to examine the effect of the fluxes on the weld penetration of the magnesium alloy. A series of emission spectroscopy of arc plasma for TIG welding for magnesium with normal wire and activated flux coated wire are developed. It is found that intensities of emission spectra of Mg I increase significantly when the flux wires are used. All the flux coated wire can increase the weld penetration of the TIG welding. The electron temperature and electron density of welding plasma are estimated. The result indicated that the electron temperature of arc plasma decrease when the flux coated wires are used; on the contrary, the electron density of the plasma got enhanced. It is believed that the current density increases with the electron density increase, which is one of the reasons that the penetration depth increase when the flux wires are used.

The influences of Cu addition upon structure and magnetic properties of as-quenched Fe_87−xZr_3.5Nb_3.5B₆Cu_x ribbons are investigated. An appropriate content of Cu addition improves the nucleation of α-Fe through increasing the number-density of nucleation sites in as-quenched Fe_87−xZr_3.5Nb_3.5B₆Cu_x ribbons. However, at high Cu dopants (x≥3.5) the nucleation effect of α-Fe becomes weak, possibly connected with the reduction of effective number-density of Cu clusters due to the coarsening effect of them. Among as-quenched Fe_87−xZr_3.5Nb_3.5B₆Cu_x ribbons prepared with a wheel speed of 35 m/s, the as-quenched Fe₈₄Zr_3.5Nb_3.5B₆Cu₃ (x=3) ribbon with the largest permeability (2.4×10⁴ at 1 kHz) and saturation magnetic induction (1.18 T), possibly has the highest number-density of Cu clusters which can serve as nucleation sites for α-Fe grains.

The morphology and crystallography of sub-blocks in lath martensite were studied in an interstitial free steel. In each block the sub-blocks are classified into dominant and minor sub-blocks in terms of the volume fraction. The orientation relationship between the dominant and minor sub-blocks is [011]α′/10.5 degrees. Minor sub-blocks have a plate-like morphology and are connected to each other with the habit plane close to {111}γ, and their growth directions close to ⟨10\\bar1⟩γ.

Deformation twinning, which is extremely difficult to produce in face-centered cubic (FCC) crystals with medium to high stacking fault energy (SFE), was observed in pure copper single crystals with an appropriate crystallographic orientation subjected to equal-channel angular pressing (ECAP) for one pass at room temperature. Dense shear bands were also observed, delineated by large-angle grain boundaries, and with close to a twinning relation with the matrix, suggesting the role of deformation twinning at their nucleation sites. The activation of deformation twinning is rationalized by a favorable crystallographic orientation and predominant dislocation density in a primary slip system.

The bore expansion tests of a mild steel sheet and two types of high-strength steel sheets using conical- and flat-headed punches are simulated using the dynamic explicit finite element program LS-DYNA ver. 970 with shell elements. The ductile fracture criterion proposed by Cockcroft and Latham is applied to the prediction of the forming limit in bore expansion processes. In our previous studies, the fracture strains derived from the criterion gave the best fit to the experimental results in biaxial stretching. The comparison of the simulation results with the experimental results in this study shows the possibility of forming limit prediction via the present approach in which we take the work hardening and damage in the blanking process of the bore into consideration.

The ferritic ductile iron (FCD400) is widely used as industrial material. As regards to its high temperature application, fatigue at elevated temperature, and advanced mechanical properties has been investigated and clarified. In low cycle fatigue (LCF), the S-N curve is presented by the relation of plastic strain to the number of cycles as fatigue life, which can be predicted by the Manson-Coffin model. In this model, the ductile index is appointed as a material constant of 0.5 and the ductile coefficient is related directly to the so-called plastic deformation capacity of the material. Namely, the low cycle fatigue life shall be dominated by the elongation rate. Concerned with it, one of authors reported that the elongation-to-fracture is 20% at room temperature, but reduces to about 9% at 473 K. This temperature is just within the range of dynamic strain ageing (DSA), which is the phenomenon of fluctuating stress due to mobile atoms in solid solution. So, in this study, strain controlled high temperature LCF-tests were carried out on ferritic cast iron at 473 K in air and the result is compared with those performed at room temperature, aiming to clarify the effect of elongation or DSA on the fatigue life. Particularly, this paper mentions about DSA effect to cyclic stress and cyclic plastic strain that causes contradiction of Manson–Coffin’s model in “the plastic strain range versus number of cycles” and “the stress range versus number of cycles” between room temperature (293 K) and 473 K. The fatigue life time at 473 K is 175 cycles lower than that at 293 K for all stress levels. However, DSA phenomena did not occur at high strain in 473 K cyclic fatigue test although it cannot be observed in tensile tests at 473 K. Based on the Manson-Coffin rule, the parameters (C_p=0.09 and 421, n=0.65 and 0.89 at T=293 and 473 K, respectively) for the fatigue life time prediction have been determined.

Friction stir processed (FSPed) aluminum alloys generally exhibit good mechanical properties pertaining to the textural feature, dynamic recrystallization (DRX), aging effect and are commonly accompanied by a thermal mechanical affected zone (TMAZ), and these are important metallurgical factors which cause inhomogeneous deformation problems. Therefore, a 1050 aluminum alloy sheet was used to eliminate the aging effect on the microhardness distribution and tensile properties. From the microhardness profile, a significant data fluctuation variation and microhardness drop could be recognized as the feeding speed slowed to 1.1 mm/s. It is reasonable to suggest that this is closely related to the subtle microstructural changes of dynamic recrystallized grains which were a consequence of the friction stir process heat input.
In addition, a significant {110}⟨001⟩ crystal aggregation was observed in the center of SZs of O-FSPed samples, where ⟨001⟩ aligned closely along the processing direction (PD) while ⟨110⟩ aligned along the transverse direction (TD). The higher Taylor factors of the O-FSPper specimens were responsible for higher flow stress than that of the O-FSPpar specimens. One the other hand, the revolutionary pitch is an insignificant factor for tensile properties.
Experimental results imply that FSP possesses great potential to improve the formability especially of cold-rolled H14 tempered sheets, as a partial modification method when a proper feeding speed is properly selected.

Cold rotary forging is an advanced but very complex incremental metal forming technology with multi-factors coupling interactive effects. The contact patterns between the upper die and workpiece have an essential effect on the cold rotary forging process. In the current work, a 3D elastic-plastic dynamic explicit FE model of cold rotary forging of a cylindrical workpiece is developed under the ABAQUS software environment and its validity has been verified by an experiment carried out on a T 200 cold rotary forging press. On the basis of this reliable 3D FE model, numerous simulation calculations have been carried out and it has been found that there are three new plastic deformation behaviors of cold rotary forging under three different contact patterns. With the first pattern, the middle part of the cylindrical workpiece is first penetrated axially from the upper surface to the lower surface by the plastic deformation zone (PDZ), and then the PDZ gradually develops radially towards the cylindrical surface until the entire cylindrical workpiece has become the PDZ. In the second situation, the PDZ gradually penetrates the axial height from the upper surface to the lower surface of the cylindrical workpiece. In the third situation, the upper region of the cylindrical workpiece is first penetrated radially from the cylindrical surface to the centre, and then the PDZ gradually develops axially towards the lower surface until the entire axial height has been penetrated completely. On the basis of these behaviors, the effects of three different contact patterns on the cold rotary forging process have been comprehensively investigated. The results of this research not only provide valuable guidelines for the design, installation and adjustment of dies in the cold rotary forging process, but also help to further understand the deformation mechanism of cold rotary forging.

Effects of B and Cr additions on magnetostriction and the mechanical properties of polycrystalline Fe₈₃Ga₁₇ alloy were investigated. Small addition of B increased magnetostriction of Fe₈₃Ga₁₇ alloy slightly, and improved the room temperature ductility and tensile strength significantly. The elongation and tensile strength of the (Fe₈₃Ga₁₇)₉₉B₁ alloy increased to 3.56% and 548 MPa compared with that of Fe₈₃Ga₁₇ alloy respectively. The Cr addition was shown to improve the room temperature mechanical properties of Fe₈₃Ga₁₇ alloy beneficially. The maximum magnetostriction of (Fe₈₃Ga₁₇)₉₈Cr₂ alloy was 70×10⁻⁶. The influences of B and Cr additions on the fracture mode of Fe₈₃Ga₁₇ alloy were also studied in this paper.

Aluminumtriethoxide were obtained when aluminum powder was refluxed in dehydrated ethanol containing aluminum chloride for 10 ks. It is shown that aluminumtriethoxide powder made in our laboratory coincided with that supplied in commercial market by similar pattern of XRD-analysis, particle size distribution analysis and particle morphology observation. It is considered that aluminumtriethoxide in our laboratory was electrochemically interpreted as corrosion product which has been oxidized in ethanol containing aluminum chloride as catalyst.

IrO₂/Ti-supported γ-MnO₂-type Mn-Mo-W triple oxide anodes were prepared by anodic deposition in MnSO₄-Na₂MoO₄-Na₂WO₄-H₂SO₄ solutions. The performance of anodes for oxygen evolution reaction during electrolysis of 0.5 kmol m⁻³ NaCl solution was examined at 1000 Am⁻². The stability, kinetics and physicochemical properties of the oxide deposit anodes were characterized by iR-corrected galvanostatic polarization, gravimetric, X-ray photoelectron spectroscopy and X-ray diffraction techniques. The addition of tungsten to the Mn-Mo oxide enhanced the oxygen evolution efficiency of anodes. The anode prepared in 0.2 kmol m⁻³ Mn²⁺-0.003 kmol m⁻³ Mo⁶⁺-0.006 kmol m⁻³ W⁶⁺ electrolyte of pH 0 showed the best performance among anodes prepared in this work. The high performance was attributed to the formation of single phase triple oxide with optimum composition, thickness and defect concentration. Tungsten addition beneficially exerts its effect via increasing the electrical conductivity of oxide deposits. The deposition mechanism of the oxides was discussed in terms of stability and population of Mn³⁺ species at the anode/electrolyte interface.

The fabrication of solar cell grade silicon (SOG-Si) feedstock involves processes that require direct contact between solid and liquid phases at near equilibrium conditions. Knowledge of the phase diagram and thermochemical properties of the Si-based system is therefore important for providing boundary conditions in the analysis of processes. A self-consistent thermodynamic description of the Si-Ag-Al-As-Au-B-Bi-C-Ca-Co-Cr-Cu-Fe-Ga-Ge-In-Li-Mg-Mn-Mo-N-Na-Ni-O-P-Pb-S-Sb-Sn-Te-Ti-V-W-Zn-Zr system has recently been developed by SINTEF Materials and Chemistry. The assessed database has been designed for use within the composition space associated with SoG-Si materials. The thermochemical database has further been extended to calculate the surface tensions of liquid Si-based melts. In addition to thermochemical and phase equilibrium calculation, several surface-related properties (temperature and composition gradients, surface excess quantity etc.) are able to simulate simultaneously using the database. The databases can be regarded as the state-of-art equilibrium relations in the Si-based multicomponent system.

The effect of continuous rotation evolutional control (CREO) on the pitting corrosion resistance of anodized Al-Mg alloy was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl₃ and by surface analysis. The potentials for pitting corrosion of anodized Al-Mg alloy was evidently shifted to the less noble direction by CREO and the time required before initiating pitting corrosion was shorter with CREO, indicating that the corrosion resistance with CREO was worse than without. The precipitates of Fe-Al intermetallic compounds remained in anodic oxide films of Al-Mg alloy. Cracks occurred in the anodic oxide films through the precipitates during initial pitting corrosion. The pitting corrosion was accelerated by cracks. The internal stress present in the anodic oxide films of the alloys with CREO was higher than without. It is assumed that the pitting corrosion is promoted by these cracks as a result of the higher internal stress resulting from the CREO.

Nanopatterns can be structured using either dry-etching or wet-etching. In this study, Ag/Si thin film was used to prepare the nano-hollow structures using the two step selective etching method (dry-wet etching, DWE). The etching scale was controlled by the layball process and a Focus Ion Beam (FIB) was used to investigate the DWE mechanism. Increasing the beam current of dry-etching raised the height of nano prominent structures, but deteriorated the interface of Ag/Si film, and even damaged the Ag film because of Ga⁺ bombardment. Regardless of the Ag nanoshape deposition, the residual Ag films were doped with Ga⁺ and were sensitive to DWE. After wet-etching, a nano hollow formed and the Ag films sunk. However, Ag_Ga (Ag film doped Ga ions) sidewall films formed due to the concentration gradient and the oxidative potential and this increased the volume of microporous phases, resulting in a reduction in the depth. Also, 15–30 nm Ag nano-particles were able to enhance the DWE mechanism in the Ag/Si nanostructures.

The extend forging process is divided into the initial reduction, performing process (square process) and the finish forging process, and so on. High productivity and dimensional accuracy are desirable features in the finish forging process. In this paper, the relationship between forging conditions and dimensional accuracy was investigated in the finish forging process. The cross-section is deformed from square to octagon by a pair of flat dies, and from octagon to round by a pair of tap dies in the finish forging process. The equations for prediction of the width were developed using a numerical simulation, and a process design method in which the target size is achieved in 4 passes was developed in the octagon process. The width size of predictions using this method and the actual measurement width size were compared, and the accuracy was verified. As a result, it was clarified that the actual width size was predictable within 10 mm. The influence of the feed, the rotation angle, and the octagon size on dimensional accuracy was investigated in the spiral forging. The actual improved experimental conditions were decided on as a result of determining the improvement forging conditions using a numerical simulation. The results of the improved conditions were compared with the conventional ones. By using a numerical simulation, the optimum conditions for forging the octagon to the target round shape were calculated. Both satisfactory dimensional accuracy and productivity were achieved compared with the conventional conditions.

Ti-20 mol% Al (Ti-12.3 mass% Al) alloy was diffusion-bonded to high carbon steel (0.82 mass% C) at 1273 K for 3.6 ks in a vacuum. The joint had a space of a few micrometers in thickness between the Ti-20 mol% Al alloy and the steel, and several specimens separated near the interface promptly after the bonding treatment. This phenomenon is referred to as ‘interface separation’. This paper describes the influence of heating temperature on the interface separation. Diffusion bonding of the Ti-20 mol% Al alloy to the high carbon steel was carried out at 1173 to 1423 K for 0.9 to 3.6 ks in a vacuum, and then several joints were heated at a given temperature for up to 176.4 ks in an evacuated silica tube. At 1173 K, the separation phenomenon could not be confirmed even after prolonged heat treatment. This joint had four kinds of reaction regions in the vicinity of the interface, and their thicknesses increased in proportion to square root of holding time. On the other hand, the joint bonded at more than 1273 K showed the separation at the interface. As the heating temperature increased, the holding time required to induce the phenomenon became shorter. To clarify a time when the separation occurs in the diffusion bonding process, the joint with a special shape was prepared and quenched into the water from 1273 K. The generation of voids was recognized at the interface. These results suggest that the occurrence of the interface separation is associated with interdiffusion between the Ti-20 mol% Al alloy and the steel.

A porous alumina with cylindrical pores was fabricated by unidirectional solidification in pressurized H₂ or H₂-Ar mixed gases using alumina feed rod with 15%SiO₂-Al₂O₃ composition. The effect of silica additive on the formation of pores during the solidification was investigated. The porosity of the samples increases with increasing hydrogen partial pressure under a fixed total pressure and decreases with increasing total pressure under a fixed hydrogen partial pressure. No cylindrical pores are formed under 10%H₂-90%Ar atmosphere. On the other hand, when the solidification is performed under 50%H₂-50%Ar or 100%H₂ atmosphere, the porosity and pore size for porous alumina fabricated using 15%SiO₂-Al₂O₃ feed rod are larger than those for the samples fabricated using 99.99%Al₂O₃ feed rod. Many small facet shape pores are formed due to vaporization of silica component on the cooling step during the solidification. When a solidification is performed under 10%H₂-90%Ar atmosphere using 15%SiO₂-Al₂O₃ feed rod, an excess hydrogen atom in the solid phase is lack to make the cylindrical pores due to decreasing the hydrogen solubility in solid phases by silica addition then, non-porous alumina is formed. As a result, the porosity for porous alumina fabricated using 15%SiO₂-Al₂O₃ feed rod is not proportional to square root of hydrogen partial pressure under a fixed total pressure.

For an electric conductor in a static magnet, electromagnetic vibration (EMV) is activated to take place when an alternating current flows through the conductor in the direction perpendicular to that of the magnetic field. Following the principle, in the present study we solidified the AZ91D magnesium alloys at various vibration timing moments and then examined the microtexture and microtexture. It is revealed that the decrease of the starting vibration temperature in the mushy zone results in coarse microstructures with large dendritic fragments and eventually with fully developed dendrites that are well oriented with their basal planes being perpendicular to the direction of magnetic field. It has been demonstrated that melt flow is responsible for structural refinement during EMV processing due to the electrical resistivity difference of the solid and liquid. In mushy zone, when vibration is imposed at a low temperature, the fraction solid of the primary phase prior to vibration has been large, which makes the semisolid slurry rather viscous. The intensity and scale of the melt flow is weakened and thus yielding coarse structures. Meanwhile, as the magnetic field is imposed throughout the entire experimental operation, the magnetization torque takes into effect to orient dendrites. The bridging of dendrites may have been accomplished at low vibration temperature before EMV is activated. In this case, the magnetization torque becomes predominant to align crystals along their preferential crystallographic orientation and thus resulting in highly oriented textures.

Bulk glassy alloy rods of diameters 18 and 20 mm were formed during the tiltcasting of Zr₆₀Al₁₀Ni₁₀Cu₂₀. A further increase in the rod diameter to 22 mm resulted in the formation of a mixed structure with approximately 60 vol% glassy phase and 40 vol% crystalline phase, which comprised the central region of the transverse cross-section of the alloy rod. The glass transition temperature (T_g), onset temperature of crystallization (T_x), and liquidus temperature (T_l) were measured to be 666 K, 768 K, and 1153 K, respectively, and the resultant ΔT_x (=T_x−T_g), T_g⁄T_l, and γ (=T_x⁄(T_g+T_l)) values were 102 K, 0.578, and 0.422, respectively. The high glass-forming ability of supercooled liquids is attributed to the high resistance of the liquids against crystallization due to the large ΔT_x and high T_g⁄T_l and γ values. For the alloy rod of diameter 20 mm, the Young’s modulus, yield strength, elastic strain, and plastic strain under a uniaxial compressive load are 80 GPa, 1820 MPa, 0.022, and 0.060, respectively; the plastic strain of the rod with diameter 20 mm is greater than that (0.04) of the glassy alloy rod of diameter 2 mm, although there exist no appreciable differences between their strength levels and fracture behaviors. The success of formation of the large-sized Zr-based bulk glassy alloy rod, which exhibits large plastic strains in conjunction with high strength levels, is promising with regard to further extension of the applications of such highly functional materials.

Titanium nitride (TiN_x: x=0.96–1.12) films were prepared by laser chemical vapor deposition (LCVD) using tetrakis-diethylamide-titanium (TDEAT) and ammonia (NH₃) as source materials. The effects of deposition conditions, mainly total gas pressure (P_tot), laser power (P_L) and pre-heating temperature (T_pre), on the composition, microstructure and preferred orientation of TiN_x films were investigated. The N/Ti ratios (x) in TiN_x films decreased with increasing P_tot and increased with T_pre at P_tot<400 Pa. The preferred orientation significantly depended on the T_pre and P_L. (111) orientation was obtained at T_pre<673 K and P_tot<600 Pa, whereas (200) orientation appeared at T_pre>673 K and P_tot<600 Pa. The increase in P_L caused the change from (200) to (111) orientation. With increasing T_pre, the TiN_x films changed from a faceted texture with (111) orientation to a square texture with (200) orientation.

In-situ observation of magnetic pulse welding process using a one-turn coil was performed by using a high-speed video camera. High-speed deformation and collision behavior of the metal plates were investigated. The flyer plate traveled toward the parent plate with a high speed by the generated electromagnetic force. A collision velocity of the flyer plate to the parent plate was 250 m/s at the representative welding condition (initial gap distance between two plates: 1.0 mm, discharge energy: 2.5 kJ). It was clearly observed that a part of the flyer plate which was located along the coil bulged toward the parent plate. The collision angle between metal plate surfaces was 0° at the initial collision point, but it increased continuously during the welding. Such a characteristic high-speed oblique collision is considered to result in formation of the wavy interface and gradual changes in its wavelength and amplitude along the welding interface.

Experiments were conducted to investigate the deformation behaviors and fatigue properties of a superelastic thin tube (SE-tube) and a high-elastic thin wire (HE-wire) of TiNi alloy under conditions of pulsating-plane, alternating-plane and rotating bending. The main results obtained are summarized as follows. (1) The stress-strain curve of the SE-tube in tension describes a superelastic hysteresis loop with an elastic modulus of 35 GPa. It is thus suited for use as a medical catheter tube with flexibility and shape recovery. The stress-strain curve of the HE-wire stays close to a straight line up to a strain of 4% and a stress of 1500 MPa with an elastic modulus of 50 GPa, and is suited for use as a medical guide wire with flexibility, high pushability and a good torque transmission performance. (2) With respect to fatigue, the SE-tube and the HE-wire in air both have a longer life in pulsating-plane than in alternating-plane and rotating bending, whereas the difference in fatigue life between alternating-plane and rotating bending is small. The relationship between the maximum bending strain and the number of cycles to failure in the region of low-cycle fatigue can be expressed by a power function for each kind of bending fatigue. The fatigue life in the body is longer than that obtained in air. (3) The maximum bending strain at the fatigue limit of the SE-tube is 0.8%–1.0% which is close to the starting strain of the stress-induced martensitic transformation. The maximum bending strain at the fatigue limit of the HE-wire is 0.7%–0.8%.

The Ti-6Al-4V alloy is a very attractive material for the fastener bolt of an aircraft because of its excellent combination of specific strength and corrosion resistance. However, poor workability and severe galling between work-piece and die material make it difficult to produce. The aim of the present work is to enhance the hot formability of the Ti-6Al-4V bolt. Multiple forgings were simulated using FE code to determine optimum process parameters including workpiece temperature, strain rate, and damage value. Various thermal oxidation treatments were investigated in order to prevent galling and increase the hot-workability. After the oxidation treatment, hot forging was conducted and the microstructure of forged specimens was investigated. Among the various heat treatments, holding at 750°C for 2 h provides the most homogeneous microstructure and a sufficiently low galling phenomenon after forging. Mass-gain versus time curves for isothermal oxidation were obtained in order to analyze the oxidation behavior.

The objective of this study is to develop a dental precision casting process for a beta-type titanium alloy, Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy which has been developed for biomedical applications, using a mold made by electrically fused calcia particles. The effect of a combination of different sizes of calcia particles on the surface condition of the mold was investigated. In addition, to obtain a smooth surface, a cast TNTZ was made using a mold made using a mixture of calcia particles with a wax pattern conducted with calcia slurry coatings. Furthermore, surface reaction layer of the cast TNTZ was evaluated using an optical microscopy, a Vickers’ hardness test and a X-ray diffractometry. The surface of the mold fabricated with a mixture of fine (diameter<0.3 mm) and coarse (diameter=1–3 mm) calcia particles is smooth and showed no cracks or defects. In addition, the surfaces of the cast TNTZ made using the duplex-coated wax pattern with the fine pure calcia slurry and crushed silica fiber-reinforced fine calcia slurry are very fine. Furthermore, the formation of the surface reaction layer on the cast TNTZ is remarkably inhibited. The results of this study should lead to enhancements in the creation of cast TNTZ for dental products.

Our previous study showed the noble MgNi intermetallic compound with a CuTi-type crystal structure could be synthesized from amorphous MgNi precursor under more than 5 GPa by high pressure synthesis and could be hydrogenated into novel hydride with a CsCl-type crystal structure at 355 K under 2 MPa of hydrogen. In this study, hydrogen absorption-desorption properties of the MgNi compound with CuTi-type structure were investigated. It was found that the MgNi with CuTi-type structure absorbed and desorbed hydrogen reversibly at 473 K. Effects of substitution of Ni by Cu or Ti in the MgNi compounds were also investigated. Ternary MgNi_1−xCu_x (x=0.2,0.5) and MgNi_0.9Ti_0.1 compounds were synthesized from amorphous precursors by high pressure synthesis. The MgNi_1−xCu_x (x=0.2,0.5) and MgNi_0.9Ti_0.1 have CsCl-type crystal structure. The lattice parameter of MgNi_1−xCu_x increased with increasing of Cu content. MgNi_1−xCu_x (x=0.2,0.5) and MgNi_0.9Ti_0.1 could be hydrogenated under hydrogen pressure of 2 MPa and the crystal structure of these hydrides were CsCl-type structure. The hydrogen desorption temperature of these hydrides decreased with increasing of amount of Cu or Ti substitution of Ni. The substitution of Ni by Ti in MgNi improved the hydrogen absorption capacity from 1.65 to 2.06 mass%.

High-pressure synthesis has been widely used for exploration of novel materials. In this study, Li-Y hydrides were explored under GPa-order pressure by using a cubic-anvil-type apparatus. Unfortunately, a novel hydride in Li-Y system was not synthesizedin this study, but it is found that 10 at% addition of Li can stabilize FCC-YH₃ high pressure phase even under ambient pressure. The Li added FCC-YH₃ have a CeH₃-type structure judging from the results of XRD and raman spectrometry and its lattice constant was estimated to be 0.52666(1) nm. Total hydrogen content of the hydride was estimated to be 3.52 mass%. This hydride was partially dehydrogenated at 575 K with decreasing its lattice constant down to 0.5206(1) nm. Then, the sample could absorb hydrogen again under 5 MPa-H₂ at 623 K. Hydrogenation enthalpy of the hydride was estimated from endothermic peak to |ΔH|=29.2 kJ/mol-H and this value is lower than that of YH₃ ambient pressure phase.

The phase transition of natural and synthetic ilmenite during oxidation by Cl₂ at 390–560°C was characterized. The ilmenite phase was converted to crystallographic shear (CS) phases during the oxidation. One third of the Fe²⁺ in the ilmenite phase was converted to FeCl₃. The remaining Fe²⁺ was oxidized to Fe³⁺ in the CS phases. The CS phase obtained from synthetic ilmenite was the Fe₂Ti₃O₉ (M₅O₉) phase. A small amount of Mg²⁺ impurity in natural ilmenite caused the resulting structure to be the M₁₃O₂₃ structure when it was oxidized to the CS phase at temperatures up to 490°C, with the M₅O₉ structure also formed at temperatures above 540°C. The presence of Mg²⁺ was crucial in determining the particular structure of the CS phase and its thermal stability. These observations provide a useful way to get an oxidation product with a particular structure of the CS phase. They showed that there can be significant effects on the phase transition and thermal stability of the products from the presence of an impurity element.

The material design tailoring of a synergistic effect of an in-situ nano secondary phase formation and deformation-induced nanocrystallization for improving the mechanical strength and ductility, has been investigated in Zr₆₅Al_7.5Ni₁₀Cu_17.5−xPd_x bulk metallic glasses (BMGs). As-cast Zr₆₅Al_7.5Ni₁₀Cu_17.5−xPd_x (x=5–17.5) BMGs have significant ductility in compressive deformation, which is attributed to deformation-induced dynamic nanocrystallization. The 10 at% Pd-containing BMG with a low volume fraction of the quasicrystalline (QC) phase of less than 6% exhibits increases in strength and Young’s modulus, in addition to a remaining plasticity of ∼5%, compared with the monolithic glassy alloy. Such improvements in the mechanical properties originate from the combination of two effects of in-situ homogeneous nano-QC formation and deformation-induced inhomogeneous nanocrystallization. The present method should be regarded as a new technique for the production of BMGs with high strength and good ductility.

We are so far involved in complete decomposition of organic wastes as well as volatile organic compounds (VOC) by the use of thermally generated holes in TiO₂. In view of the practical use of the present system, fixation of TiO₂ powders onto a substrate seems to be the core technology. To realize this, we have tried in the present investigation to fix powdered TiO₂ onto SUS meshes or Ni-Cr wires by means of electrophoretic deposition. We have constructed two kinds of equipment. One is a cartridge system which includes ten pieces of the mesh disk coated with TiO₂ that are arranged vertically. The other is a “heater-built-in” system with a triple-coaxial structure equipped with Ni-Cr/Cr₂O₃/TiO₂ wires. The former is used in combination with an external furnace; whereas the latter is a stand-alone system. Both systems exhibit excellent performance to completely decompose VOC into H₂O and CO₂.

Here we present a systematic study on the morphological deviation of ZnO nanostructure (from sheets to micro-flowers) by varying pH of the solution via precipitation method. In this regard, zinc nitrate hexa-hydrate, NaOH and hydroxylamine hydrochloride (NH₂OH·HCl) were used. The solution of all three compounds was refluxed at a very low temperature (60°C) for short time (20 min). The solution pH was calibrated from 6 to 12 by the controlled addition of NaOH and HCl. We have observed from FESEM (field emission scanning electron microscopy) that the morphology of ZnO microballs composed with thin sheets markedly varies from sheet (at pH=6) to micro-flower composed with sheets of zinc oxide (pH=10–12). Further the morphology and crystallinity were also studied by the TEM (transmission electron microscopy) and HR-TEM (High resolution transmission electron microscopy) and it’s clearly consistent with the FESEM observations. The FTIR spectroscopic measurement also confirms the compositional analysis of ZnO and it comes in the range of 475 to 424 cm⁻¹ which is a standard peak of ZnO. In addition to this, the amount of H⁺ and OH⁻ ions are found a key to control the structure of studied material and discussed in the growth mechanism.

Nanoparticles can be dispersed by different methods in order to completely utilize their unique material characteristics. This study uses a self-developed nanofluid synthesis system to produce a CuO nanofluid with good suspension stability and particle dispersion without additives. The prepared CuO nanofluid has an average particle size of 60 nm and a substantially improved size distribution. The effect of the electrical double layer on the stability of the prepared CuO nanofluid was experimentally assessed by studies using different concentrations and by rheological experiments. Furthermore, the relationships between the pH value and Zeta potential, hydrodynamic radius and Uv/Vis spectra of the prepared CuO nanofluids are also discussed. The experimental results show that the CuO nanofluid still maintains its Zeta potential at above 30 mV for longer than 6 months, indicating high suspension stability.

The synthesis of bioinert oxide films on pure Ti surfaces by a combined chemical-hydrothermal treatment was investigated. Pure Ti substrates were chemically treated with H₂O₂/HNO₃ to form a TiO₂ gel layer. The specimens were then hydrothermally treated with Zr(OH)₄ dispersed NH₃/CH₃CH(OH)COOH aqueous solution in an autoclave at 453 K for 12 h. As a result, ZrO₂-TiO₂ composite films were successfully produced on the surface, and the volume fraction of ZrO₂ in the film was found to gradually increase from the substrate to the surface. The graded ZrO₂-TiO₂ film suppressed the deposition of hydroxyapatite on the surface during soaking in simulated body fluid.

Bulk Fe₂B and Fe₃B alloys have been prepared by a self-propagating high temperature synthesis combining rapid solidification technique. The Fe₂B and Fe₃B alloys are composed of t-Fe₂B dendrite and ultrafine eutectic matrix with t-Fe₂B and α-Fe, and the dendrites are rounded by the matrix. The volume fractions of the dendrite of the Fe₂B and Fe₃B alloys are 90% and 20%, respectively. The fracture strength reduces from 3400 MPa to 2660 MPa with the increase of dendrite content, but the strain at fracture rises markedly from 3% to 19%. The result indicates that a small quantity of dendrites embedded in the ultrafine eutectic matrix can reinforce the ductility.

The influence of applied pressures on temperature distribution in punch/die/graphite/sample assembly during SPS current control mode operation was systematically investigated by coupling experiments and computer modeling. Combined experimental and numerical results showed that the peak temperature and the temperature difference existing between the sample and the die outer surface progressively decreased with increasing of applied pressure from 5 to 80 MPa. This behavior was attributed to the strong change of the electric and thermal contact resistances at the punch/die interface due to punch Poisson deformation.

We report the growth, crystal structures, and orientation relationships of nanoscale M₂O₃ (M=Gd, Nd) thin films on Si(111) substrates using molecular beam epitaxy. We find that the grown Gd₂O₃ and Nd₂O₃ layers share the cubic bixbyite structure, have single orientations, and are well crystallized. The epitaxial oxides are also found to be of threefold symmetry, having orientation relationships [111]_M2O3||[111]_Si and [1\\bar10]_M2O3||[\\bar110]_Si with respect to the Si substrates. Further investigations along in-plane direction show that the M₂O₃ layers are well matched to the double unit cell of Si substrates, with slightly negative mismatch for the Gd₂O₃ and positive for the Nd₂O₃.

A bending device used for SEM-EBSD systems has been developed by the authors, which enables one to intermittently observe changes in microstructures induced by deformation in the same viewing area. Alternate compression-tension loading was applied to a sheet specimen of AZ31B magnesium alloy by bending the specimen. Twins were formed by compression straining. They remained after un-loading. Applying tensile straining lead to the disappearance of all the twins. Most of twins were those of {10\\bar12} types. Anisotropy in mechanical properties of magnesium alloys would be affected by this twinning and de-twinning behaviors.

ZnO particles with a bottle-like morphology were synthesized by direct melt oxidation of a source material mixed with Al, Zn, and Au in air at atmospheric pressure. The particles were synthesized when the source material contained Au. Without Au, only ZnO particles with a tetrapod shape were identified. The bottle-shaped particles consisted of a well-defined hexagonal faceted micro-rod stem and a bottleneck. It is proposed that the bottle-shaped morphology forms through a vapor-solid growth mechanism as no catalyst was used during the synthesis process.

The aim is to develop an uninterrupted processing route to manufacture metal coils, so that the efficiency of production, as well as the quality of the product and the cost-efficiency can be improved. The traditional method of joining two metal sheets is by welding; however the welding process itself can easily introduce additional processing steps and pile up the cost of production. In the past, joining two metal sheets with identical composition by the rolling process has not been easy. The present study induces dissimilarity between two sheets, i.e. pre-heat treatment for one plate to result grain growth. Experimental results indicate that such introduction of dissimilarity between two metal parts can significantly improve the roll bonding process, not only making the joint much stronger than the traditional welding technique, this newly developed method can enhance the efficiency of the production of metal coils in industries.