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The out-of-plane magnetocrystalline anisotropy and magnetoelastic properties of series of epitaxially grown layers of Co2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5 (CFGG) Heusler alloys thin films deposited on MgO with chromium buffer layer were investigated by means of the ferromagnetic resonance (FMR), SQUID magnetometer, and by the strain modulated FMR technique. The magnitude of the magnetocrystalline anisotropy constant was found to decrease with increasing layer thickness. The change of the anisotropy is caused mainly by the surface effects. However, for some of the samples series, the change of chemical ordering with the change of the magnetic layer thickness was also observed. An additional silver buffer layer influence on the properties of the magnetic layer was also investigated. For all three of the investigated series of the Heusler alloys, i.e., CFMS without Ag, CFMS with Ag, and CFGG, the experimentally observed magnitude of the magnetoelastic constant increases with the increase of the magnetic layer thickness.

The local atomic structure near an Nb atom in a Ti–Nb binary β –Ti alloy single crystal was examined by means of X-ray fluorescence holography. In the single crystal, high density of the fine ω –Ti phase was homogeneously formed and was distributed in the β –Ti matrix phase by heat treatment. In the ω phase, the atomic displacement accompanying the ω phase formation is suppressed near Nb atoms. Thus, the atoms near an Nb atom tend to maintain the body centered cubic structure even in the ω phase, as Nb is a typical β –stabilizing element. The structural model near an Nb atom in the ω phase is similar to that of a collapsed ω structure. However, the degree of collapse is higher near an Nb atom than that far from it. This inhomogeneous displacement produces diffuse diffraction spots in selected area electron diffraction patterns of the ω phase.

The local atomic structure near an Nb atom in a Ti–20 at. %Nb alloy single crystal, which consists of the β, α′′ and ω Ti phases, was investigated by means of X-ray fluorescence holography (XFH). The atomic images were reconstructed in the vicinity of an Nb atom, which is one of the typical β stabilizing elements in β Ti alloys. Most atoms in the β Ti primary phase were reconstructed clearly. The atoms in the α′′ Ti martensite phase could not be reconstructed, because the α′′ Ti martensite has the crystal structure with low symmetry. Some atoms in the ω Ti fine precipitates were reconstructed successfully, although the amount of the ω Ti phase was much smaller than that of the β phase. An Nb atom and its first nearest neighbors tend to keep the BCC structure even upon the ω Ti phase formation.

Microarea self-propagating high-temperature synthesis (microSHS) was ignited by the heat of mixing generated at the boundaries between an Al matrix and TiNi particles during plastic deformation at room temperature. The temperature of the boundaries was rapidly increased by microSHS; the temperature elevation resulted in local melting of the TiNi particle and the surrounding Al matrix, because the heat of mixing was localized in the vicinity of the TiNi particle although the amount of the heat of mixing was limited. Since the amount of the local melting region induced by microSHS is restricted, not only major elements (i.e. Al, Ti and Ni) but also impurities were involved in the solidification followed by local melting. As a result, FeNi nanoprecipitates, which have not been reported in SHS studies, were formed by inclusion of Fe, initially included as an impurity in raw materials. The formation mechanism of FeNi nanoprecipitates is discussed based on reference to the Al–Fe–Ni ternary alloy phase diagram. ...

In this study, a Pd40Cu20Ge40 metallic glass has been introduced as a novel prototype of Pd-based metallic glasses. The Pd40Cu20Ge40 glass exhibits glass transition at 52 °C. The glass transition temperature reduced by the melting point of most glasses is roughly 0.5 or 0.6 but that of the Pd40Cu20Ge40 glass is only 0.36, which is considerably lower than those of other metallic glasses. Specific temperature measurement, microstructural observation, viscosity measurement and demonstration of viscous flow forming were performed to confirm that the novel material presented is a glass. From viewpoint of the constraint on the motion of molecules or clusters in glasses, new categorization of glasses has been proposed.

We measured the temperature dependence of the apparent specific heat of Cu55Hf25Ti15Pd5 glassy alloy (metallic glass) by a differential scanning calorimetry method during continuous heating, and investigated the structural relaxation and crystallization processes. The results of structural evolution obtained by transmission electron microscopy are discussed in line with the differential scanning calorimetry data. Kinetics of crystallization process of the supercooled liquid above the glass-transition temperature is also studied. This alloy shows a complex relaxation and crystallization processes which are discussed in the paper.

Radial and longitudinal variations in the Young's modulus of a Zr55Al10Ni5Cu30 metallic glass cylindrical rod were examined by means of nanoindentation. The metallic glass rod, 2.4 mm in diameter, was prepared using a novel mold-casting method designed to suppress crystallization resulting from the heterogeneous nucleation originating from slag covering a molten alloy. In this study, Young's modulus was measured using a multiple partial unloading technique with a spherical indenter. In general, it is assumed that the cooling rate of a metallic glass rod depends on the radius of its cross section. However, no significant difference was found in the measured Young's modulus.

The effect of Al content on superelastic properties of Ti751xNb15Zr10Alx (x = 0­6 at%) quaternary ¢ Ti alloys were investigated. And the effects of baking for coating or plating on superelastic properties were also studied. The alloys containing 3 and 4 at% of Al clearly exhibited superelastic behavior after aging at 453 and 553K, which are appropriate temperatures for industrial coating and plating, respectively. Ti72Nb15Zr10Al3 alloy exhibited the largest recovery strain of 2.5% due to superelastic behavior even after industrial coating and plating. In this quaternary alloy system, strange non-monotonical change of superelastic behavior as a function of Al content was also found. [doi:10.2320/matertrans.M2012184]

Precipitation of ZrCu with the B2 structure in Zr50Cu50–xAlx (x = 0, 4, 6) metallic glasses by rapidly heating and cooling was investigated. By rapidly heating and cooling, the ZrCu B2 phase precipitates the most in Zr50Cu46Al4 metallic glass plates prepared by tilt-casting without using a silica nozzle. The amount of the ZrCu B2 phase precipitated in Zr50Cu46Al4 metallic glass ribbons prepared by using a silica nozzle decreases by Si diffused from the silica nozzle during the preparation. This work is discussed from the viewpoint of crystallization behavior and why larger Zr-based bulk metallic glasses can be formed by suction, tilt, and cap casting without using a silica nozzle.

This paper reports the systematic investigation of vortex-type spin torque oscillation in circular disks of highly spin-polarized Co2Fe0.4Mn0.6Si (CFMS) Heusler alloys. We fabricated the current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices with various disk diameters (D) using the layer stack of CFMS/Ag3Mg/CFMS. The gyrotropic motion of the vortex core was successfully excited for the CFMS circular disks with 0.2 µm ≤ D ≤ 0.3 µm. The CPP-GMR device with D = 0.2 µm exhibited the Q factor of more than 5000 and the large output power of 0.4 nW owing to the high coherency of vortex dynamics and the high spin-polarization of CFMS. However, the Q factor was remarkably decreased as D was reduced from 0.2 µm to 0.14 µm. The comparison with the calculated resonance frequencies suggested that this degradation of the Q factor was due to the transition of the oscillation mode from the vortex mode to other modes such as the low-coherent out-of-plane precession mode. The present experimental results also suggest that there exists an adequate disk size for the enhanced Q factor of the vortex-type spin torque oscillation.

The origin of thermal stability and crystallization process of Zr50Cu40Al10 metallic glass have been investigated by means of differential scanning calorimetry (DSC), x-ray diffraction (XRD) and resonant ultrasound spectroscopy (RUS) techniques, by comparing to Zr70Cu20Al10 and Zr70Cu30 glassy alloys. The thermal stability of Zr50Cu40Al10 is significantly higher than those of the others. The x-ray diffraction analysis indicates that constituent atoms in Zr50Cu40Al10 are closely packed in a glassy state. It was found from DSC that Zr50Cu40Al10 glass shows a complicated crystallization process when it is heated at usual heating rates, but when it is rapidly heated, the ordered B2-type ZrCu (equilibrium phase higher than 984K) is formed as a primary phase. This behavior is discussed in terms of the long-range-diffusion of atoms.

We have investigated the origin of significantly high thermal stability of Zr 50 Cu 40 Al 10 metallic glass and its crystallization behavior as compared to Zr 70 CU 20 Al 10 and Zr 70 Cu 30 glassy alloys, by differential scanning calorimetry (DSC), x-ray diffraction (XRD) and resonant ultrasound spectroscopy (RUS) techniques. It was found from XRD and DSC analyses that (i) constituent atoms in Zr 50 CU 40 Al 10 are highly close-packed in a glassy state and (ii) Zr 50 Cu 40 Al 10 glass shows a complicated crystallization process when it is heated at conventional heating rates, but when it is rapidly heated, the ordered B2-type ZrCu is dominantly formed. The high thermal stability and its crystallization behavior are discussed in terms of the long-range-diffusion of atoms and elastic strain energy.

Viscous flow behavior in supercooled liquid region of as-cast and pre-annealed Zr55Cu30Al10Ni5 bulk metallic glasses has been examined by using a penetration viscometer under high-speed heating rate of 20, 200 and 400 °C/min. Applied load for the cylindrical-shaped penetration indenter with a diameter of 1 mm was varied from 0.049 N to 0.294 N. Viscosity was quite independent of these applied loads. By pre-annealing the bulk metallic glasses at 400 °C, the density of the glasses increased, while the viscosity and the activation energy for viscous flow in their soopercooled liquid decreased with the pre-annealing treatments. Corresponding measurements of the differential thermal calorimetry (DSC) have been also done.

Effect of ball-milling and shot-peening on a metallic glass Zr 55 Al 10 Ni 5 Cu 30 , which possesses a large supercooled liquid region, has been investigated by means of differential scanning calorimetry, x-ray diffractometry and transmission electron microscopy. Metallic glassy ribbons, powders and plates were prepared by melt-spinning, gas-atomizing and mold-clamp casting techniques, respectively. No structural changes were observed in both the ribbon and powder specimens by ball-milling for around 100 h; however, the powder specimens were crystallized by Fe contamination when they were ball-milled for 540 h. No structural evolution was also observed when the plate specimens were subjected to shot-peening, while crystallized plate specimens were easily amorphized by mild and short period shot-peening. These results imply high phase stability of the Zr 55 Al 10 Ni 5 Cu 30 metallic glass against deformation.

Microstructures and mechanical properties of Cu mold-cast Ti 50 Cu 25 Ni 15 Sn 5 Ta 5 and Ti 42 Zr 5 Cu 44 Ni 5 Ta 1 alloys were investigated by means of X-ray diffraction, electron microscopy and compressive testing. Ti 55 Cu 22 Ni 15 Sn 5 Ta 5 alloys form microscopic composites consisting of Ti-based metallic glass as primary phase and β-Ti phases, while Ti 45 Zr 5 Cu 44 Ni 5 Ta 1 alloys consisting of Ti-based metallic glass matrix and high density of nanocrystals dispersed in the matrix homogeneously. Ti 50 Cu 25 Ni 15 Sn 5 Ta 5 bulk composite alloys showed 1.6% of plastic deformation and 2200 MPa of 0.2% of proof stress. The alloys also exhibited work hardening because of the presence of microscopic crystalline phases. Ti 45 Zr 5 Cu 44 Ni 5 Ta 1 bulk alloys also deformed plastically after stress reached 2000 MPa without work hardening.

Ti45Zr5Cu45Ni5 metallic glasses in which Ta and Al were substituted for Cu were evaluated in terms of mechanical properties, thermal properties and microstructures in order to determine the factors contributing to an improvement in plasticity. Samples are examined by compression testing, differential scanning calorimetry, X-ray diffractometry and electron microscopy. Mold-cast Ti45Zr5Cu44Ni5Ta1 bulk specimens were confirmed to consist of a metallic glass matrix and nanocrystals homogeneously dispersed at high density within the matrix. The yield stresses of both Ti45Zr5Cu45� xNi5Tax and Ti45Zr5Cu45� xNi5Alx are approximately 1800 MPa, and the maximum plastic strain of 3.1% was obtained for the Ti45Zr5Cu44Ni5Ta1 specimen. The Ti45Zr5Cu45� xNi5Alx bulk specimens exhibited poorer plasticity due to the formation of larger crystalline grains. (doi:10.2320/matertrans.MF200616) Various kinds of Ti-based amorphous aloys and metallic glasses have been developed, 1-12) due mainly to the light weight and high corrosion resistance properties of Ti. Ti- based metallic glasses are therefore attractive candidates for light-weight, high-strength and biocompatible structural materials. However, fully metallic glasses exhibit only elastic deformation, and activation of many shear bands in metallic glasses is necessary for plastic deformation. The homogeneous dispersion of nanocrystals in metallic glasses is one method for preparing metallic glasses that undergo plastic deformation by the activation of shear bands. Recently, Ti-based bulk metallic glasses exhibiting plastic deformation have been reported, 6,11) although the micro- structures of the materials have yet to be clarified. If the plastic deformation in Ti-based bulk metallic glasses is caused by the dispersion of nanocrystals, it may be possible to increase the plastic strain by optimizing the density, distribution, and morphology of the nanocrystals. Many Ti alloys exhibit solid-state phase transformation from austenite � -Ti to martensite � 00 -Ti. Whenstabilizers are added to the Ti alloys, the martensite transformation temperature (� transus) decreases with increasingstabilizer content due to stabilization of the � -Ti phase. When such alloys are quenched, it is expected that � -Ti nanocrystals will precipitate. In the present study, Ta and Al asand � stabilizers were substituted for Cu in Ti45Zr5Cu45Ni5 and the resultant alloys were rapidly quenched to form bulk metallic glasses. The mechanical and thermal properties and micro- structures of the glasses were investigated with respect to the dispersion of nanocrystals. 2. Experimental Procedures Ingots with nominal compositions of Ti45Zr5Cu45Ni5, Ti45Zr5Cu45� xNi5Tax and Ti45Zr5Cu45� xNi5Alx (x ¼ 1; 2; 3; 4; 5) were prepared by Ar-arc melting, and cylindrical bulk specimens of 1 mm in diameter and 30 mm in length were prepared by Cu mold casting of the ingots. Differential scanning calorimetry (DSC) measurements were performed to determine the glass transition temperature (Tg), crystal- lization temperature (Tx), and supercooled liquid region (� Tx ¼ TxTg) at a heating rate of 0.67 K/s. The micro- structures of the specimens were characterized by X-ray diffractometry (XRD) using a rotating Cu anode, scanning electron microscopy (SEM), and transmission electron mi- croscopy (TEM). The mechanical properties of the speci- mens were examined at room temperature through compres- sion tests at a strain rate of 1 � 10 � 4 /s using an Instron-type machine.

The energy spacing between the spin-doublet bound state of _{Λ}^{4}He(1^{+},0^{+}) was determined to be 1406±2±2 keV, by measuring γ rays for the 1^{+}→0^{+} transition with a high efficiency germanium detector array in coincidence with the ^{4}He(K^{-},π^{-})_{Λ}^{4}He reaction at J-PARC. In comparison to the corresponding energy spacing in the mirror hypernucleus _{Λ}^{4}H, the present result clearly indicates the existence of charge symmetry breaking (CSB) in ΛN interaction. By combining the energy spacings with the known ground-state binding energies, it is also found that the CSB effect is large in the 0^{+} ground state but is vanishingly small in the 1^{+} excited state, demonstrating that the ΛN CSB interaction has spin dependence.

International audience; In order to test theoretical frameworks of the baryon–baryon (BB) interactions and to confirm the “Pauli effect between quarks” for the first time, we have proposed an experiment (J-PARC E40) to measure low-energy hyperon–proton scattering cross sections of the Σ^+p, Σ^−p elastic scatterings and the Σ^−p → Λn inelastic scattering in the momentum range of 400 < p (MeV/c) < 700 in the laboratory system. Experimentally, we detect two successive reactions of the Σ production (π^±p → K^+Σ^±) and the Σp scattering (Σp → Σp) in the same liquid hydrogen target. The former is measured with two magnetic spectrometers, and the latter with a scattered proton detector (CATCH). By using a high intensity π beam, we estimate that more than 10,000 scattering events can be identified. In this experiment, we aim to provide good quality scattering data to test the theoretical models of the BB interaction.

The cold drawing of cast Cu100� xZrx (x ¼ 3, 4 and 5 at%) alloys to the reduction ratio of 99.7% was found to cause simultaneous achievement of ultrahigh tensile strength of 1350 to 1800 MPa and high electrical conductivity of 30 to 45%IACS (International Annealed Copper Standard). The cold-drawn Cu95Zr5 alloy wire has a well-developed fibrous structure of fcc-Cu and tetragonal Cu9Zr2 phases. The volume ratio of the fcc-Cu phase was evaluated to be about 76%. A very high density of internal defects was observed inside the Cu9Zr2 phase in the cold-drawn Cu95Zr5 alloy. The microstructure data suggest that the Cu fibrous phase with high aspect ratios is the origin for the achievement of high electrical conductivity and the well-developed fibrous structure contributes to the high tensile strength. The success of synthesizing the Cu-Zr alloy wire with simultaneously high tensile strength and high electrical conductivity exceeding the best combination of all Cu-based alloys reported up to data is expected to be used as a new type of high-strength and high conductivity material because of some advantages of energy saving, low materials cost and simple production process. [doi:10.2320/matertrans.47.1595]

The Pd and Pd–Ni thin films with an fcc structure were prepared by sputtering. The films were immersed in the pure water and the hydrogen-dissolved water alternatively and the electrical resistance of the films was measured during the immersion. The Pd and Pd–Ni thin films possess good sensitivity to hydrogen dissolved in water. The electrical resistance of the films increases in the hydrogen-dissolved water and decreases in the pure water with excellent reproducibility. The electrical resistance change of the Pd–Ni alloy films is smaller than that of the Pd films. Nickel addition improves the response of increase/decrease of the electrical resistance during the immersion in the pure water and the hydrogen-dissolved water. The detailed electrical behavior of the films is investigated in this study.

Variant rearrangements induced by external magnetic field in Fe–Pd FCT martensite transformed from FCC austenite single crystals have been investigated by means of optical microscopy. Fe–Pd single crystals in fully martensite state contain two large correspondence variants, and a kink due to {1 0 1} twinning is observed at the twinning boundary of the variants. The twinning boundary exhibits both large reversible and small irreversible movement by applying magnetic field as a result of variant rearrangement, and 0.49% of reversible strain is obtained. The variant rearrangement is not completed even though magnetic flux density is increased to maximum of an electromagnet used. The boundary also moves reversibly by application of external compression stress, however, the direction of the boundary movement is opposite with respect to the movement induced by magnetic field and the variant rearrangment is not completed. The reversible strain of 2.8% was also observed when the specimen was compressed.

TiNi-based binary shape memory alloy thin films have been fabricated by means of simultaneous multi-target sputtering method. The films were deposited onto Cu foils by a D.C. magnetron sputtering system with two separate Ti and Ni targets. Deposition of the films was carried out by sputtering both targets simultaneously. Composition of the films was controlled by adjusting sputtering power for each cathode. The thin films were heat-treated at various temperatures for 1 h and then quenched into water. Microstructures of the films were characterized by scanning electron microscopy and transmission electron microscopy. Ti-50.5Ni thin films heat-treated above 700 °C for 1 h were perfectly crystallized, however, those heat-treated at 500 °C for 1 h were not crystallized completely. Fracture stress of the films heat-treated at 700 °C was higher than that of heat-treated at 500 °C. These results are quite different from the case of thin films deposited by sputtering a Ti-Ni alloy target. The brittleness of the films fabricated by simultaneous multi-target sputter-deposition originates in its deposition process.

A preparation method has been developed for thin foils for transmission electron microscopy (TEM) from powdered intermetallic compounds as a result of hydrogenation, in which powder samples are embedded in a Ni plate formed by electroless plating and then the assembly consisting of the Ni plate and the embedded powder samples are ion-milled. This method is successfully applied to some typical hydrogen-absorbing intermetallic compounds such as LaNi5, FeTi and TiMn2. In this method, Ni plating is carried out at ambient temperature, at which possible rearrangement of lattice defects that are introduced during hydrogenation is minimized and areas thin and wide enough for TEM observations are successfully produced because of the small difference in the sputtering yield between the Ni plate and these intermetallics. For thin foils produced by this method, not only lattice defects such as dislocations introduced into the bulk of powder samples can be characterized but also the crystallography of cracking and surface layers of powder samples can be characterized.

Tracer diffusion coefficient of 99Mo in α-iron has been determined in the temperature range between 833 and 1163 K by use of a serial sputter-microsectioning technique. The temperature dependence of the diffusion coefficient, D, in the whole temperature range of α-iron across the Curie temperature can be expressed by D= 1.48 +1.51 −0.75 ×10 −2 exp − 282.6±6.4 kJ mol −1 1+ 0.074±0.005 s 2 RT m 2 s − 1 where s is the ratio of spontaneous magnetization at T K to that at 0 K. The factor 0.074 in the above equation is smaller than 0.156 for self-diffusion in α-iron, showing that the influence of the magnetic transformation on the diffusion of molybdenum in α-iron is smaller than that on the self-diffusion as expected from the negative magnetic moment of molybdenum in the lattice of the ferromagnetic iron.

The relationship between microstructures and hydrogen absorption-desorption properties described in terms of pressure-composition (P–C) isotherms has been investigated as a function of the number of hydrogen sorption cycles. While the desorption pressure does not significantly depend on the number of cycles, the absorption pressure decreases as the number of cycles increases with the most significant decrease occurring between the first and second cycles. TEM observations reveal that numerous a -type edge dislocations are introduced during the first absorption cycles. Severe cracking occurs also during the first absorption cycle in such a way that the size of sub-particles delineated by cracks is comparable to that of particles observed after five cycles. The introduction of numerous lattice defects, such as a -type edge dislocations as well as the formation of severe cracks, is responsible for the significant decrease in absorption pressure between the first and second cycles, indicating that reproducible P–C characteristics of LaNi 5 can be achieved only when such numerous dislocations and cracks are formed in the bulk of LaNi 5 particles.

The generation of lattice defects and their effects on hydrogen sorption properties described in terms of pressure–composition ( P–C ) isotherms have been investigated as a function of the number of hydrogen sorption cycles for LaNi 5 and FeTi. For LaNi 5 , while the desorption pressure does not significantly depend on the number of cycles, the absorption pressure drastically decreases between the first and second cycles. Numerous dislocations of edge character with Burgers vectors of the 1/3〈1 2 10〉-type as well as numerous cracks are introduced during the first absorption cycle. The introduction of numerous lattice defects such as a -type edge dislocations and the formation of severe cracks seems to be completed during the first cycle, resulting in the reproducible P–C characteristics for the subsequent cycles. In contrast, FeTi exhibits ever-changing P–C characteristics with cycle number. The introduction of dislocations and cracks occurs during each of the absorption cycles. However, the extent to which this occurs is considerably smaller in each absorption cycle of FeTi than in the first absorption cycle of LaNi 5 . The difference in material response to hydrogenation seems to be closely related to the difference in ductility of these two intermetallics.

Ni2MnAl phase has the B2 crystal structure when an alloy was prepared at the moderate cooling rate. However, the crystal structure of Ni2MnAl oders from the B2 structure to the L21 structure by annealing at lower temperature than approximately 773 K. Ni2MnAl with the L21 structure exhibits martensitic phase transformation and ferromagnetic phase transition with decreasing temperature. On the contrary, Ni2MnAl with high Al content with the B2 structure exhibit no martensitic transformation but antiferromagnetic transition. With further cooling, Ni2MnAl with the B2 structure exhibit transition from antiferromagnetic phase to spin glass phase. Ni2MnAl with the B2 structure is suitable for developing a method to measure spin state of solids. [DOI: 10.1380/ejssnt.2011.331]

We carried out an experiment to produce the neutron-rich hypernucleus H-6(Lambda) via the (pi(-), K+) reaction on Li-6 target at the pion beam momentum of 1.2 GeV/c (J-PARC E10). In order to calibrate the scale of the missing-mass or of the Lambda binding energy of the hypernucleus, we also measured the C-12(pi(+), K+)(12)(Lambda)12, p(pi(-), K+)Sigma(-) and p(pi(+), K+)Sigma(+) reactions. The experiment was performed at the J-PARC Hadron Hall K1.8 beam line in December 2012 and January 2013. The overall collected data sample corresponds to an integrated beam intensity of 1.65 x 10(12) pions

Changes in microstructure and their effects on hydrogen sorption properties have been investigated as a function of the number of hydrogen sorption cycles in LaNi5 and FeTi. For LaNi5, while the desorption pressure does not significandy depend on the number of cycles, the absorption pressure drastically decreases between the first and second cycles. In addition to severe cracking and pulverization, numerous edge dislocations with Burgers vectors of the l/3 -type are introduced during the first absorption cycles. Both the introduction of numerous lattice defects and the formation of severe cracks seem to be completed during the first cycle, resulting in the reproducible P (pressure)-C (composition) characteristics for the subsequent cycles. In contrast, FeTi exhibits ever-changing P-C characteristics with cycle number. The introduction of dislocations with Burgers vectors of the -type in the form of tangles and cracks occurs during each of absorption cycles with the extent to which this occurs being considerably smaller in each of absorption cycles of FeTi than in the first absorption cycle of LaNi5. The difference in material response to hydrogenation seems to be closely related to the difference in ductility of these two intermetallics.

Microstructures and defect structures in intermetallic compounds in the La–Ni alloy system have been investigated by transmission electron microscopy in the composition range of La–77.8∼83.2 at.%Ni, which corresponds to compositions between two intermetallic phases, La 2 Ni 7 and LaNi 5. The intermetallic phase, La 5 Ni 19 of the Ce 5 Co 19 -type is found for the first time to exist as an equilibrium phase at a composition between La 2 Ni 7 and LaNi 5 . This phase is stable at high temperatures around 1000°C but decomposes into La 2 Ni 7 and LaNi 5 below 900°C. Numerous stacking faults are observed on basal planes in La 5 Ni 19 but the density of these basal stacking faults is greatly reduced in La 2 Ni 7 . Most stacking faults in La 5 Ni 19 are identified to be of the inter-block layer type while most of those in La 2 Ni 7 are identified to be of the intra-block-layer type.

A wavelength dispersive X-ray spectrometer is designed and developed for X-ray fluorescence analysis and spectroscopy using an X-ray microprobe at SPring‐8 BL39XU. The spectrometer uses a flat analyzer crystal, and X-rays from a small beam spot are dispersed by the crystal onto a position sensitive proportional counter. The energy resolution of the spectrometer is determined by the spatial resolution of the position sensitive proportional counter, and the additional use of the slit-scan can improve the energy resolution if necessary. Performance of the spectrometer is evaluated by using a conventional X-ray source, and preliminary experimental results of the X-ray microprobe by using brilliant hard X-rays from an X-ray undulator are reported. q 1999 Elsevier Science B.V. All rights reserved.

Tungsten (W) M III X-ray absorption spectra of a periodic multilayer, (Si/W) 100 /Si, were measured with the change of X-ray grazing angle using sample current method. Under not total reflection condition, the absorbance changed little except at W M III absorption edge. While under the total reflection condition, the absorbance increased with the increase of the X-ray energy and the increment changed from low to high at the W M III absorption edge. This result reflected the variation of the X-ray evanescent wavelength caused by the absorption effect of W.

Sulfur X-ray photoelectron spectra (XPS) and X-ray absorption spectra (XAS) of an aerosol sample collected by an Andersen sampler were measured using a synchrotron beam line. While the XPS was more surface sensitive than XAS, the detection limit of XAS was better than that of XPS. It was concluded that the XAS was more suitable for the chemical state analysis of sulfur in aerosol samples than XPS.

Kα 1,2 ( K - L 3,2 ) X-ray fluorescence spectra of MnF 2 have been measured for excitation X-ray energy at 688.0, 695.0 and 725.0 eV. Monochromatized synchrotron radiation was used for primary excitation. The fluorine K absorption spectrum of MnF 2 has also been measured and the absorption edge found to be at 690.0 eV. The excitation energy was thus 2 eV below, 5 eV above and 35 eV above the threshold. Multiply ionized Kα 3,4 ( KL - L 2 ) satellites, as well as the line broadening, were observed. The relation between the metal-F bond length and the F K absorption spectral shape is discussed.

TiB/Ti composite were produced by SHS (self propagating high temperature synthesis) under conditions of PHIP (pseudo-hot isostatic pressing). The synthesis conditions were optimized to produce highly dense materials conforming a high volume fraction of TiB. Self-propagating reaction of the Ti and B powders occurred above the α- to β-Ti transformation temperature (1155 K). The composites consist of Ti matrices with dispersed TiB reaction products of 2–30 μm size. Near fully dense composites with a TiB/Ti volume ratio of 33–44 vol.% were synthesized for B/Ti atomic ratios of 0.3–0.4 at pseudo isostatic pressures of 100 MPa. The Vickers hardness and fracture stress of the composites are 5.6–7.1 and 2.1–2.3 GPa, respectively, and the wear of the composite is approximately 7–9% of the Ti and Ti–6Al–4V.

We report magnetic vortex formation in epitaxially grown Co2Fe0.4Mn0.6Si (CFMS) Heusler alloy discs that was confirmed using photoemission electron microscopy and the magneto-optical Kerr effect. The phase diagram of magnetic domain structures as functions of the disc thickness (t) and diameter (D) indicates that the magnetic vortex is stable in wide ranges of t and D even for the epitaxial CFMS. The annihilation field of vortex core depended not only on the disc aspect ratio but also on t. Numerical simulation suggests that this t dependence results from extrinsic pinning of a vortex core due to the epitaxial growth.

The ${\ensuremath{\Theta}}^{+}$ pentaquark baryon was searched for via the ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{\ensuremath{-}}X$ reaction with a missing mass resolution of $1.4\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ (FWHM) at the Japan Proton Accelerator Research Complex (J-PARC). ${\ensuremath{\pi}}^{\ensuremath{-}}$ meson beams were incident on the liquid hydrogen target with a beam momentum of $1.92\text{ }\text{ }\mathrm{GeV}/c$. No peak structure corresponding to the ${\ensuremath{\Theta}}^{+}$ mass was observed. The upper limit of the production cross section averaged over the scattering angle of 2\ifmmode^\circ\else\textdegree\fi{} to 15\ifmmode^\circ\else\textdegree\fi{} in the laboratory frame is obtained to be $0.26\text{ }\text{ }\ensuremath{\mu}\mathrm{b}/\mathrm{sr}$ in the mass region of $1.51--1.55\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. The upper limit of the ${\ensuremath{\Theta}}^{+}$ decay width is obtained to be 0.72 and 3.1 MeV for ${J}_{\ensuremath{\Theta}}^{P}=1/{2}^{+}$ and ${J}_{\ensuremath{\Theta}}^{P}=1/{2}^{\ensuremath{-}}$, respectively, using the effective Lagrangian approach.

Glass-transition region is still a somewhat ``dark area'' in the field of materials science. In order to shed more light on this phenomenon, the glass-transition behavior was studied in a ${\text{Zr}}_{55}{\text{Cu}}_{30}{\text{Al}}_{10}{\text{Ni}}_{5}$ glassy alloy by monitoring its specific-heat capacity measured using a differential scanning calorimeter during heating in a step-scan mode. This reduces the influence of kinetic effects which shield the transition. It is suggested that two types of relaxation (likely related to the diffusivities of different alloying elements Cu and Ni on the one hand as well as Zr and Al on the other hand) take place and compete in the glass-transition region.

The phase transition behavior of the local structure around Fe in a shape-memory-alloy-related material, Ti(50)Ni(44)Fe(6), was evaluated by x-ray fluorescence holography. The Fe K alpha holograms were recorded at 225 and 100 K, which correspond to the parent and commensurate phases, respectively. The atomic images at both the phases show that the first neighbor Ti atoms around Fe, fluctuating in the parent phase, is strongly stabilized in the commensurate phase and that a clusterlike structure with a radius of 8 A degrees is formed in this lower temperature phase. These dynamically structural changes offer important keys to understanding the precursors to the martensite phase transition of the TiNi series.