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MgH 2 hydrolysis is an efficient and convenient method for hydrogen generation. By introducing rare earth hydrides, the hydrolysis properties of hydrogenated Mg 3 La hydrides (H Mg 3 La) and hydrogenated La 2 Mg 17 hydrides (HeLa 2 Mg 17 ) are enhanced compared with MgH 2 hydrolysis, but the energy efficiency of the three hydrolysis cycles is unknown and a relatively cheap MgH 2 -based hydride synthesis method still needs to be developed. We design and calculate for the first time the energy efficiency of such three hydrolysis cycles based on thermodynamics. Maximum energy efficiencies of 45.3%, 40.1% and 41.1% are obtained, which indicates that hydrogen generation from the three methods is feasible and energy favorable. A convenient method for La 2 Mg 17 hydrogenation is achieved by ball milling La 2 Mg 17 and Ni under 7 MPa hydrogen pressure at 25 °C. The ball–milled products, MgH 2 + LaH 3 + Ni hydrides composite, show excellent hydrolysis performance, and produce 1208 ml/g hydrogen in 40 min at 25 °C, with a reduced activation energy of 52.9 kJ/mol. These benefits result from the particle size refinement from ball milling and catalysis of LaH 3 and Ni. [ABSTRACT FROM AUTHOR]

The mechanism of microstructure evolution of 304 stainless steel (SS) during equal-channel angular pressing (ECAP) at 500 °C was investigated systematically by optical microscope (OM), transmission electron microscope (TEM) and X-ray diffraction (XRD). The results show that the refining mechanism of microstructure of 304 SS during ECAP behaviors as a hybrid model consisting of dislocation-subdivision mechanism and twin fragmentation mechanism, resulting in three kinds of nanostructure domains: (1) the equiaxial nano-grains with curving grain boundaries (GBs) having high angles of misorientation resulted from the cross-slip and movement of dislocations; (2) the equiaxial nano-grains with smooth and distinct boundaries resulted from the intersection between primary deforming twin bundles; (3) the secondary nano-twins formed in the primary deforming twins. The average nano-grain size ultimately obtained is in the range of 80 nm to 120 nm and the nano-twins have a width of 20–40 nm and a length of 100 to a few hundred nm. A low content about 10% (V/V) of deformation-induced martensite (DIM) is obtained in the first pass and remains almost constant during further passes of ECAP. The refining mechanism of DIM is also a hybrid model, including the refinement of banded DIM by the intersection with slipping bands and the newly induced fine martensite in submicron and nanometer grained austenite matrix. [ABSTRACT FROM AUTHOR]

The ZrO 2 - and Al 2 O 3 -based submerged entry nozzle (SEN) clogging during continuous casting of a RE-treating sulfur resistant casing steel is studied experimentally based on morphological analysis and the related thermodynamic calculations. The results show that the ceramic cloggings exists both in the inner-wall and outlet regions of SEN, while the latter is the main reason for terminating the casting with its clogging reaching 77% in the nozzle cross section area. The clogging is caused by RE-containing inclusions from molten steel and reoxidation products by the reaction between RE in molten steel and the initial formed cloggings on nozzle refractory. The possible existence state of RE in molten steel with its content has been discussed, and the clogging mechanism studied in detail. To prevent nozzle clogging, suggestions are given for continuous casting of the RE-treating steel with a modified RE treatment strategy for less solid inclusions and solute [RE] presented in liquid steel during refining process. Additionally, the optimization of nozzle geometry and its refractory materials may help as well. [ABSTRACT FROM AUTHOR]

Abstract: In this study, alkali hydroxides (NaOH, LiOH, KOH) were attempted as new-type catalytic additives to improve the hydrogen storage properties of MgH2 by ball milling. It is shown that the additives readily react with the MgH2 to form perovskite-structured NaMgH3 and KMgH3, but not the LiMgH3. Although the in-situ formed perovskite hydrides remain stable during hydriding/dehydriding cycles, both NaMgH3 and KMgH3 show predominant catalytic role on the hydriding and dehydriding of MgH2. In contrast, the LiOH modified MgH2 presents much inferior sorption kinetics because of the absence of LiMgH3. The catalytic mechanism of perovskite hydrides can be explained by the high hydrogen mobility in the perovskite structure. This study shows that such cheap hydroxides could be used as efficient catalysts to improve the hydrogen storage properties of high-capacity metal hydrides and complex hydrides. [Copyright &y& Elsevier]

Highlights: [•] The decomposition proceeded through several distinct steps. [•] The mixed materials show a dramatically low initial hydrogen release temperature. [•] The additives react with the Mg–B–H compounds rather than acting as catalysts. [•] The reaction process was studied using an in situ TEM. [Copyright &y& Elsevier]

Abstract: Magnesium borohydride [Mg(BH4)2] is an attractive complex hydride for hydrogen storage. In this study, attempts to synthesize Mg(BH4)2 were carried out by a solid–gas reaction through MgH2 and B2H6 in the absence of a liquid medium. The source of B2H6 was obtained by heating a mixture of NaBH4 and ZnCl2. The profile of pressure versus temperature indicated that the absorption kinetics of B2H6 by MgH2 were slow. Structural analysis confirmed the formation of Mg–B–H compounds. The reaction products presented two-step hydrogen release during heating. A small amount of hydrogen could be released from the as-synthesized Mg–B–H compounds at a low temperature of 215 °C. The slow reaction kinetics were significantly affected by the surface conditions of the MgH2 powders. [Copyright &y& Elsevier]

Abstract: Nanoscale MgH2 was synthesized through loading di-n-butylmagnesium (MgBu2) solution into the pores of ordered mesoporous silicas (SBA-15) with a pore diameter in a range of 5–10 nm, followed by freeze drying and hydrogenation treatment. The MgBu2 inside the pore channels of SBA-15 decomposed into MgH2 upon hydrogenation at 493 K under 6 MPa hydrogen. The nanoconfined MgH2 exhibited greatly decreased desorption temperature of 540 K, a reduction of 146 K in comparison with that of commercial MgH2, or 65 K reduction relative to that of MgH2 obtained from MgBu2 without confinement. Moreover, lower desorption temperature for the MgH2 supported by SBA-15 with smaller pore diameter. The improvement on the dehydrogenation properties of MgH2 was attributed to the nanosizing effect induced by the nanoconfinement of mesoporous silica. [Copyright &y& Elsevier]

Abstract: This study presents the first experimental evidence of a hydrogen-induced decomposition reaction in an Mg–6Zn–0.6Zr–0.5Cu alloy from combined transmission electron microscopy and atom-probe tomography characterization. The reaction takes place due to the presence of H in the Mg matrix, causes the decomposition of pre-existing, high-temperature Zr–Zn intermetallic rods into Zr-rich hydride and β′ (Zn3Mg2), and forms novel composite precipitates in the Zr-rich cores of the alloy during ageing at 180°C. The stoichiometry of the Zr–Zn rods was found to be Zn3(Zr1− x , Mg x )2, rather than Zn2Zr3, although both have a similar tetragonal crystal structure. The intrinsic link between the high-temperature Zr–Zn rods and the subsequent elongated composite precipitates, as depicted by the reaction, highlights the importance of engineering the Zr–Zn rod microstructures to control the final precipitate microstructure and effectively strengthen the Zr-rich cores, and hence the advanced Mg alloys. [Copyright &y& Elsevier]

A duplex chromizing process involving the salt bath chromizing of a plasma-nitrided tool steel was carried out at 773K for 3–24h. A single-phase CrN layer with a grain size ranging from 20 to 50nm and an underlying layer consisting of α-Fe and nanosized CrN grains with a grain size ranging from 40 to 80nm were formed by a 24h chromizing at 773K. The duplex chromizing mechanism was discussed. [Copyright &y& Elsevier]

Abstract: The electronic structures of cubic () and orthorhombic NaTaO3 (Pbnm and Pcmn) were investigated by density functional theory (DFT) method. It is shown that cubic NaTaO3 is an indirect bandgap semiconductor, whereas, orthorhombic NaTaO3 is a direct bandgap semiconductor at X point. The direct bandgap property is independent of space group for orthorhombic NaTaO3. Therefore, a steady direct optical transition can occur for this compound. The absorption spectra, calculated by DFT, fit very well with that of the experimental ones. The bandgap lowering and red shift of the absorption edge are found when the crystal structure changes from orthorhombic to cubic. [Copyright &y& Elsevier]

Abstract: In order to prevent tension delamination of concrete cover in midspan more efficiently, an attempt to strengthen reinforced concrete beams by combining unidirectional carbon fibre reinforced polymer (CFRP) sheet (to bond to the tension faces of the beams) and bi-directional glass fibre reinforced polymer (GFRP) sheet (to wrap 3 sides of the beams continuously) was proposed. The feasibility and potential advantages of the attempt were discussed. A comparative test program including ten beams was carried out. The test results showed that the hybrid CF/GF reinforced polymer (H-CF/GF-RP) strengthening could not only prevent the tension delamination of the bottom concrete cover, but also lead to a significant increase of deformation capacity of the strengthened beams at a very low cost compared to CFRP strengthening. [Copyright &y& Elsevier]

Steinernema populi n. sp. was recovered by baiting from beneath poplar trees in China. Morphological and molecular features provided evidence for placing the new species into the Kushidai clade. The new species is characterized by the following morphological features: third-stage infective juveniles (IJ) with a body length of 1095 (973–1172) μm, a distance from the anterior end to excretory pore of 77 (70–86) μm and a tail length of 64 (55–72) μm. The Body length/Tail length (c) ratio and Anterior end to Excretory pore/ Tail length × 100 (E%) of S. populi n. sp. are substantially greater than those of all other 'Feltiae–Kushidai–Monticolum' group members. The first-generation males can be recognized by a spicule length of 66 (57–77) μm and a gubernaculum length of 46 (38–60) μm. The new species is further characterized by sequences of the internal transcribed spacer and partial 28S regions of the ribosomal DNA. Phylogenetic analyses show that Steinernema akhursti and Steinernema kushidai are the closest relatives to S. populi n. sp. [ABSTRACT FROM AUTHOR]

The cations of sulfur clusters exhibit intensities of significance on the mass spectra of sulfur clusters generated in direct laser vaporization. We have acquired numerous isomers of cationic sulfur clusters by means of the B3LYP DFT method. According to total energies, the most stable Sn+ (n=3–13) isomers are predicted. Many cationic clusters are composed of two-fold atoms; those with one-fold and three-fold atoms are higher in total energy. The most stable isomer of some cationic clusters shows a structure completely different from that of the corresponding neutral cluster. [Copyright &y& Elsevier]

Hydrolysis of Zr(BH 4) 4 ·8NH 3 in deionized water can generate high purity hydrogen at room temperature. However, the sluggish hydrolysis kinetics of Zr(BH 4) 4 ·8NH 3 hinders its practical use. To improve its hydrogen generation properties, the effects of magnetic stirring, changing hydrolysis solution and tuning the ammonia coordination number on the hydrolysis properties of Zr(BH 4) 4 ·8NH 3 were investigated. Results show that both changing hydrolysis solution and tuning the ammonia coordination number can enhance the hydrolysis kinetics. The hydrolysis kinetics properties of Zr(BH 4) 4 ·8NH 3 were significantly improved in MgCl 2 and CoCl 2 solutions. The Zr(BH 4) 4 ·xNH 3 (x ≤ 8) samples were synthesized by a ball-milling method with different ammonization time (10, 60 and 180 min). Both the hydrolysis kinetics and hydrogen yield of Zr(BH 4) 4 ·xNH 3 (x ≤ 8) were enhanced as the ammonia coordination number (x) decreased. Thus, tuning ammonia coordination number is an effective way to control the hydrolysis properties of Zr(BH 4) 4 ·xNH 3 (x ≤ 8). • The effects of magnetic stirring, changing hydrolysis solution and tuning ammonia coordination number were investigated. • MgCl 2 and CoCl 2 solutions could improve hydrolysis kinetics of Zr(BH 4) 4 ·8NH 3. • Tuning ammonia coordination number(x) could effectively control hydrolysis properties of Zr(BH 4) 4 ·xNH 3. [ABSTRACT FROM AUTHOR]

Mg(In) solid solution, which was prepared by mechanical alloying, can be reversibly formed by dehydriding from its hydrogenated products (MgH2, MgIn and Mg2In). In situ X-ray diffraction analysis for the dehydriding process revealed that the Mg2In and ordered MgIn compounds transformed to the disordered MgIn compound (β phase), which then reacted with the MgH2 to form the Mg(In) solid solution, and vice versa. The Mg(In) solid solution shows decreased reaction enthalpy compared with pure Mg. [ABSTRACT FROM AUTHOR]

Chao Shao area is a littoral under the jurisdiction of Guangdong province, abutting on Fujian. Historically, the area was relatively isolated from other parts of China until 1990s, when it started to take a small number of immigrants from other regions. People residing in this area speak in unique dialect and have distinct lifestyle. Allele frequencies for the 15 short tandem repeats (STR) loci included in the AmpFLSTR® Identifiler™ kit were obtained from a sample of 144 unrelated Chinese born and living in the Chao Shan area, South China. [Copyright &y& Elsevier]

To improve the hydrogen storage properties of Y Zr Fe alloys, the alloying with Ti was carried out to obtain Y 0.7 Zr (0.3- x) Ti x Fe 2 (x = 0.03, 0.09, 0.1, 0.2) alloys by different processes. It was expected that Ti would substitute Zr and decrease the lattice constant of YFe 2 -based C15 Laves phase. All Y Zr Ti Fe quaternary alloys consist of the main Y(Zr)Fe 2 phase and the minor YFe 3 phase. Despite the large solubility of Ti in Zr or Zr in Y, the Ti incorporation into Y Zr Fe alloys results in the inhomogeneity of Y and the segregation of Ti, and thus decreases the hydrogen storage capacity. Only the alloy Y 0.7 Zr 0.27 Ti 0.03 Fe 2 containing very few Ti shows the substitution of Ti to Zr and the resultant improvement in the dehydriding equilibrium pressure. • Ti element was chosen to substitute the Zr in Y Zr Fe alloys. • The addition of much Ti results in the inhomogeneity of Y and the segregation of Ti. • Only a trace amount of Ti could substitute the Zr in Y(Zr)Fe 2 phase. • The alloy Y 0.7 Zr 0.27 Ti 0.03 Fe 2 shows the increase in the dehydriding equilibrium pressure. [ABSTRACT FROM AUTHOR]

Owing to fast kinetics, high equilibrium pressure and impressive volumetric hydrogen storage density at ambient temperature, ZrFe 2 based alloys are promising candidates to composite with high pressure compressed hydrogen tanks and thus reduce the working pressure and volume of high pressure tanks. However, simple ZrFe 2 alloy exhibits rather high de-/hydriding equilibrium pressure and large hysteresis, which are not coupled with the dis-/charging performances of high pressure tanks. In this work, to tune the plateau characteristics and hysteresis of ZrFe 2 alloys for potential application in high-pressure hybrid hydrogen storage tanks, the effects of Cr/V element substitution for Fe on the phase structure and hydrogen storage behaviors were systematically investigated in Zr 1.05 Fe 2- x Cr x (0.1 ≤ x ≤ 0.3) and Zr 1.05 Fe 1.85 Cr 0.15- x V x (x = 0.05, 0.075, 0.1). It has been found that the Cr and V substitution could effectively decrease the equilibrium pressure due to the enlarged unit cell of Laves phase, while the V substitution could greatly improve the hysteresis phenomenon. However, too high Cr addition (x = 0.3) led to structure transition from C15 to C14 for the Zr 1.05 Fe 2- x Cr x. The alloy Zr 1.05 Fe 1.85 Cr 0.075 V 0.075 shows the best overall hydrogen storage properties with the capacity of 1.54 wt%, and the absorption and desorption equilibrium pressure of 13.63 atm and 9.73 atm respectively at 243 K. The equilibrium pressure of Zr 1.05 Fe 1.85 Cr 0.075 V 0.075 at ambient temperature could meet the requirements of high-pressure hybrid hydrogen tanks. • Cr/V substitution decreased the equilibrium pressure of Zr–Fe based alloys. • V substitution greatly improved the hysteresis phenomenon. • Zr 1.05 Fe 1.85 Cr 0.075 V 0.075 has a capacity of 1.54 wt%. • The plateau pressure of the above alloy meets the requirement of hybrid tank. [ABSTRACT FROM AUTHOR]

Abstract Bipolar plate is an important component in proton exchange membrane fuel cell. The machining of micro-channel array is a key process for the fabrication of metallic bipolar plate. This paper proposed a novel approach named electrochemical direct-writing machining for generating micro-channel array on thin metallic plate at one time, showing a high machining efficiency. In this method, an insulated mask with a row of micro through-holes was integrated to a metallic nozzle, the electrolyte ejected from the nozzle reached to the workpiece through micro through-holes, and then the micro-channel array could be generated from dots to lines by controlling the movement of workpiece. In the machining process, the non-processing zones were covered by the insulated mask, which avoided the stray corrosion. By analyzing the results of simulation and experiment, it was found that due to the accumulation of electrolytic product in the ending point, the profile of this point was different from that of the starting point. The parameters with the voltage of 20 V and pulse duty cycle of 20% were useful for preparing micro channel with good profile and low dimensional difference. And compared with other pulse frequencies, the pulse frequency of 2 kHz could obtain a deeper micro channel. With other parameters unaltered, the dimension of micro channel was decreased with the increasing moving speed of workpiece. At last, with the optimized parameters (voltage = 20 V, pulse duty cycle = 20%, pulse frequency = 2 kHz, and moving speed = 20 μm·s−1), ten micro channels with the length of 60 mm were generated at one time on a metallic plate with the thickness of 0.5 mm. The width was 302 ± 3.53 μm (Mean ± SD) and the depth was 95.9 ± 1.34 μm, showing a satisfied dimensional consistency. [ABSTRACT FROM AUTHOR]

Abstract Electrophoresis-assisted micro-ultrasonic machining (EPAMUSM) is an effective method for solving the problem of using traditional micro-ultrasonic machining (MUSM) to fabricate micro-holes in materials that are hard and brittle, namely the low utilization ratio of abrasive particles. EPAMUSM uses an electric field to attract the abrasive particles to the processing area during processing, which is useful for improving both the utilization ratio of abrasive particles and the processing quality. Numerical simulations of the concentration distributions of abrasive particles in MUSM and EPAMUSM show that the abrasive concentration on the tool surface is much higher in EPAMUSM. The concentration increases rapidly from 1 mol/m3 to 4.68 mol/m3 after 10 s in EPAMUSM. Comparative experiments show that EPAMUSM has advantages over MUSM under the same processing conditions: the EPAMUSM edge chipping rate (0.03) is much less than the MUSM one (0.22) and the EPAMUSM material removal rate (1.916 × 10−4 mm3/min) is marginally better than the MUSM one (1.718 × 10−4 mm3/min). Single-factor experiments are used to study how varying certain parameters (namely DC voltage, ultrasonic power, and spindle speed) affects EPAMUSM manufacturing quality and efficiency. Finally, the processing parameters are optimized by means of response-surface experiments, and the optimum EPAMUSM processing parameters are determined (namely an applied voltage of 7.5 V, an ultrasonic power of 22.5 W, a spindle speed of 300 rpm, and a mass fraction of 10%). [ABSTRACT FROM AUTHOR]

Abstract A convenient, high-density and low-cost hydrogen supply technology is essential to hydrogen energy system by providing hydrogen to fuel cell component. Magnesium silicide (Mg 2 Si) can be a good hydrolysis candidate due to its low cost and ability of releasing hydrogen gas during hydrolysis process. However, previous studies have demonstrated that Mg 2 Si could easily produce large amount of silanes during hydrolysis reaction, which may cause serious problem of explosive danger when in contact with air. Here it is the first time that Mg 2 Si was used for generation of hydrogen by a simple and convenient one-step hydrolysis reaction. In this study, hydrolysis kinetics and mechanisms of Mg 2 Si in NH 4 Cl and NH 4 F solutions were investigated. The silanes could be almost completely turned into hydrogen by introduction of fluorine ion during the hydrolysis reaction of Mg 2 Si, leading to very low silanes content in the produced hydrogen. The kinetic studies indicated that when the concentration of the NH 4 F solution increased to 13.0%, the hydrogen generation rate and the reaction yield were improved significantly and reached the best performance, producing 466 mL g−1 H 2 in 10 min and 616 mL g−1 H 2 in 30 min at 25 °C. The activation energy was calculated to be 37.3 ± 0.8 kJ mol−1. Furthermore, the hydrogen yield and the hydrolysis rate of Mg 2 Si can be further improved by high-energy ball milling. After ball milling for 2 and 5 h, the hydrogen generation yield in 30 min increased to 698 and 771 mL g−1, respectively, and the activation energy was decreased to 23.9 ± 0.6 kJ mol−1 and 12.9 ± 0.1 kJ mol−1, respectively. The results revealed that NH 4 F can be a promising reagent for promoting the hydrolysis of Mg 2 Si for onsite hydrogen supply. Highlights • Mg 2 Si was used to generate hydrogen for the first time. • Mg 2 Si in 13.0% NH 4 F solution shows excellent hydrogen generation performance. • The hydrolysis kinetics and mechanism were discussed. • Hydrolysis kinetics of Mg 2 Si can be further improved by high-energy ball milling. [ABSTRACT FROM AUTHOR]

Abstract Zr(BH 4) 4 ·8NH 3 is considered to be a promising solid state hydrogen-storage material, due to its high hydrogen capacity and low dehydrogenation temperature. However, the possible applications of Zr(BH 4) 4 ·8NH 3 have been greatly hampered by the complicated and less applicable synthesis process, which must be operated at relatively low temperature (<20 °C). Herein, we reported a simple and facile "heating-(ball milling) BM vial" method via physical vapour deposition to tackle this issue. By this technique, Zr(BH 4) 4 ·8NH 3 was successfully synthesized. Furthermore, composite formation by adding 10 wt% NaBH 4 to the as-prepared Zr(BH 4) 4 ·8NH 3 was found to be able to lower down the dehydrogenation peak of Zr(BH 4) 4 ·8NH 3 from 130 to 75 °C and more excitingly, the possible emission of B 2 H 6 and NH 3 from dehydrogenation of only Zr(BH 4) 4 ·8NH 3 was completely suppressed after addition of NaBH 4. This research presents a new hydrogen-storage system based on Zr(BH 4) 4 ·8NH 3 +NaBH4 composite and it also implies a new development methodology of future hydrogen storage materials. Highlights • A facile Zr(BH 4) 4 ·8NH 3 synthetic method, "heating-ball milling vial" was reported. • Some other unstable metal borohydride ammoniates may be synthesized by this method. • NaBH 4 might play as a catalyst in the dehydrogenation of Zr(BH 4) 4 ·8NH 3. [ABSTRACT FROM AUTHOR]

Pulse electrochemical sawing micro-machining (PECSM) is a non-conventional process. Having features of no tool wear, no cutting force, and good surface quality, this process is suitable for machining micro-grooves on the inner wall of hole. The rotating dentate cathode (RDC) is beneficial for the distribution of electrolyte and electrolytic products removal, thus reducing the effects of concentration polarization on the electrochemical reaction. This study focuses on the PECSM of micro-inner annular groove on 304 stainless steel tube using a pH-neutral NaClO 3 electrolyte. To study the effects of RDC on the process, the bubble layer structure (BLS) adhered to the surface of RDC was photographed using a high-speed camera. Under the condition of immersion, the symmetric distribution of two kinds of BLS adhered to the RDC surface. The four selected parameters (radius of dentate cathode, rotational speed of RDC, initial gap, feed rate) with different levels were carried out to study the process of PECSM micro-inner annular grooves on 304 stainless steel tube. Experimental results indicate that PECSM has high potential for machining micro-inner annular groove on metallic tube. A micro-inner annular groove that is 340 μm in depth and 263 μm in width was fabricated on a 304 stainless steel tube. [ABSTRACT FROM AUTHOR]

Hierarchical MoO 2 /N-doped carbon heteronanowires (MoO 2 /N-C H-NWs) are synthesised by simple calcination using organic–inorganic hybrid nanowires as a precursor and self-template. In the heterostructure, MoO 2 nanoparticles are not only anchored on but also embedded in the one-dimensional N-doped carbon matrix. The synergistic effect promotes the pseudocapacitance, decreases the charge transfer resistance, and buffers the volume change on the reaction of MoO 2 /N-C H-NWs with Li + . Therefore it endows the composite with enhanced kinetics and stability for reversible Li + storage. At a current density of 2 A g −1 , the MoO 2 /N-C H-NWs deliver a reversible capacity of 700 mAh g −1 after 400 cycles, which still remains 570 mAh g −1 even after 1500 cycles. The high capability suggests that the MoO 2 /N-C H-NWs may be a promising candidate for use as anode material in high-performance lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Based on TiAl alloys bearing high levels of Nb, which are prospective high-temperature intermetallics, a new dual-phase alloy (Ti–40Al–10Fe (at%)) with precipitate growth direction close to the slipping plane normal of the matrix was developed. Transmission electron microscopy revealed that the annealed alloy was composed of equiaxed grains of τ 2 -TiAl 2 Fe and γ-TiAl phases. Aging treatment at 1000 °C produced polygon-shaped γ-TiAl precipitate from the τ 2 -TiAl 2 Fe matrix. The precipitation reaction of the face-centered cubic structure of τ 2 -TiAl 2 Fe into the ordered face-centered tetragonal structure of γ-TiAl phase was systematically investigated in terms of crystallographic features, including mutual orientation relationship, growth direction, habit plane, side facets, and interfacial dislocation structure. The observed growth direction <973> was close to the normal of the slip plane {111}, with a discrepancy angle of ∼20°. Thus, the observed two-phase microstructure might significantly improve strengthening. It could also be quantitatively controlled by selection of precipitate and matrix with phase structures and lattice parameters that meet a certain requirement. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new type of vacuo plasmon energy gain observation technique: a three-point method. • Enlarging the surface plasmon energy gain structure in SE spectra. • Clearly observed surface plasmon energy gain structure of Au and Ag. • Potential for developing a new physical image for surface plasmons in vacuum. A surface plasmon energy gain for emitted secondary electrons (SEs) was recently observed in SE spectroscopy measurements from a tailor-made nanostructured Au specimen as a satellite on the high energy side of the vacuum level. However, thus far, this plasmon energy gain phenomenon has been observed only for Au samples because surface plasmons in Au arise at 2.3 eV, which is relatively far from the strong background cascade peak of SEs. Here, we report a brand-new three-point probe method, for enlarging the surface plasmon energy gain structure in SE spectra. Using this scheme, three different SE energy spectra were measured from nanostructured samples of Au and Ag. By combining their spectra, the surface plasmon energy gain structure of Au and Ag can be clearly observed. The observed structures revealed that the plasmon energy gain process for SEs contributing to a potentially observable feature in a spectrum occurs only in vacuum above the sample surface and is naturally related only to surface plasmons. This unusual plasmon energy gain phenomenon observed by the three-point probe method suggests the potential for development of a new physical image directly in space based on surface plasmons in vacuum above the surface of a medium. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nb complete dissolved into NiTi matrix at 950°C for 15h is first detected. [•] Phase transformation temperature is enhanced due to Nb solution. [•] The mechanism is explained through changes of elastic constants and Mulliken population. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Ce2Ni7-type crystal structure of Sm2Co7 compound was confirmed. [•] β and γ phases were identified as Sm2Co7H2.9 and Sm2Co7H6.4, respectively. [•] The desorption enthalpy of either β or γ phase was obtained. [•] The hydrogenation process was a three-dimensional-interface-controlled reaction. [•] The Sm2Co7 compound showed excellent de/hydrogenation stability. [Copyright &y& Elsevier]

The present work demonstrates the reversible hydrogen storage properties of the ternary alloy Mg 18 In 1 Ni 3 , which is prepared by ball-milling Mg(In) solid solution with Ni powder. The two-step dehydriding mechanism of hydrogenated Mg 18 In 1 Ni 3 is revealed, namely the decomposition of MgH 2 is involved with different intermetallic compounds or Ni, which leads to the formation of Mg 2 Ni(In) solid solution or unknown ternary Mg–In–Ni alloy phase. As a result, the alloy Mg 18 In 1 Ni 3 shows improved thermodynamics in comparison with pure Mg. The Ni addition also results in the kinetic improvement, and the minimum desorption temperature is reduced down to 503 K, which is a great decrease comparing with that for Mg–In binary alloy. The composition and microstructure of Mg–In–Ni ternary alloy could be further optimized for better hydrogen storage properties. [ABSTRACT FROM AUTHOR]

The hydrogenation/dehydrogenation characteristics and hydrogen storage properties of nominal Mg 3 Ag and Mg 3 Y alloys prepared by induction melting were investigated. The as-melted Mg 3 Ag alloy was composed of Mg 54 Ag 17 phase, while Mg 3 Y consisted of Mg 24 Y 5 and Mg 2 Y phases. Mg 54 Ag 17 transformed into MgAg and MgH 2 during the first hydrogenation, and the phase transition of the following hy/dehydrogenation cycles was Mg 3 Ag + 2H 2 ↔ MgAg + 2MgH 2 . Both Mg 24 Y 5 and Mg 2 Y undertook disproportion reactions and decomposed into MgH 2 and YH 3 . Experimental and calculated results demonstrated that there was no necessary relation between the thermodynamic stabilities and the size interstices in these alloys. The dehydrogenation enthalpy change (Δ H ) and entropy change (Δ S ) of Mg 3 Ag were calculated and compared with that of pure Mg, which indicated that the increase of Δ S could counteract the stabilization effect of Δ H , which offered a method for tuning the thermodynamic properties of Mg-based alloys. [ABSTRACT FROM AUTHOR]

Abstract: Nickel has shown to be a good catalyst for improving the hydrolysis performances of hydrogenated Mg3RE (abbreviated as H-Mg3RE, RE = La, Ce, Pr, Nd) through investigating the hydrolysis kinetics and mechanisms of hydrogenated Mg3RENi0.1 (abbreviated as H-Mg3RENi0.1). A material with superior hydrolysis performance, namely H-Mg3CeNi0.1 has been identified, which can generate 276 mL g−1 min−1 hydrogen in the first 1.5 min and achieve a total yield of 1088 mL g−1. Ni served to modify the hydrolysis mechanisms of H-Mg3La, H-Mg3Pr, and H-Mg3Nd to improve their hydrolysis properties. Moreover, Ni has been found to promote the direct hydrolysis of CeH3 to CeO2 to liberate more hydrogen and to render the stable Nd2H5 reactive towards water. Therefore, the studied H-Mg3RE systems all show improved hydrolysis properties after the addition of Ni. [Copyright &y& Elsevier]

Highlights: [•] The microstructure evolution of T92 steel after creep were studied systematically. [•] The spheroidal-shaped of M23C6 is more stable than the rod one during creep. [•] The coarsening kinetics of Laves phase was notably affected by plastic deformation. [ABSTRACT FROM AUTHOR]

Highlights: [•] P-milling solves the kinetic and synthetic problems of Mg(In) simultaneously. [•] Mg(In) solid solution catalyzed with in situ formed MgF2 is prepared. [•] Mg(In) solid solution shows improved desorption kinetics (E a =127.7kJ/mol). [•] Dual tuning of the thermodynamic and kinetic properties of MgH2 is realized. [ABSTRACT FROM AUTHOR]