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Compression tests of W-1.5ZrO 2 alloy were carried out on a Gleeble-1500D thermal simulator at temperatures ranging from 1000 °C to 1400 °C and strain rates ranging from 0.01 to 1 s−1. The flow stresses, microstructure evolution and processing parameters optimization in different deformation conditions were investigated. The relationship between flow stress, strain rate and deformation temperature were also established based on the Arrhenius model. Furthermore, the law of activation energy and material constants with the variation of true strain was obtained in consideration of the strain influence. During hot deformation, the main restoration mechanism for W-1.5ZrO 2 alloy was dynamic recrystallization (DRX) and dynamic recovery (DRV). DRV plays a dominant role in the high-temperature deformation of the W-1.5ZrO 2 alloy. Partial DRX occurs in tungsten alloy when the temperature rises to 1400 °C, at the same time high temperature and low strain rate leads to the original grain growth. The obtained processing map of dynamic material modeling is used to analyze the deformation mechanism and the instability mechanism of the W-1.5ZrO 2 alloy. For the strain of 0.5–0.6, the optimal processing parameters for the W-1.5ZrO 2 alloy were in the temperature range of 1300 °C–1400 °C and strain rate range of 0.1–1 s−1. • Flow behavior and processing map of W-1.5ZrO 2 alloy were studied. • The developed model generally has good prediction accuracy. • Power dissipation efficiency map and instability map were established. • The optimal processing parameters for the W-1.5ZrO 2 alloy were determined. [ABSTRACT FROM AUTHOR]

Abstract A Cu-0.41Mg-0.06Ca (wt.%) alloy was designed and prepared by melting and casting in air atmosphere, followed by equal channel angular pressing (ECAP) process up to 12 passes via Bc route at room temperature. The microstructure and properties of the alloy were investigated by means of hardness test, tensile test, electrical conductivity measurement and electron microscopes observation. After 12 ECAP passes, the initial coarse grains were refined significantly and the average grain sizes decreased to 0.57 μm. The coarse Cu 5 Ca phase was also fragmented and had the sizes of about 1–3 μm. The Cu-Mg-Ca alloy after 12 ECAP passes showed excellent comprehensive properties, with a yield strength of 619 MPa, an electrical conductivity of 67.86 %IACS and a total elongation of 10.4%. Compared with the Cu-Mg alloy under the same condition, the yield strength of the designed alloy after 12 ECAP passes was improved by 30 MPa and the electrical conductivity increased by 0.63 %IACS accompanied by almost same total elongation. The good comprehensive properties were attributed to the ECAP process and the addition of Ca. The ECAP process provided much high yield strength increments which accounted for more than 80% of the yield strengths after 12 ECAP passes. In addition, the addition of Ca in the Cu-Mg alloy promoted the grain refinement, improved the work hardening ratio, and increased the electrical conductivity. Highlights • The ECAPed Cu-Mg-Ca alloy showed better properties compared with the Cu-Mg alloy. • The ECAP process provided the majority of yield strength increments. • The addition of Ca benefited the grain refinement and the electrical conductivity. [ABSTRACT FROM AUTHOR]

Abstract The tungsten alloys reinforced by ZrO 2 were prepared using azeotropic distillation method combined with powder metallurgy method, and then the sintered tungsten alloys were swaged to obtain compact bars. The microstructures of W- x ZrO 2 (x = 0, 0.25, 1.0 and 1.5 wt%) alloys were investigated by means of SEM, XRD and TEM. The results show that ZrO 2 exist as a stable cubic phase in tungsten alloys by adding Y 2 O 3. Fine ZrO 2 particles (500–800 nm) are dispersed in the tungsten matrix, and thus refine the grain size and improve the physical properties and strength of tungsten alloys. With the increase of the ZrO 2 content, the relative density, hardness and compressive strength of tungsten alloys were all increased. The swaged W–1.5 wt%ZrO 2 alloy shows the finest microstructure with an average grain size of 47.18 μm, reducing 34.76% compared with that of pure tungsten. And thus, the swaged W–1.5 wt%ZrO 2 alloy achieves the highest compressive strength (1941.3 MPa) and failure strain (23.1%) at the same time, increasing 23.27% and 22.37%, respectively, compared with that of pure tungsten. Highlights • W-ZrO 2 alloys were prepared by azeotropic distillation and powder metallurgy process. • c-ZrO 2 particles (500–800 nm) were obtained and evenly distributed in W matrix. • ZrO 2 refined tungsten grain and improved strength and plasticity simultaneously. • Compressive strength of W-1.5%ZrO 2 alloys increases 23.27% in comparison with pure W. • Failure strain of W-1.5%ZrO 2 alloys increases 22.37% in comparison with pure W. [ABSTRACT FROM AUTHOR]

We report our facile and efficient approach for synthesizing Co-Fe alloy based oxygen reduction reaction (ORR) catalysts, in which alloy nanoparticles are encapsulated in nitrogen-doped carbon nanostructures. The catalysts with high hierarchical porosities are fabricated at an appropriate temperature of 775 °C without a further acid leaching treatment after pyrolysis due to the use of ZnO nanoparticles as auto-removable templates. Co/Fe atomic ratio is found to greatly influence the ORR catalytic activity. The catalyst with Co/Fe = 1 exhibits the best catalytic performance by showing an ORR onset potential of 0.99 V and a half-wave potential of 0.87 V (vs. RHE) in 0.1 M KOH, as well as 0.98 V and 0.83 V (vs. RHE) in 0.5 M H 2 SO 4 , better than or approaching the performance presented by a commercial 28.6 wt% Pt/C catalyst. The Zn-air battery using the synthesized CoFe@N-C catalyst delivers a higher power density at ambient conditions by air-breathing than the one using the 28.6 wt% Pt/C catalyst. Relatively higher atomic concentrations of both Fe and Co as well as more graphitic nitrogen in the surface of CoFe@N-C detected by X-ray photoelectron spectroscopy (XPS) may account for its excellent ORR catalytic activities both in alkaline and acidic environments. • E onset = 0.98 V and E 1/2 = 0.83 V (vs. RHE) in 0.5 M H 2 SO 4. • Using ZnO as an auto-removal template. • a strong dependence of ORR activity on Co/Fe ratio in the catalysts. • the catalyst with Co/Fe= 1 offers the best ORR activity. • high surface metal concentrations account for the high ORR activity. [ABSTRACT FROM AUTHOR]

The contact wires in high-speed railway industry should have high strength, high electrical conductivity, and high industrial manufacturing feasibility. An economical Cu-0.29Mg-0.21Ca (wt.%) alloy has been designed and synthesized by non-vacuum melting and casting followed by thermal-mechanical treatments. Microstructure evolutions and mechanical properties of the studied alloy were investigated systematically. Microstructure observations showed that after cold deformation, the initial grain size was significantly refined into small grains full of sub-structures with an average size of 400 nm. After homogenized at 780 °C for 1 h, followed by cold rolling reduction of 80%, then annealed at 200 °C for 1 h, properties measurements revealed that the studied alloy had outstanding comprehensive performance with an ultimate tensile strength of 545 MPa, a yield strength of 526 MPa, an elongation of 3.60%, and an electrical conductivity of 71.79%IACS. The high electrical conductivity was due to the addition of Ca which purified the copper matrix through reacting with some impurity elements and caused little electron scattering. The high strength was attributed to the dispersion strengthening, solid solution strengthening, sub-structure strengthening, and dislocation strengthening, in which sub-structure strengthening is dominate. [ABSTRACT FROM AUTHOR]

The microstructure evolution and properties of a typical precipitation strengthened Cu-0.82Cr alloy during continuous extrusion were investigated by means of optical microscopy, transmission electron microscopy, hardness and conductivity measurement. The severe plastic deformation and precipitation behavior of the alloy during deformation were discussed in detail. The results showed that hardness increased firstly until reaching the maximum value of 148 HB in right-angle bending, and then decreased in the extending extrusion zone. Severe deformation and precipitation process occurred during continuous extrusion, and the nano-scale precipitates inhibited the recrystallization in some extent, both of which contributed to the properties of the extruded alloy. The extruded alloy had an average grain size of about 1.5 μm, and it reached a yield strength, ultra-strength, elongation and electrical conductivity of 292 MPa, 346 MPa, 34% and 77.5%IACS, respectively. [ABSTRACT FROM AUTHOR]

High strength Cu-Ni-Si alloys were potential elastic conductive materials due to their high strength and high electrical conductivity. To address the trade-off between strength and electrical conductivity, a combined aging process has been developed to enhance the properties of a Cu-6.0Ni-1.0Si-0.5Al−0.15Mg-0.1Cr alloy after an initial thermo-mechanical heat treatment. The microstructure evolutions of the studied alloys were investigated by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and physical properties were evaluated through hardness measurements, tensile test and conductivity test. The results demonstrated that a hardness value of 381 HV, an ultimate strength of 1155.8 MPa, an elongation of 3.5%, and an electrical conductivity of 25.2%IACS were achieved after an appropriate combined aging process. Cold rolling led to the formation of a dense dislocation wall as a result of dynamic interactions among the dislocations and precipitates. During the second stage of aging, nanoscale precipitates formed in the first stage slowly coarsened and effectively pinned dislocations motion. The combined aging process increased the hardness and strength, without sacrificed the electrical conductivity. This work provided an effective route for balancing the strength and electrical conductivity of copper alloys. [ABSTRACT FROM AUTHOR]

A Cu–0.3 wt.%Mg–0.05 wt.%Ce alloy was designed and prepared by melting and casting. After hot rolled, the ingot was cut into rod-shape samples for equal channel angular pressing (ECAP) with different passes at room temperature. The microstructure evolutions were investigated using transmission electron microscope (TEM) observation and electron backscatter diffraction (EBSD) analysis. The severe plastic deformation (SPD) caused by ECAP made the grains elongated significantly. With the increase of ECAP passes, the fraction of high-angle boundaries (HABs) ( θ ⩾ 15°) increased and the microstructure was refined. Tension testing results indicated that the tensile strength was remarkably improved from 273.4 MPa before ECAP to 587.5 MPa after 8 passes of ECAP, maintaining an appropriate elongation of 11.4% and good electrical conductivity of 73.1%IACS. After annealing treatment at 300 °C for 2 h, the ECAP samples still maintained excellent comprehensive properties: tensile strength was 558.2 MPa, electrical conductivity was 74.7%IACS, and elongation was 13.2%, which showed bright prospect in high-speed railway as a contact wire material. [ABSTRACT FROM AUTHOR]

• Thermally stable La-Ni-B composites were synthesized. • La-Ni-B composites consisted of amorphous La-B-O and Ni-B. • High and stable catalytic performance for dehydrogenation of MgH 2. • La-incorporation effectively inhibited crystallization and growth of Ni. In this work, we synthesized La-incorporated Ni-B amorphous composites and investigated their effects on enhancing dehydrogenation/hydrogenation properties of MgH 2. MgH 2 with 5 wt% 2La-3Ni-B demonstrated significantly improved dehydriding kinetics. About 6.0 wt% hydrogen could be released within 5 min at 300 °C. Moreover, no decrease in deydrogenation rate was observed within ten cycles. XRD, XPS, SEM and HRTEM examinations revealed that the La incorporation into Ni-B resulted in an amorphous La-B-O structure that could keep its disorder state up to 600 °C. The crystallization and growth of Ni dispersed in the La-B-O structure was significantly retarded. Also the alloying of Mg with Ni or La was not observed. As a result, the added La-Ni-B composites showed higher structural and catalytic stability than Ni-B during hydriding/dehydriding cycling of MgH 2 at high temperatures. [ABSTRACT FROM AUTHOR]

Abstract: High temperature deformability and microstructural evolution of Ti–47Al–2Cr–0.2Mo alloy were studied by using a Gleeble-1500 simulated machine at temperature from 1050°C to 1150°C with strain rate from 2.5s−1 to 7.5s−1 and engineering compressive strain from 20% to 50%. The results indicate that the largest engineering compressive strain of the alloy increases with decreasing strain rate and increasing deformation temperature. It has been shown that the strain rate affects the largest engineering compressive strain of the alloy effectively. High temperature deformation mechanism of Ti–47Al–2Cr–0.2Mo alloy mainly refers to the bending and fracturing of the lamellar structures and dynamic recrystallization (DRX). Electron back scattered diffraction (EBSD) and transmission electron microscopic (TEM) results reveal the DRX mostly occurring at grains boundary and interlamellar spacing at a strain rate of 7.5s−1 is much finer than that at a strain rate of 2.5s−1 at 1150°C. [ABSTRACT FROM AUTHOR]

Abstract: Mg and Mg-based alloys are not only promising hydrogen storage materials due to their high storage capacities, but also potential reducing agents in the synthesis of sodium borohydride NaBH4, an attractive hydrogen source with 10.6wt% hydrogen content. In this study, the MgH2 formation kinetics in pure Mg and Mg–23.5wt% Ni was studied and correlated with NaBH4 synthesis kinetics. It was found that the hydriding kinetics of Mg–23.5wt% Ni was significantly improved owing to the fine laminar Mg/Mg2Ni structure. Ballmilling and surface treatment made the eutectic alloy absorb 2.0wt% hydrogen at 353K. When these materials were applied for the NaBH4 synthesis, it was found that the eutectic Mg–Ni alloy enhanced the NaBH4 formation kinetics at high temperatures. However, NaBH4 was not produced at 353K although MgH2 could be formed. [Copyright &y& Elsevier]

Abstract: Hydrolysis of sodium borohydride NaBH4 is a promising method for on-board hydrogen supply for fuel cells. In this study, the hydrolysis reaction was studied by starting with solid NaBH4 rather than aqueous borohydride solutions, and adding less amount of water in an attempt to explore the maximum hydrogen generation capacity. It was found that hydrogen could be liberated at very high rates and over than 90% conversion rates were achieved when the mole ratio of water to sodium borohydride was not less than 4:1. The final hydrogen generation capacity was achieved as high as 6.7wt%. Materials such as CoCl2 or cobalt powder were found to be effective as the catalysts for the hydrolysis reaction at such reaction conditions. A large heat effect due to the exothermic reaction and a low melting point of NaBO2·4H2O led to the acceleration of hydrogen generation at the latter part of the hydrolysis process. It is thus promising to utilize these reaction conditions to achieve high hydrogen generation capacity by proper system design. [Copyright &y& Elsevier]

• The effects of deformation and annealing on the properties of tungsten alloy were investigated. • The strength and toughness of tungsten alloy can be improved by large rotary swaging ratio. • The doping of zirconia prolonged the recovery and recrystallization process of tungsten alloy. • W-1.5ZrO 2 alloy has the best properties after annealing at 1100–1200 °C for 1 h. W-1.5ZrO 2 alloy bars with two diameters, named as D9 and D5, were prepared by liquid phase method and rotary swaging method. The effects of swaging and annealing on the microstructure and mechanical properties of tungsten alloys were investigated. Under the same swaging ratio, the compressive strength of D5 tungsten alloy and D9 tungsten alloy is 23.27% and 22.37% higty her than that of pure W, respectively. After multi-pass swaging, the diameter of tungsten alloy decreased from 9 mm to 5 mm, and the hardness and compressive strength increased by 14.6% and 21.93%, respectively. After multi-pass rotary swaging, the diameter of tungsten alloy is reduced from 9 mm to 5 mm, and the hardness and compressive strength are increased by 14.6% and 21.93% respectively. The fracture mode has gradually changed from intergranular fracture to trans-granular fracture. Therefore, the strength of tungsten alloy can be improved by adding zirconia and proper swaging process. With the increase of annealing temperature or time, recrystallization and grain growth will be caused. The addition of ZrO 2 can delay the recrystallization of tungsten alloy during annealing, and inhibit grain growth. When the annealing temperature is lower than 1200 °C, the compressive strength of tungsten alloy remains unchanged, while the failure strain increases. After annealing at 1500 °C, the strength and failure strain of tungsten alloy decreased by 18.9% and 35.7% respectively. In order to obtain excellent strength and toughness, annealing at 1100–1200 °C for 1 h can be chosen for W-1.5ZrO 2 alloy. [ABSTRACT FROM AUTHOR]

Abstract: Borohydrides, a group of compounds with large hydrogen contents, can generate hydrogen readily by their hydrolysis reaction. In this study catalysts based on nickel and cobalt were developed to accelerate the hydrolysis reaction for hydrogen generation. Catalysts in four forms were tested for each metal: fine metal powder, metal salt, metal boride and Raney metal. It was found that the hydrolysis reaction was primary a zero-order reaction under the catalysis of these catalysts. Although cobalt showed higher catalytic activity than nickel in most cases, Raney Ni exhibited almost the same activity as the Raney Co. Among four chemical forms for nickel, Raney Ni demonstrated the best performance. Moreover, Raney catalysts made from alloys of nickel and cobalt showed even higher activity. The reaction on Raney metals was also characterized by a slowdown in hydrogen generation rate at low borohydride concentrations because of a mass transfer limitation. [Copyright &y& Elsevier]

A convenient method was developed to synthesize potassium borohydride by a mechano-chemical reaction of saline hydrides with dehydrated borates with a planetary ball mill. Among the tested saline hydrides, MgH2 was the most effective reactant for borohydride formation. In order to improve the borohydride yield, it was necessary to add an excessive amount of MgH2. When a 35% excess of MgH2 was added, potassium borohydride yield reached 100%. The borohydride formation was strongly dependent on the water content in reactants. When the water content in KBO2 samples was over 24.8 wt.% (equivalent to KBO2·1.5H2O), no borate was converted into borohydride by the mechano-chemical reaction. [Copyright &y& Elsevier]

In order to enhance the effect of fluorination treatment (F-treatment) on charge–discharge characteristics of AB2-type Laves phase alloys, three pulverization methods were applied for the F-treated alloys; e.g. hydriding–dehydriding, dry ball-milling and wet ball-milling. As a result, it was found that the F-treated alloy powder obtained by the wet ball-milling had smaller particle size and larger specific surface area than those obtained by the other two methods. The F-treated alloy electrode prepared from the alloy powder obtained by the wet ball-milling showed good initial activation, high-rate dischargeability and relatively high discharge capacity. These results indicate that the wet ball-milling is a very effective pulverization method in enhancing the effect of the F-treatment. [Copyright &y& Elsevier]

A Cu-0.41Mg-0.06Ca (wt.%) alloy was processed by equal channel angular pressing (ECAP) for up to 12 passes via Bc route at room temperature, and its homogeneity was evaluated from three aspects of hardness, microstructure and crystallographic texture. The hardness was measured in detail on the whole transverse planes, and the microstructure and the crystallographic texture in the central and bottom regions on the transverse planes were investigated by electron backscatter diffraction (EBSD) technique. After 1 ECAP pass, the hardness in the central region was 9.4% higher than that in the bottom region; the microstructure in the central region consisted of the elongated grains, while that in the bottom region was composed of the slightly distorted grains; the crystallographic texture in the central region followed the ideal orientations of the ECAP crystallographic texture, nevertheless the crystallographic texture in the bottom region obviously deviated from any ideal orientation of the ECAP crystallographic texture. Then, with the increase of ECAP passes, the hardness and microstructure differences between in the two regions gradually weakened, and the deviation of the crystallographic texture in the bottom region gradually decreased. After 8 ECAP passes, the both regions showed the same hardness, the similar ultrafine-grained microstructure and the similar crystallographic texture. The difference formation should be attributed to the non-uniform strain caused by the friction between the sample and the die wall, rather than caused by the corner gap. The difference weakening should be attributed to the strain hardening behavior of metals. The strength calculation showed that the Cu-Mg-Ca alloy after 8 ECAP passes had almost the same yield strengths where 593 MPa for the central region and 583 MPa for the bottom region, showing only 1.7% difference. • Cu-Mg-Ca alloy after 1 ECAP pass had serious inhomogeneity. • Cu-Mg-Ca alloy after 8 ECAP passes reappeared good homogeneity. • Inhomogeneity formation was due to the friction between sample and die wall. • Inhomogeneity weakening was due to the strain hardening behavior of metals. [ABSTRACT FROM AUTHOR]

Magnesium was added into Cu-Cr alloy to overcome the traditional limitations of high-cost and large-scale manufacturing of Cu-Cr alloys and to unveil the acting mechanism of Mg on the microstructure and properties of Cu-Cr alloy. Effect of magnesium on microstructure and properties of Cu-Cr alloy has been investigated by means of hardness test, electrical conductivity measurement, transmission electron microscopy, three-dimension atom probe tomography technique and X-ray diffraction analysis. The precipitation sequence of Cu-Cr-Mg alloy was similar with that of binary Cu-Cr alloy. Additional magnesium in Cu-Cr alloy accelerated the process of precipitates nucleation, restrained the growth of the precipitates by segregating along precipitates surface during aging. This enhanced the stability of the deformation microstructure and improved the mechanical properties of the alloy. Cu-Cr-Mg alloy showed a better comprehensive properties and softening resistance performance than Cu-Cr alloy at elevated temperature. After aged at 480 °C, Cu-Cr-Mg alloy had a tensile strength of 540 MPa and an electrical conductivity of 79.2 %IACS for the peak aging states, and it still maintained a tensile strength of 515 MPa and an electrical conductivity of 80.8 %IACS after 4 h aging. [ABSTRACT FROM AUTHOR]

Ternary layered double hydroxide (LDH) are potential electrode material choices for supercapacitors (SCs) due to their various oxidation states and high theoretical specific capacitance. In this paper, FeCoNi-LDH composite with cross-braided flowers of nanoneedles has been prepared by a single-step hydrothermal method. By highlighting the structural and morphological advantages, the obtained ternary LDH shows lower resistivity in comparison with the binary LDH. As electrode material, the ternary LDH exhibits excellent electrochemical properties, such as superb specific capacitance of 2163.3 F·g−1 at 0.5 A·g−1 and good cycle retention rate of 93.8% after 5000 cycles at 20 A·g−1. Meanwhile, the assembled asymmetric flexible solid-state supercapacitor device can provide 44.8 Wh·kg−1 energy density at 807.5 W·kg−1. Moreover, two devices in series can also light up miniature light bulbs of different hues and maintain them for a long period when they are connected in series. • FeCoNi LDH with unique structure is prepared by one step hydrothermal method. • The unique structure LDH has open-channel nanonetworks for fast charge transport. • FeCoNi-LDH shows excellent properties as electrode material of supercapacitor. [ABSTRACT FROM AUTHOR]

The grain boundary precipitation induced by grain crystallographic misorientations in an extruded Al–Mg–Si–Cu alloy was investigated by electron back-scattering patterns and high resolution transmission electron microscopy. The results showed that compared with the recrystallization cube {1 0 0}〈0 0 1〉 texture, the deformation brass {1 1 0}〈1 1 2〉 texture prevailed in the microstructure. The brass texture mainly contributed for the formation of low angle grain boundaries, where the pre-β ″ /β′ phases were formed during precipitation. The recrystallization cube texture predominately induced the formation of high angle grain boundaries, where the Q ′ /Q phases related to the corrosion were precipitated. And, high and low grain boundary was 23.5% and 76.5% proportion in the microstructure, respectively. Finally, it was believed that in order to improve the resistance to intergranular corrosion of alloy, the recrystallization cube {1 0 0}〈0 0 1〉 texture should be inhibited as far as possible. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we explored the possibility of NaBH4 synthesis when Mg reacted with hydrous sodium borates under hydrogen. It was found that Mg could react with the water in molten hydrous borates to form MgO and release hydrogen, which can be used for NaBH4 synthesis. Then remained Mg would react with formed anhydrous borate to form NaBH4. NaBO2 conversion rate was decreased with increase of the crystalline water content in the hydrous sodium borates. Based on experimental results, a mechanism of NaBH4 formation when Mg reacted with hydrous sodium borates was suggested. [Copyright &y& Elsevier]

Abstract: In this work, influences of Na2O in compounds lying within the Na2O–NaBO2 composition domain on NaBH4 recovery have been investigated. It is found that Na2O plays different roles in NaBH4 formation. Na2O is beneficial in terms of NaBH4 formation and reaction kinetics when Al is used for NaBH4 recovery, but harmful to NaBH4 formation when Mg is used for NaBH4 recovery from compounds lying within the Na2O–NaBO2 composition domain. High borate conversion rates can be obtained when Mg reacts with compounds lying within the Na2O–NaBO2 composition domain with less Na2O or Al reacts with the compounds containing more Na2O. NaBH4 formation temperature depends upon the used metals. [Copyright &y& Elsevier]

Abstract: Hot-rolling experiments with a reduction from 10% to 60% in single pass were conducted on AZ31B twin-roll cast sheets. Optical microscope (OM), electron backscattered diffraction (EBSD) tests and transmission electron microscope (TEM) were used to investigate twinning and DRV/DRX behaviors at different stage in the hot-rolling process. Two types of twinning occurred in the initial stage of hot-rolling process. DRV and discontinuous recrystallization dominated at moderate strain while continuous DRX took place homogeneously throughout original grains at the largest strains. [Copyright &y& Elsevier]

Abstract: The mixtures of LiBH4 with halides of Ce or La in a molar ratio of 3:1 were investigated to explore their hydrogen storage properties. The ball milling of LiBH4 with chloride of Ce or La yielded Ce(BH4)3 and La(BH4)3, while fluoride of Ce or La did not react with LiBH4 during extended ball milling at room temperature. The dehydrogenation temperatures of the ball-milled mixtures were reduced to 220–320°C, which were much lower than that of pure LiBH4. The diborane emission during hydrogen release was observed at a low level. The dehydrogenation temperature is found to be affected by the composition of rare earth halides, but less influenced by ball milling time. The endothermic dehydrogenation reactions produced lithium halides, hydrides and borides of the corresponding rare earth element. Moreover, the LiBH4 +1/3(Ce, La)(Cl, F)3 showed partial reversibility through the formation of an unknown borohydride, allowing for a potential hydrogen storage system. [ABSTRACT FROM AUTHOR]

Effects of a modified fluorination treatment (F-treatment), ball-milling in a fluoride solution, on structural and electrochemical characteristics of Zr0.9Ti0.1Mn0.6V0.2Co0.1Ni1.1 alloy were investigated. As a result, it was found that the modified F-treatment improved charge–discharge characteristics such as the initial activation property, discharge capacity and high-rate dischargeability of the alloy. It was also found that the modified F-treatment could effectively deposit Ni species on the alloy surface, compared with the conventional F-treatment. These results suggest that the combination of F-treatment and ball-milling is very effective in forming a Ni-rich surface layer with catalytic activity, leading to improved charge–discharge characteristics. [Copyright &y& Elsevier]

LaB 6 is a unique plasmonic material, for which the localized surface plasmon resonance (LSPR) absorption band intrinsically lies in the near infrared (NIR) region. In this work, we synthesized spherical LaB 6 nanoparticles with a tunable size within 50–200 nm. The optical properties of these LaB 6 nanospheres were found to be sensitive to the thickness of surface oxide layer that was formed during the synthesis, purification and dispersion processes. In order to enhance the stability of LaB 6 nanoparticles in aqueous environment, LaB 6 @SiO 2 with a core-shell structure was successfully prepared. Both LaB 6 and LaB 6 @SiO 2 demonstrated low cytotoxity in biomedical tests when their concentrations were limited to 0.2 mg mL−1. The in vitro photothermal therapy experiment showed that 4T1 cancer cells were eventually apoptotic after being exposed to a 980 nm laser for 5 min at a considerably low power density of 0.82 W cm−2 and a low dose of 0.1 mg mL−1 for LaB 6 @SiO 2. The results suggest that these LaB 6 nanospheres are viable photothermal agents for biomedical applications. • Spherical LaB 6 nanoparticles were chemically synthesized. • The NIR light absorption of LaB 6 was sensitive to the surface oxide layer. • Core-shell LaB 6 @SiO 2 was prepared for biomedical compatibility. • Low concentrations of LaB 6 and LaB 6 @SiO 2 were biosafe. • LaB 6 @SiO 2 was effective agent for photothermal therapy. [ABSTRACT FROM AUTHOR]

Abstract The microstructure, residual stress, and mechanical properties of a Cu-0.05wt%Al 2 O 3 dispersion strengthened alloy in different treatment states were investigated. The alloy was cold forged with a reduction of 60%, followed by either normal annealing or creep annealing at 600 °C for 6 h. Compared with the cold forged alloy, the micro-yield strength and the residual stress of the creep annealed alloy were reduced by 8.2% and 80.3%, respectively. The significant decrease in residual stress after creep annealing could result from the elimination of voids and defects and the reduction of dislocation density in the sub-grains during heat treatment. The high micro-yield strength of the creep annealed alloy can be attributed to the well dispersed nano Al 2 O 3 particles effectively pinning the sub-grain boundaries at the elevated temperature. [ABSTRACT FROM AUTHOR]

Abstract The W-1.5 wt%ZrO 2 alloys were prepared through azeotropic distillation method and then fabricated by four different processing techniques. The effect mechanisms of original solutions containing different acidity on the physical characteristics of the doped tungsten powders were analyzed. The doped tungsten powders with lower degree of particle agglomerates can be prepared under the condition of the original solution with the pH value of 2. Hot isostatic pressing process is beneficial to obtain higher microhardness and excellent wear resistance compared to conventional sintering, vertical sintering and hot swaging process. Meanwhile, the vertical sintering process can fabricate alloy with the compressive strength of 2090 MPa and the critical fracture strain of 0.35, approximately 24.4% and 45.8% higher than those of the swaged W-ZrO 2 alloy, and approximately 55.3% and 98.1% higher than those of the swaged pure W, respectively. After swaging, though the swaged alloy has the highest density, the compressive strength and critical failure strain both decrease due to the growth of grain after annealing. The strengthening mechanisms of W-1.5%ZrO 2 alloys prepared by different techniques were discussed. Highlights • Effects of solutions with different acidity on W-ZrO 2 powders were studied. • Hot isostatic pressing process can obtain high microhardness and wear resistance. • Compressive strength and strain reach to 2090 MPa and 0.35, respectively. • Compressive strength and strain are 55.3% and 98.1% higher than those of pure W. • Lots of dimples can be found in the fracture surface of the vertical sintered alloy. [ABSTRACT FROM AUTHOR]

Thermal-mechanical treatment is critical for the synthesis of Cu-Ni-Si alloys with high strength and conductivity. In this work, a high-temperature/short-time pre-aging treatment (600 °C, 10 min) was introduced to the thermomechanical processes of Cu-Ni-Si alloys, and the effects of pre-aging on the microstructure and properties of the alloy were investigated in detail. The results showed that Ni 2 Si particles precipitated from the matrix during pre-aging, promoting the formation of a nanoscale microstructure after cold rolling (cold rolled by 85% reduction). The pre-precipitated Ni 2 Si particles that formed during pre-aging consumed part of the dissolved Ni and Si solutes in the copper matrix, resulting in a higher initial conductivity before the final aging process. The grain refinement effect and high deformation-stored energy benefited the subsequent final aging by lowering the aging temperature and improving the alloys' high performance. This provided a guideline for the design and development of high-strength, high-conductivity copper alloys. The strengthening mechanism and corresponding microstructure evolution are also systematically investigated. The pre-existing Ni 2 Si particles strongly hinder the mobility of dislocations during cold rolling and retard the recovery of sub-structures at room temperature, leading the grain refinement in the nanoscale. • An energy saving pre-aging treatment is proposed to enhance the performance of Cu-3.0Ni-0.72Si alloys. • The pre-aged alloys achieve higher initial conductivity and nano-sized microstructure and obtain 255 HV and 44 %IACS. • The pre-aging treatment accelerates the precipitation process of the Ni 2 Si particles at a lower aging temperatures (350 ℃). [ABSTRACT FROM AUTHOR]

The compression deformation behavior of the Cu-15Ni-8Sn alloy prepared by powder metallurgy was investigated under a temperature range from 300 to 573 K and a strain rate range of 5 × 10 −5 ∼1 × 10 −2 s −1 . The results showed that in a certain range of strain rates and temperatures, the stress-strain curve exhibited obvious serrated flows which were induced by dynamic strain aging (DSA). The activation energy calculations indicated that the DSA was mainly attributed to the interaction of Sn solute atoms with dislocations. In the microstructure of the alloy pre-deformed in the region of DSA, Sn atoms were more likely to aggregated along the slip bands and therefore resulted in the dynamic precipitation of Sn-rich phase at lower temperature than that of natural aging alloy without pre-deformation. [ABSTRACT FROM AUTHOR]

Two N-containing hydrocarbon based polymers polyacrylonitrile (PAN) and polyaniline (PANI) were found to be able to destabilize LiBH 4 , a potential hydrogen storage material, resulting in larger hydrogen capacities of more than 10 wt% with peak dehydrogenation temperatures around 344 °C. The results suggest that a co-destabilization effect was achieved through the interaction of B H and C H bonds, which was further enhanced due to the presence of nitrogen atoms in polymers. After rehydrogenation of the dehydrogenated products, LiBH 4 was found to be regenerated to a large extent in both of the LiBH 4 +polymer composites. Detailed analysis including XRD, FTIR, DSC-TG-MS, HRTEM, Raman, XPS and solid-state 11 B MAS NMR was performed to elucidate the dehydrogenation and rehydrogenation mechanisms in these composites. The results provide considerable information about interaction mechanisms among B H, C H, N H and C N bonds and also shed lights on the enhancement of LiBH 4 dehydrogenation and reversibility. [ABSTRACT FROM AUTHOR]

A novel freestanding hierarchical nested-network porous copper (HNNPC) was fabricated by one-step free dealloying. The Al 75 Cu 25 (at.%) alloy precursor was prepared with both pure Al phase and the intermetallic Al 2 Cu phase. The microstructure of the alloy led to the hierarchical porous structure characterized by larger ligaments (pores) at micron scale (ca. 3–5 μm) and the smaller ligaments (pores) at nanoscale (ca. 50–60 nm) through dealloying. The morphology, crystal structure, elemental analysis, surface area, pore sizes distribution, electrochemical and sensing properties of HNNPC have been studied. The resulted HNNPC had bicontinuous hierarchical structure, which met the electrochemical or chemical applications’ requirements, namely, (1) the larger pores providing rapid transport pathways for fast switching and (2) smaller pores at nanoscale having the large surface area for functionalization. The CV and EIS of HNNPC presented an electro-catalytic activity to glucose, which was promising as a glucose sensor with excellent sensitivity. Furthermore, HNNPC itself could also be a host of other active materials. [ABSTRACT FROM AUTHOR]

The potential thermoelectric Cu 2 GeSe 3 is limited by the unfavorable exorbitant electrical conductivity and the subsequent high electrical thermal conductivity. In this regard, we highlight a compensatory compositing strategy to synergistically optimize its thermoelectric properties by adding GeSe second-phase. Experimental results demonstrated that the GeSe additive compensated the carrier concentration and mobility to some extent, which suppressed the exorbitant electrical conductivity and led to much reduced electrical thermal conductivity and the final low thermal conductivity in (GeSe) x (Cu 2 GeSe 3) 1–x composites. Meanwhile, due to the decreased carrier mobility, the GeSe additive could also increase the effective mass of the Cu 2 GeSe 3 matrix, which significantly enhanced the Seebeck coefficient and power factor. Finally, with the synergistically optimized electrical and thermal transport properties of Cu 2 GeSe 3 via GeSe addition, the final figure-of-merit ZT values of composites were significantly improved. The peak ZT of the average of three times trials of 0.49 was achieved at 723 K for (GeSe) 0.02 (Cu 2 GeSe 3) 0.98 composite, which was 188% higher than its pristine counterpart. • Compensatory compositing strategy is used to lessen the inherent high κ e of Cu 2 GeSe 3. • The κ tot of composites and ratio of κ e /κ tot remarkably decreased by GeSe composite. • ZT max of ~0.49 at 723 K was achieved for (GeSe) 0.02 (Cu 2 GeSe 3) 0.98 composite. • ZT of the composite increased 1.88 times more than that of the pristine Cu 2 GeSe 3. [ABSTRACT FROM AUTHOR]

The hot deformation behavior of the W-1.0 m-ZrO 2 alloy over a temperature range of 1300–1600 °C and a strain rate of 0.005–1 s−1 was investigated. The microstructure after deformation was characterized using the electron back scatter diffraction (EBSD) technique. The flow stress behavior of the tungsten alloy indicates that the main recovery mechanisms of the W-1.0 m-ZrO 2 alloy during deformation are dynamic recovery (DRV) and dynamic recrystallization (DRX), with DRV playing a dominant role. The hot processing map for a real strain of 0.68 reflects that the optimal processing region is 1500–1600 °C, 0.1−1~1 s−1. When the temperature reaches 1600 °C, the grain orientation spread (GOS) value and dislocation density of the samples show a pattern opposite to that of other temperatures as the strain rate decreases due to the growth of recrystallized grains. The orientation of the texture component of the hot deformation samples was mainly composed of< 111 > and< 100 > , and there was a shift in the texture component from< 111 > to< 100 > with a decrease in strain rate at different temperatures. • The hot deformation behavior of W-1.0 m-ZrO 2 alloy in the higher temperature was studied. • The optimum processing conditions for W-1.0 m-ZrO 2 alloy at a deformation of 0.68 are: 1500–1600 °C, 0.1–1 s−1. • At 1600 ℃, the GOS value and dislocation density showed the opposite trend with other temperatures. • The orientation of texture components of hot deformed samples is mainly composed of< 111 > and< 100 >. • With the decrease of strain rate, the texture components move from< 111 > to< 100 >. [ABSTRACT FROM AUTHOR]

A dual-phase reinforced Cu-0.75 wt% Al 2 O 3 -0.75 wt% TiB 2 composite ingot was prepared by liquid phase in- situ reaction casting method and then processed by hot rolling and cold rolling. The microstructure and property evolution of the composite during processing were investigated, and the strengthening mechanism was determined. Spherical Al 2 O 3 particles with a size of 50～500 nm and irregular polygonal TiB 2 particles with a size of 50 nm～1.5 µm were formed in the Cu matrix. When the cold rolling reduction exceeded 80%, the strengthening particles flowed with the plastic flow of the Cu matrix. The violent shear action between the particles and the Cu matrix made the particle agglomerations separate, which enhanced the uniform dispersion of strengthening particles. For the reduction of 90%, the tensile strength, yield strength, hardness, elongation and electrical conductivity were 477 MPa, 452 MPa, 158 HV, 5.7% and 80.0%IACS respectively. The strengthening mechanisms were dislocation strengthening, dispersion strengthening and subgrain strengthening in descending order. Liquid phase in-situ reaction casting combined with large-deformation rolling is a promising process for the preparation of dual-phase reinforced dispersion strengthened copper matrix composite. • A Cu-0.75 wt% Al 2 O 3 -0.75 wt% TiB 2 composite ingot is prepared by liquid phase in-situ reaction casting method. • The combination of hot working and high cold working can effectively improve the particle distribution of the composite. • The strengthening mechanisms are dislocation, dispersion and grain boundary strengthening in descending order. [ABSTRACT FROM AUTHOR]

In this study, we report a novel and facile synthesis approach of boron-rich transition metal borides such as LaB 6 and TiB 2 through reaction of lithium borohydride (LiBH 4 ) with corresponding metal hydroxide or oxide at temperatures below 600 °C. A fast endothermic reaction occurred at around 350 °C in the ball milled mixture of 6LiBH 4 + La(OH) 3 or 12LiBH 4 + La 2 O 3 , efficiently producing crystalline LaB 6 nanoparticles of a size smaller than 100 nm. In comparison, the reaction of LiBH 4 with TiO 2 proceeded within a wide temperature range from 120 °C to 500 °C, resulting in the formation of nanocrystalline TiB 2 of only a few nanometers. This synthesis method proved to be a facile and general route to fabricate nanosized transition metal borides. [ABSTRACT FROM AUTHOR]

In this paper, the influences of microwave heating with wood-charcoal as the reducing agent, on the reducing characterization of mill-scale were systematically investigated. The microstructures of the samples were characterized before and after microwave heating using SEM. The SEM analysis results indicated that the high-grade reduced iron powders were prepared using microwave heating. It was concluded that microwave heating technologies can be applied effectively and efficiently to the reduction process processes of iron ore concentrate. [ABSTRACT FROM AUTHOR]

Highlights: [•] TEM and HRTEM are used to elucidate an age hardening behaviour. [•] Transition Matrix was used to analysis the diffraction patterns of η′ phases. [•] η′ Phases had [2 23]η′, [10 0]η′, [ 23]η′ zone axis in the [110]Al direction. [•] A new diffraction patterns model under the [110]Al zone axis was established. [•] Moiré fringes technique was used to analysis the HRTEM images of η′ precipitates. [ABSTRACT FROM AUTHOR]

• TiNi particles are uniformly distributed in the Cu-TiNi composites. • The diffusion (CuNi)Ti layer formed. • There is a semi-coherent relationship between the Cu matrix and (CuNi)Ti phase. • The mechanical property of composites increases by increasing TiNi content. Cu-TiNi composites with TiNi volume percentages of 1%, 5%, 10% and 15% were prepared by vacuum hot pressing and hot extrusion. The microstructure, thermal and mechanical properties of the composites were analyzed. The results show that diffusion of elements occurred at the interface between the Cu matrix and the TiNi particles during the preparation process, leading to the formation of a (CuNi)Ti diffusion layer. The TiNi particles are uniformly distributed in the Cu-TiNi composites, with a well-bonded interface with the Cu matrix. Cu matrix has major <111> + minor <001> fiber textures after hot extrusion. There is a semi-coherent relationship between the Cu matrix and the (CuNi)Ti phase, with an orientation relationship of (111) Cu ∥(103) (CuNi)Ti and an angle of 18.7° between the two crystal planes. Both the Vickers hardness and the compressive yield strength of the Cu-TiNi composites increased with increasing the volume percentage of the TiNi particles, while the thermal expansion coefficient showed an opposite trend. The thermal expansion coefficient, Vickers hardness and compressive yield strength of the Cu-15% TiNi composite are 14.11 × 10−6 /K, 154.4 Hv and 460.0 MPa, respectively. [ABSTRACT FROM AUTHOR]

The microstructural evolutions and properties variations of a CuCrZrY alloy processed by equal channel angular pressing (ECAP) with different passes were studied systematically. After 4 passes of ECAP, the average grain size was decreased to 500 nm, and the grain size distribution became more uniform during the subsequent processing. After 8 passes ECAP-ed and aged at 400 °C for 7 h, the samples' tensile strength and electrical conductivity are 560 MPa and 86.4%IACS. The main strengthening mechanisms are precipitation strengthening, low-angle grain boundary strengthening, and high-angle grain boundary strengthening (about 82% in total). Finite element simulation was carried out through ABAQUS to obtain the equivalent strain distribution diagram of ECAP, resulting in that the strain force of the outer region was less than that of the inner one. The inconsistency of deformation leads to the inhomogeneity of microstructure. These findings will effectively guide researchers to develop high-strength high-electrical conductivity copper alloys. [Display omitted] • The properties and microstructural evolution of a CuCrZrY alloy after ECAP for different passes were studied systematically. • The main strengthening mechanisms are precipitation strengthening, low-angle grain boundary strengthening and precipitation strengthening. • The CuCrZrY alloy after ECAP showed excellent tensile strength and electrical conductivity. • The strain force of the outer region was less than that of the inner region, and the inconsistency of deformation leads to microstructure inhomogeneity. [ABSTRACT FROM AUTHOR]

• C70250 plate with columnar grains along casting direction were produced by HCCM continuous casting. • Solid-liquid interface location is a key factor to control precipitate content in columnar grains. • Columnar grain plate had better plasticity than equiaxed grain plate due to grain orientation. C70250 (Cu-2.6 wt%Ni-0.5 wt%Si) alloy plates with straight columnar grains, inclined columnar grains and equiaxed grains were produced by a heating-cooling combined mold (HCCM) horizontal continuous casting, respectively, and the influences of microstructure on the mechanical properties of the alloy were studied. The results showed that, when the casting speed was 30 mm/min, the straight columnar grains along the casting direction formed in the C70250 alloy plate and the precipitate content was relatively high, ～ 10%. When the casting speed was 50 mm/min and 80 mm/min, inclined columnar grains and equiaxed grains formed, respectively, with a low precipitate content of 6%. The high casting speed made the solid-liquid interface at the entrance of the cold mold and the solidified plate was cooled rapidly due to strong cooling effect, which suppressed formation of precipitated phase. The yield strength of the alloy plate with equiaxed grains were 219 MPa and the elongation to failure was 36%. For the plate with inclined columnar grains, its yield strength (76 MPa) were obviously lower than that of the other two plates and the elongation reached 45%. Compared with the equiaxed grain plate, the columnar grain plate had smaller grain orientation difference, better intergranular deformation compatibility and intergranular deformation uniformity, which was mainly responsible for its better plasticity. [ABSTRACT FROM AUTHOR]

Highlights: [•] Spray deposition process was used to produce Al alloys with excellent performance. [•] The deposited alloys exhibited a high strength of 690MPa and elongation up to 17.2%. [•] The η′ phase was coherent with α-Al and their orientation relationship was studied. [•] The interface misfits and the transition matrixes of two phases were calculated. [Copyright &y& Elsevier]

Highlights: [•] Peak-hardness and softening resistance are improved with Zr and (Ni, Si) additions. [•] Zr and (Ni, Si) additions promote a homogeneous distribution of solute elements in the cast Cu–Cr–Zr–Ni–Si alloy. [•] Stacking faults and twins easily and extensively occur in the alloy with the additions. [•] Precipitates are refined and the precipitate morphology is modified by the additions of Zr and (Ni, Si). [ABSTRACT FROM AUTHOR]

Highlights: [•] Large size as-deposited billets of 7055 Aluminum alloy was successfully fabricated by spray forming technology. [•] The microstructure observation showed that there were equiaxed grains with the size of about 50μm. [•] The detrimental dendrite microstructure was suppressed completely in our as-deposited 7055 alloys. [•] After extruding, the peak-aged 7055 alloys showed high tensile strength (667MPa) and enhanced elongation (10%). [•] The microscopic fracture morphology of as-extruded specimens was the transgranular dimple fracture. [ABSTRACT FROM AUTHOR]

• Creep annealing (CA) improves dimensional stability of ADSC alloy dramatically. • CA reduces residual stress while increases micro-yield strength in treated alloy. • Residual stress reduction is mainly due to the decrease of dislocation density. • Micro-yield strength increases with the reduction of pores in CA treated alloy. This study aims to enhance the dimensional stability of alumina dispersion strength copper alloy via creep annealing treatment. The microstructure, residual stress and micro-yield strength of alloys after different treatments were investigated. During creep annealing, the residual stress in the alloy was dramatically reduced due to the decrease of dislocation density. The nano-Al 2 O 3 particles in the alloy did not coarsen or agglomerate during the high temperature treatment and retarded the growth of subgrains effectively, which played important roles in high micro-yield strength of creep annealed alloy. The pores were effectively reduced by the creep deformation during creep annealing, resulting in a more uniform residual stress distribution and an increase in micro-yield strength. Compared with extruded alloy, the residual stress of alloy creep annealed at 950 °C for 12 h was reduced by 88%, while the micro-yield strength increased by 9.7%, leading to a significant enhancement in dimensional stability of the alloy. [ABSTRACT FROM AUTHOR]

• Cu-4%Ag alloy was prepared by short-process and highly efficient technology "continuously directional solidification and cold drawing". • Cu-4%Ag alloy could be cold drawn continuously by the strain of 11.28 without intermediate heat treatment. After the drawing, the Cu-4 wt%Ag alloy wire with a diameter of 40 µm had good comprehensive properties. • Deformation mechanism and strengthening mechanism of the Cu-4 wt% Ag alloy during the cold drawing was revealed. A Φ40 μm Cu-4 wt%Ag alloy wire with high strength and high electrical conductivity was prepared by continuously directional solidification and cold drawing. The evolution of microstructure and properties was investigated by means of optical microscope observation, electron microscopes observation, hardness test, tensile test, and electrical conductivity measurement. The continuous columnar-grain structure uniformly distributed along the solidification direction in the as-cast alloy. The drawing process was divided into three stages: general deformation stage, large deformation stage and extreme deformation stage. The main deformation mechanisms of the alloy in each stage are corresponding to the dislocation slip and twinning, the dynamic recovery, the evolution of layered interface, and partial dynamic recrystallization. After the deformation with the drawing strain of 11.28, the tensile strength, yield strength, and electrical conductivity of the alloys were 1048 MPa, 886 MPa, and 75.2%IACS, respectively. The main strengthening mechanism of the alloys was grain refinement strengthening according to the calculation results of the strengthening model. [ABSTRACT FROM AUTHOR]

Abstract: Morphology, orientation and diffraction patterns of δ-Ni2Si precipitates in a Cu–Ni–Si alloy are investigated by TEM and HREM. Many disk-shaped nanosized δ-Ni2Si precipitates are uniformly distributed in Cu–1.5wt%Ni–0.34wt%Si alloy in an over-aging condition. The δ-Ni2Si precipitates preserve an orthogonal structure with a =0.708±0.005nm, b =0.504±0.005nm, and c =0.364±0.005nm. The orientation relationships of six variants of δ-Ni2Si precipitates with Cu-matrix can be determined as (100)p||{001}Cu, [100]p||〈110〉Cu and [010]p||〈110〉Cu. Two typical diffraction pattern models under [001]Cu and [111]Cu zone axis are simulated according to diffraction effects of multiple variants, secondary diffraction and the size of particles, which coincide with the experimental results perfectly. [Copyright &y& Elsevier]

Abstract: In this work, the composites of LiBH4 and AlF3 were prepared and their hydrogen storage properties were investigated. The AlF3 addition to LiBH4 resulted in significant decreases in dehydrogenation temperature. All the xLiBH4 +AlF3 (x =1, 2, 3, 5) composites started to release hydrogen from about 100°C. The dehydrogenation of the composites was accomplished through several steps, depending on the molar ratio of LiBH4 to AlF3. A new phase Li3AlF6 was formed during the first dehydrogenation step, which further reacted with LiBH4. AlB2 was formed only at temperatures higher than 300°C. Li2B12H12 was detected as an intermediate. The dehydrogenation reactions have significantly reduced and thus favorable enthalpy changes. However, the reversibility of the composites needs to be improved. [Copyright &y& Elsevier]

Abstract: High-resolution electron microscopy was used to research the age-hardening behaviors in 6005A alloy and the microstructural characterizations of precipitates. It was found that β″, β′ and Q′ precipitates had 12 orientation variants, respectively, the smaller size and a high-density β′′ precipitates existed in alloy for a long time, which played a very important role in controlling an anti-overaged softening behavior in 6005A alloy. Further, by the crystallographic interface and morphology analysis, a main reason was that a 2-dimensions coherency strain-field not only had the high-density β′′ precipitates become the biggest obstacle of dislocations movement, but also made them transform into β′ and Q′ precipitates with more difficulty. Moreover, it was also found that β′ and Q′ precipitates had weaker relatively strain-fields, the larger size and a lower density, which were largely associated with the reduction in hardness that occurred upon overaging. Further, the strengthening of precipitates on alloys could be summarized as: β″>Q′>β′. Based on the structural information, the quantitative Moiré fringes analytical technique was also used to verify the lattice parameters and orientation of precipitates. [Copyright &y& Elsevier]

• NiO/ZnO heterostructured nanowires were prepared following a two-step route. • An interdigital Au electrode with an integrated RuO2 heater was employed for gas sensing characteristics evaluation. • The sensor showed good sensing performance to ethanol. • Much higher ethanol response was observed in N2 than that in the air. NiO/ZnO heterostructured nanowires were synthesized, and their gas sensing characteristics were evaluated employing Au interdigital electrodes integrated on a miniature ceramic heater. [Display omitted] In this study, we report on the synthesis of the NiO/ZnO heterostructured nanowires by a facile two-step liquid phase route and their gas sensing characteristics employing Au interdigitated electrodes integrated on a miniature ceramic heater. Microstructural characterizations indicate that flocculent NiO particles are uniformly assembled on the outer surfaces of the single-crystalline ZnO nanowires, with diameters around 50 nm and lengths ranging from 500 nm to several μm. The gas sensing investigation indicates that the sensors based on NiO/ZnO heterostructured nanowires exhibit high sensitivity towards ethanol, good reversibility, reproducibility, stability, robustness towards humidity, and fast response/recovery rates at the determined optimum operating temperature of 300 °C. Interestingly, the sensor shows higher ethanol response but longer recovery time in N 2 compared with those in air. An ethanol sensing mechanism is proposed to explain the experimental results. [ABSTRACT FROM AUTHOR]