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Microstructures and mechanical properties of Ni matrix composites reinforced with amorphous SiO 2 particles by in-situ pyrolysis of polycarbosilane (PCS) coated on Ni powders were studied in this paper. The submicron spherical amorphous SiO 2 particles instead of traditional SiC uniformly distributing in the composites result from the generated silicon source by PCS pyrolysis combined with oxygen impurity in the preparation. The prepared composites achieve high yield strength, 172 MPa, and ultimate tensile strength, 494 MPa, as well as outstanding ductility, total elongation 28.4 %, which is improved 13.9 %, 50.6 % and 160.6 % compared with those for pure Ni samples, respectively. The effects of solid solution strengthening, grain refinement strengthening, reinforcement particle strengthening and dislocations behavior of at amorphous/crystalline interface on the combination of high strength and ductility of the composites were discussed. [Display omitted] • Amorphous SiO 2 reinforced Ni matrix composites were fabricated by in-situ pyrolysis of polycarbosilane coated on Ni powders. • Amorphous SiO 2 instead of crystalline SiC formed by the combination of silicon generated in the pyrolysis with oxygen. • The composites exhibit a combination of excellent tensile strength and ductility. [ABSTRACT FROM AUTHOR]

Abstract WB 2 /CrN multilayer films with thick modulation periods over 50 nm (Λ = 1400, 315, 235, 150, 55 nm) were synthesized by direct-current magnetron sputtering, and the influence of modulation period on microstructure and mechanical properties for the multilayer films was systematically studied. In WB 2 /CrN multilayer films, CrN sublayers present the columnar microstructure. As Λ decreases, the structure of WB 2 sublayers evolves from (110) orientation to (001) orientation to amorphous structure, and critical crystalline thickness for WB 2 sublayers is over 150 nm here. A transition layer, which shows the columnar crystal with size of 10–11 nm high and 2.5–3.5 nm wide caused by the effect of the crystalline interface of the CrN sublayers, is detected in WB 2 sublayers. Additionally, a-BN, WB 2 , WB 2 (N), CrN, Cr 2 N and Cr 2 O 3 phase are formed in the multilayer films. Moreover, film hardness mainly obeys the rule of mixture. The maximum hardness of 31.2 GPa is obtained at Λ = 315 nm due to crystalline WB 2 sublayers with (001) preferred orientation, and amorphous WB 2 sublayers greatly reduce the film hardness to only 22.3–24.3 GPa at Λ ≤ 235 nm. Consequently, the poor hardness leads to the higher wear rates (5.7–7.8 × 10−7 mm3/mN) of multilayer films with Λ ≤ 235 nm compared with those (2.9–3.3 × 10−7 mm3/mN) of other films. However, both the fracture toughness and adhesive strength of the films present an increasing trend with decreasing Λ, resulting from the soft CrN and BN phases and a certain amount of interface. In conclusion, decreasing the critical crystal-thickness of the WB 2 sublayers, controlling the N content in WB 2 sublayers and getting sharp interfaces will play important roles in developing the higher-performance WB 2 /CrN multilayer films. Highlights • WB 2 /CrN multilayer films with different bilayer periods over 50 nm are prepared. • A transition layer with nano-columnar crystal exists between WB 2 and CrN sublayers. • Critical crystalline thickness of WB 2 sublayers is over 150 nm in this work. • Decreasing bilayer period to ≤235 nm causes a reduction in hardness and wear rate. • Multilayer architecture promotes the film toughness and adhesive strength. [ABSTRACT FROM AUTHOR]

Abstract Nitrogen containing mesoporous carbon spheres act as a host for Se-S mixed cathode in Li-sulfur batteries. We prepare 50 and 60 wt% of active material (Se-S) containing carbon spheres using a single and two step infusion method individually. Loading of 60 wt% Se-S mixed active material in carbon spheres using a two step infusion method exhibits crystalline nature, whereas single step infusion method yields amorphous product. Interestingly, Se and S involve in the electrochemical reaction with Li. Among the products, 60 wt% Se-S loaded carbon spheres from a two step infusion method effectively suppresses the active material against shuttling and retains about 528 and 387 mAh/g of capacity at C/10 and 1C rate respectively due to the better electronic conductivity and polar nature of ∼5% nitrogen present in the carbon sphere. Further, Se-S@carbon sphere cathode demonstrates better electrochemical performance than S or Se@carbon sphere cathodes. The study deals with the effect of mixed active material loaded carbon spheres and the role of infusion method in improving the electrochemical behaviour of Li-S system both individually and in synergy. Graphical abstract Image 1 Highlights • Influence of infusion method in S-Se mixed cathode property in Li-S is studied. • Mesoporous carbon sphere with ∼5% N is exploited as Se-S cathode scaffold. • Both S and Se participate in the reversible electrochemical reaction with Li. • Better cycleability is observed with 60 wt% Se-S@C obtained from two step method. • Demonstrated 528 mAh/g up to 50 cycles and 273 mAh/g capacity at 2C rate. [ABSTRACT FROM AUTHOR]

Molybdenum substitution by chromium in ZrCr 1-x NiMo x alloys produces the segregation of Zr x Ni y phases, ZrCr 2 and ZrMo 2 Laves phases as it was stated in Part I of this paper. In order to study the contribution of these phases in ZrCr 1-x NiMo x alloys performance, secondary Zr 9 Ni 11 and Zr 7 Ni 10 , together with ZrCr 2 and ZrMo 2 Laves phases were synthesized and their crystalline structures determined with XRD patterns. Zr 7 Ni 10 exhibits an orthorhombic structure, whereas Zr 9 Ni 11 depicts a tetragonal structure. ZrCr 2 presents a hexagonal structure (C14), while ZrMo 2 depicts a cubic structure (C15). ZrCr 2 shows zero discharge capacities, while ZrMo 2 exhibits a first capacity value of 245 mAh g −1 . Zr 9 Ni 11 and Zr 7 Ni 10 phases exhibit maximum discharge capacities of 119 and 157 mAh g −1 , respectively. Theoretical results show that the hydride stability for ZrCr 2 is larger than that for ZrMo 2 . However, the great hydrogen storage capacity yields a slower desorption kinetics since it requires a considerable de-hydrogenation energy. The opposite effect is observed for the proposed hexagonal structure ZrMo 2 . The 100% charge of the alloys shows different results for the hydrogen evolution reaction. Zr 7 Ni 10 phase depicts a better performance since the required potentials are lower than −1.05 V. There is a change in the rate determining step ( rds) from a chemical recombination of surface hydrogen (Tafel pathway) in Zr 7 Ni 10 to a fast first electron transfer (Volmer step) for Zr 9 Ni 11 . Thus, the rds is strongly affected by the type of secondary phase dominant in each sample, being Zr 7 Ni 10 the most favorable. [ABSTRACT FROM AUTHOR]

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]

Abstract: The crystal structure of the new ternary compound TmCu4−x Sb2 (x =1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe4Ge2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a =7.00565(6)Å, b =7.83582(6)Å, c =4.25051(3)Å, Z =2. Investigated structure is an orthorhombically deformed derivative of the ZrFe4Si2 structure type. [Copyright &y& Elsevier]

• Tensile behaviors of triple-phase Ti/Ni nanolaminates are studied by MD method. • Acceptable plastic properties are obtained with proper amorphous layer spacing. • Co-deformation of different phases dominate plastic deformation. • ACIs and CCIs impede plastic deformation carriers penetrating through interfaces. • ACIs and CCIs connect plastic deformation carriers in different phases. [Display omitted] Superior properties of Ti/Ni nanolaminates prompt researchers to comprehend their mechanical behaviors deeply. Lacking investigations at several nanometers range limits their applications in high-precision fields, as the amorphous phase can be formed at the junction regions. By using the molecular dynamics method, three models are chosen to investigate the role of the amorphous layer and different interfaces in triple-phase Ti/Ni nanolaminates during the tensile process. The results demonstrate that mechanical performances of triple-phase nanolaminates are closely related to the fraction of crystalline and amorphous phases. Strength of the nanolaminates decreases with increasing amorphous layer spacing (d). However, acceptable plastic properties can be achieved when amorphous layer spacing satisfies d ≤ 3.91 nm. Microstructure evolution analysis reveals different plastic deformation carriers nucleate and propagate in crystalline and amorphous layers, which contains grain reorientation and basal dislocation propagation in Ti layer, partial dislocations propagation in Ni layer, formation and expansion of shear transformation zones in the amorphous layer. Plastic co-deformation of dissimilar phases dominates the plastic deformation of triple-phase nanolaminates. Crystalline/crystalline interfaces (CCIs) and amorphous/crystalline interfaces (ACIs) also play vital roles in plastic deformations. CCIs impede and absorb the grain boundaries moving toward the interfaces and then act as dislocation sources. ACIs accommodate local deformation at the interfacial regions, and are preferred sites for different plastic deformation carries nucleation. ACIs and CCIs can also connect the plastic deformation carries in different phases, which improves the overall plasticity of triple-phase nanolaminates. The insights obtained in this work can promote the design and application of advanced Ti/Ni nanolaminated materials. [ABSTRACT FROM AUTHOR]