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IN718Plus superalloy with hierarchical microstructure has been successfully manufactured by laser directed energy deposition (LDED). Along building direction, microstructure varies from composing of epitaxial columnar grains oriented along <001> γ direction to equiaxed grains in flower like configuration. Striped Laves phase and fine γ'/γ'' precipitates form in the columnar grains, and would transform into fine Laves phase particles and nanoscale γ' precipitates at equiaxed layer. To improve the compositional homogeneity and microstructural stability, high temperature solution treatment has been explored on the superalloy. The treatment would not affect the morphology and orientation of columnar grains, but would redissolve Laves phase precipitates. Double aging treatment has also been performed to obtain homogeneous distributed γ' precipitates, and the synergistic regulation of microstructure enhances the mechanical property significantly, as causing the room temperature yield strength and tensile strength increased from 0.88 GPa and 1.14 – 1.04 GPa and 1.28 GPa, respectively. Moreover, the excellent mechanical property would be maintained upon 704 ℃, with yield strength of 0.93 GPa, tensile strength of 1.04 GPa and high elongation of 27.3%. [Display omitted] • IN718Plus superalloy with hierarchical microstructure has been successfully manufactured by LDED. • As-deposited microstructure is composed of columnar to equiaxed grains with hierarchical Laves phase and γ'/γ'' precipitates. • Appropriate heat treatment process has been explored as 1100 ℃/1.5 h + 788 ℃/8 h + 704 ℃/8 h to ameliorate the performance. • Excellent 704 ℃ tensile properties have been obtained with tensile strength of 1.04 GPa and elongation of 27.3%. [ABSTRACT FROM AUTHOR]

The α variant selection of integral as-deposited Ti-6Al-4V prepared by laser solid forming (LSF) has been investigated by Electron Backscattered Diffraction (EBSD). Six types of α variants exist all areas in the deposited cuboid although its microstructure varies from basket-weave to Widmanstätten (and undeveloped basket-weave) to ultrafine basket-weave along building direction. Clusters of three α variants always dominate in medium steady zone until the columnar to equiaxed transition (CET transition) occurs. α variant selection causes strong alteration of high angle grain boundaries (HAGBs), which might be correlated with self-accommodation of shape strains. Super variant selection in medium steady zone. Image 1 • The α variant selection of LSF Ti-6Al-4V has been investigated by EBSD. • Six types of α variants exist all areas in varying macro- and microstructures. • Clusters of three variants with 60° α/α GB always dominate in columnar grains. • The variant selection might be related with self-accommodation of shape strains. [ABSTRACT FROM AUTHOR]

• 3D carbon cloth frame decorated with Au particles was prepared by a simple one-step hydrothermal method. • CC with Au particles can be used to reduce the local current density and the nucleation overpotential during Li plating. • The Au-CC/Li electrode exhibits quite a promising stability during the repeated plating/stripping cycles. • The Au-CC/Li|LFP full cell delivers a high capacity retention. [Display omitted] Li metal has been proven to increase the energy density of rechargeable Li batteries significantly. However, the growth of Li dendrites has hindered the practical application of Li metal. Herein, an Au modified carbon cloth (Au-CC) was prepared by a simple one-step hydrothermal method. Benefiting from the miscibility of Li and Au on the surface of skeleton, the Au-CC can regulate the uniform plating/stripping process of Li effectively and alleviate the formation of Li dendrites, leading to a superior electrochemical performance (near 100% CE for 200 cycles at 2 mA cm−2). The as-fabricated Au-CC/Li electrode delivers a ultralong lifespan of 1200 h with low voltage hysteresis at 1 mA cm−2 for 1 mAh cm−2 in symmetric cells. By assembling the full-cell batteries using LiFePO 4 and Au-CC/Li as cathode and anode respectively, the capacity retention of 80.8% is achieved after 200 cycles at 3C. [ABSTRACT FROM AUTHOR]

Large-scale SiC nanowire arrays have been directly grown on the surface of carbon fibers via a molten-salt-assisted chemical vapor deposition process at relatively low temperature (1200 °C). The morphology, microstructure, and phase composition of the as-grown products were characterized by field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The characterization results indicate that the as-grown nanowires were of single-crystalline β-SiC phase with the growth direction along [111], lengths up to several tens of micrometers and diameters of 50–100 nm. The growth of the nanowires was governed by the molten-mediated vapor-liquid-solid (VLS) mechanism. The microwave absorption properties of the as-fabricated SiC nanowires/carbon fibers (SiC nw /C f ) composites were investigated over 2–12 GHz and a minimum reflection loss of −21.5 dB at 7.7 GHz could be achieved with 30 wt% SiC nw /C f as fillers in the silicone matrix. [ABSTRACT FROM AUTHOR]

Sr 0.9 La 0.1 TiO 3 thermoelectric ceramics with different contents of nano-sized Ag metal particles as additive were prepared by conventional solid state reaction method, and the influences of Ag adding content on the microstructure and thermoelectric properties were investigated. XRD characterization confirmed that the main phase was perovskite Sr 0.9 La 0.1 TiO 3 , along with a small amount of metal Ag phase. SEM images showed that all of the samples were dense, and the results of TEM indicated that the Ag particles accumulated at the grain boundaries to form a percolating network, contributing to increasing the electrical conductivity. Raman spectra of Sr 0.9 La 0.1 TiO 3 / x Ag samples before and after annealing in Ar+C atmosphere showed a great difference, resulting from the creation of oxygen vacancies and changes in the Ti O bond vibration and rotation mode. With increasing Ag adding content, the absolute value of Seebeck coefficient increased. Ag addition caused an increase in carrier concentration and acted as electrical connections between the grains, which improved the electrical conductivity and reduced the thermal conductivity to 1.4–3.4 W/m/K. Finally, the maximum ZT value of ZT 883K  = 0.30 was obtained for x  = 20  wt % samples. [ABSTRACT FROM AUTHOR]

A-site complex perovskite Ba 0.6 Sr 0.4 TiO 3 (BST) platelet microcrystals were successfully synthesized using a two-step Molten Salt Synthesis (MSS) method based on Bi 4 Ti 3 O 12 platelet precursor. During the synthesis process, the calcination temperature and the soaking time strongly influence on the morphology and particle size of BST. The optimal temperature for calcination is 740 °C. In addition, the increasing edge length with 5 μm–11.5 μm and thickness with less than 0.25 μm of BST platelets are obtained under the condition of rising soaking time from 5 h to 20 h, which can be used for preparing highly textured ceramics and microwave devices. Finally, the mechanism of topochemical microcrystal conversion reaction between BaCO 3 -SrCO 3 mixture and Bi 4 Ti 3 O 12 was discussed. [ABSTRACT FROM AUTHOR]