查看更多>>摘要：Selective-laser-sintering (SLS) three-dimensional (3D) printing technology was used to fabricate highly porous biomass-based carbon electrodes, which were prepared using pine wood powder mixed with phenolic resin as the SLS printing material. The pinewood powder content in the mixture was varied from 30 to 50 wt% to find the correlation between pinewood content and electrical conductivity and mechanical properties. The 3D-printed precursors were carbonized in a tubular sintering furnace to finally obtain SLS biomass porous carbon electrodes. The physical properties, microstructure, pore distribution, and electrical conductivity of the printed porous carbon electrodes were investigated by scanning electron microscopy, X-ray diffraction, and electrical conductivity tests. The results indicate that highly customized carbon electrodes with high porosity can be fabricated using pine composites in combination with the SLS 3D printing process.
查看更多>>摘要：Microstructure refinement and mechanical properties enhancement were achieved by utilizing friction stir processing (FSP) as post-treatment to 6061 aluminum alloy fabricated by wire and arc additive manufacturing (WAAM). FSP led to a significant microstructure refinement and porosity reduction. The average grain size decreased from approximately 128 mu m to about 5 mu m. Because of the refined microstructure and the reduced porosity, the average microhardness, yield strength, and ultimate tensile strength increased by 31.5 %, 23.3 % and 6.0 %, respectively. The elongation difference between the horizontal and vertical direction was reduced from 4.5 % to 1.4 %. The properties anisotropy caused by delamination was weakened by the FSP. This work provides a valid option for the quality assurance of the WAAM process of aluminum alloys.
查看更多>>摘要：Identifying stable materials with facile kinetics for the oxygen evolution reaction is an important step in decreasing the cost associated with the production of hydrogen from water. In this study, a previously unex-plored alloy, alloy L605, was evaluated for its ability to catalyze the oxygen evolution reaction and results were compared to nickel 200 and pure cobalt. Alloy L605 required an overpotential of 420 mV to achieve a current density of 10 mA/cm2. The overpotential was found to be lower than that required for nickel 200 and cobalt. Also, the surface composition of the alloy was analyzed to obtain insight into the catalytic surface.
查看更多>>摘要：The hierarchical micro-nano porous structure in this study was prepared on the surface of Ti-3Zr-2Sn-3Mo-25Nb (TLM) titanium alloy by electrochemical dealloying process, in which the size of the micro-grooves was 2.42 0.83 mu m in length and 0.58 +/- 0.12 mu m in width, and the size of the nanopores was 14.6 +/- 0.57 nm. The hier-archical porous structure was detected to significantly reduce the surface roughness and enhance wettability, which is beneficial for the adhesion and spreading of cells. Notably, the hierarchical porous structure remarkably up-regulated osteogenic differentiation and inhibited adipogenic differentiation. The relevant mechanism can explained as micro-scale grooves induced cell morphology and then guided differentiation behavior. In addition, the hierarchical porous structure also increased the contact area between the bone and the implant, and induced more new bone formation.
查看更多>>摘要：Microencapsulated phase change materials with graphene nanoplates (GNPs) embedded polyurea shell and n-docosane (C-22) as core material were fabricated via Pickering emulsion polymerization. GNPs was used in combination with regenerated nanochitin as Pickering emulsifiers for enhanced stability due to mutual hydrophobic and electrostatic interactions. The microcapsules with 10 wt% GNPs (GNPs10/PU@C-22) exhibited melting enthalpy as high as 185.5 J/g and thermal conductivity as high as 0.65 W/m.K. GNPs10/PU@C-22 was also used to prepare composite films that showed great potential in thermal management of mobile phone devices.
查看更多>>摘要：A low-cost, high performance TiC reinforced titanium matrix composite was successfully fabricated using an in situ reaction casting method. The results showed that the morphology and distribution of TiC in the micro-structure were the more important factors affecting the properties of composites. And due to the second phase strengthening of the TiC and the Cr element solid solution strengthening for titanium matrix, it provides exceptionally high strength and toughness (1034.5 MPa ultimate tensile strength and 9.0 % elongation) for ti-tanium structural components and increases extremely high hardness (50.4HRC) for titanium wear-resistant components. This study provides additional options for the application of low-cost titanium components.
查看更多>>摘要：High entropy oxides (HEOs) are an emerging material and widely investigated due to their unique high entropy effect. Since the first report on rocksalt structure HEOs in 2015, a variety of HEOs have been synthesized suc-cessively. Previously, we found Mg28Co17Ni19Cu16Zn16O96 possessed higher single-phase formation ability and better thermal stability than Mg19.2Co19.2Ni19.2Cu19.2Zn19.2O96. However, there are relatively few studies devoted to the effect of elemental composition of Mg-Co-Ni-Cu-Zn on the phase structure of Mg-Co-Ni-Cu-Zn-metal-O. In this work, we designed, synthesized and compared the phase structure combined with optoelec-trical properties of Mg19.2Co19.2Ni19.2Cu19.2Zn19.2Ti96O288 and Mg28Co17Ni19Cu16Zn16Ti96O288. Results indicate that the composition of Mg28Co17Ni19Cu16Zn16O96 which is more stable than Mg19.2Co19.2Ni19.2Cu19.2Zn19.2O96 in rocksalt structure HEOs can make Mg28Co17Ni19Cu16Zn16Ti96O288 more stable than Mg19.2Co19.2Ni19.2-Cu19.2Zn19.2Ti96O288 in ilmenite structure HEOs. Notably, the attenuation of sluggish diffusion effect of Mg28Co17Ni19Cu16Zn16Ti96O288 may effectively improve the electrical conductivity by composition and phase stability optimization.
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