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CsF-AlF3 based composite fluxes with different Ge contents which are in the form of GeO2 were developed by the method of solution synthesis, and their melting characteristics, phase structures and microstructures were observed and analyzed subsequently. Meanwhile, 2024 aluminum alloy was brazed successfully at 480℃ under the active effect of CsF-AlF3 flux with 4% (mass fraction, the same below) Ge doped. The results show that the liquidus temperature decreases from 477℃ to around 440℃and has the main phase composition of CsAlF4 and Cs2GeF6 when content of Ge exceeds 4%. And the new Cs2GeF6 changes the morphology of CsF-AlF3 flux to more regular polyhedron structure with fewer flocculent agglomerates. On the other hand, the flux with 4% Ge immensely promotes the spreading of Zn-15Al filler metal on the 2024 aluminum alloy at 480℃ and the shear strength of brazing lapping joints reaches 110MPa,with homogeneous structure of the joints,and with no obvious defects observed.

ZnCl2 and SnCl2 were added to the AlF3-CsF eutectic flux, which can be used for connecting aluminum alloy sheet by self-brazing at medium temperature. The influence of the amount of ZnCl2 and SnCl2 and the size of the T-joint area on the interface microstructure and the self-brazing joint mechanical properties was investigated. The interface microstructure, chemical compositions, defects and tensile fractography of the self-brazing joints were analyzed by metallographic microscope, scanning electron microscope and energy dispersive spectroscopy. The results show that the joints are soundly bonded when both the mass fractions of ZnCl2 and SnCl2 are about 4%; the replacement reactions between Zn2+, Sn2+ of flux and Al atoms of base metal occur during brazing, then the liquid metals of Sn and Zn appear, a great degree of Zn which has high solid solution with Al spreads rapidly to the base metal; Sn is distributed along the interface forming a low melting point metal layer with Zn and Al; the brazing of joints with small area can be realized easily; there are a lot of dimples on the fracture surface and the tensile strength of the brazing joint reaches (58±5)MPa.

Tension-shear test was carried out on middle temperature self-brazing aluminum honeycomb cores after high temperature aging by micro mechanical test system, and the microstructure and component of the joints were observed and analyzed using scanning electron microscopy and energy dispersive spectroscopy to study the relationship between brazing seam microstructure, component and high temperature aging properties. Results show that the tensile-shear strength of aluminum honeycomb core joints brazed by 1060 aluminum foil and aluminum composite brazing plate after high temperature aging(200℃/12h, 200℃/24h, 200℃/36h) is similar to that of as-welded joints, and the weak part of the joint is the base metal which is near the brazing joint. The observation and analysis of the aluminum honeycomb core microstructure and component show that the component of Zn, Sn at brazing seam is not much affected and no compound phase formed after high temperature aging; therefore, the main reason for good high temperature aging performance of self-brazing aluminum honeycomb core is that no obvious change of brazing seam microstructure and component occurs.

A holographic tensor metasurface (HTM) is proposed from the energy perspective to achieve flexible regulations of polarization and energy distributions for simultaneous transmissions of power and information. A dual‐polarization receiving metasurface with high isolation is also proposed to enable simultaneous receptions of power and information. Based on the two metasurfaces, a novel system for simultaneous wireless information and power transmissions (SWIPT) is established, which can transmit microwave powers and information signals by flexibly regulating the electromagnetic waves in different polarizations. The proposed HTM can generate non‐diffraction Bessel beams of two polarizations to keep high‐power transfer efficiency in an environment with obstacles. A rectifier circuit is designed with a wide dynamic range to integrate with the receiving metasurface to capture the strong powers and weak signals simultaneously. The effect of different modulations on the rectification efficiency of microwave‐to‐DC and the performance of the SWIPT system are analyzed. The SWIPT system is verified by experiments to realize simultaneous transmissions of information and powers by only using the metasurfaces, which is beneficial to integrate the wireless sensor networks, communication modules, and artificial intelligence algorithms to build up smart cities. [ABSTRACT FROM AUTHOR]