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Most of the state-of-the-art thermoelectric materials are inorganic semiconductors. Owing to the directional covalent bonding, they usually show limited plasticity at room temperature1,2, for example, with a tensile strain of less than five per cent. Here we discover that single-crystalline Mg3Bi2 shows a room-temperature tensile strain of up to 100 per cent when the tension is applied along the (0001) plane (that is, the ab plane). Such a value is at least one order of magnitude higher than that of traditional thermoelectric materials and outperforms many metals that crystallize in a similar structure. Experimentally, slip bands and dislocations are identified in the deformed Mg3Bi2, indicating the gliding of dislocations as the microscopic mechanism of plastic deformation. Analysis of chemical bonding reveals multiple planes with low slipping barrier energy, suggesting the existence of several slip systems in Mg3Bi2. In addition, continuous dynamic bonding during the slipping process prevents the cleavage of the atomic plane, thus sustaining a large plastic deformation. Importantly, the tellurium-doped single-crystalline Mg3Bi2 shows a power factor of about 55 microwatts per centimetre per kelvin squared and a figure of merit of about 0.65 at room temperature along the ab plane, which outperforms the existing ductile thermoelectric materials3,4.The thermoelectric material Mg3Bi2 is shown to be ductile in single-crystal form along certain directions, with a room-temperature tensile strain of 100%, which is attributed to the gliding of dislocations. [ABSTRACT FROM AUTHOR]

With the widespread use of nuclear energy, the storage of surplus spent fuel has emerged as a critical issue that needs to be solved, especially for the efficient absorption of neutron radiation and secondary γ-rays generated by spent fuel produced when 10B absorbs neutrons. In this work, B4C/Al and W/B4C/Al coating were prepared on 316 L stainless steel by cold spraying. The microstructure and tensile properties of the coatings were investigated. The performance of the thermal neutron and secondary γ-rays absorption of the two coatings were simulated using the Monte Carlo approach. The results indicated that, compared to the B4C/Al coating, the W/B4C/Al coating exhibited better mechanical properties due to the tamping effect of the W particles. In addition, the secondary γ-rays absorption property was improved due to the addition of W. [ABSTRACT FROM AUTHOR]

Bias flow of molten metal in slab mold caused by unstable flow from submerged entry nozzle can deteriorate the slab quality during continuous casting. In this study, a novel electromagnetic swirling flow in nozzle (EMSFN) technique, which utilizes electromagnetic force to stabilize the flow in the nozzle and subsequently control the flow in the mold, is proposed. The mechanism for controlling unstable flow through EMSFN is explored through numerical simulation and water model experiments. In the results, it is shown that the molten steel is rotated under the effect of magnetic field and flows into the mold along the upper edge of the nozzle outlet, which weakens the impact of molten steel on the bottom of nozzle and stabilizes the outflow from nozzle. The flow field is consistently symmetrical on both sides of the nozzle. The impact depth of molten steel flowing down along the narrow sides of the mold on both sides is greatly reduced. The surface velocity on both sides of the nozzle changes uniformly. The range of surface velocity variation with EMSFN is only 10% of that with a conventional nozzle. The EMSFN technique can help prevent slag entrapment and improve the flotation of inclusions and bubbles. [ABSTRACT FROM AUTHOR]

Long-lived thermally activated delayed fluorescence (TADF) emission has gained extensive attention due to its potential application in information encryption, illumination, and bioimaging. However, developing visible light-excited TADF materials is still a significant challenge. Herein, visible light triggered TADF emission was achieved by embedding chlorine doped carbon dots (Cl-CDs) into a g-C3N4 nanosheet matrix through a simple microwave treatment. The strong electron-withdrawing effect of the chlorine dropping redshifts the excitation wavelength, and the covalent bonds between Cl-CDs and the matrix significantly stabilize the triplet state. Green TADF with a peak at 520 nm could be obtained in the Cl-CD composite when excited by the UV to visible light, and the afterglow signal can be observed by the naked eye for up to 5 s after a mobile phone flashlight irradiation. The composite also exhibited temperature-responsive color stability under UV light irradiation. Consequently, the Cl-CD composite was successfully employed in concepts of information encryption and single-component time delay WLED development. This research provides materials and strategies that may motivate the visible light-excited TADF applied in advanced information encryption and illumination areas. [ABSTRACT FROM AUTHOR]

Cold spray is a rapidly developing solid-state deposition technology in recent years. It has the characteristics of low spraying temperature and high velocity of spraying particles, hence showing a good prospect for preparing metal matrix composite (MMC) coatings and bulk materials. In particular, aluminum matrix composites have received great attention in electronics, aerospace and automobile industries due to their excellent physical and mechanical properties. In this paper, the research progress of cold-sprayed aluminum matrix composite coatings and materials was systematically introduced. Firstly, state of the art on cold sprayed coatings and materials with different reinforcing phases was presented. Then, research progress on different post-spray treatments, to improve the properties of as-sprayed deposit, was briefly discussed. Finally, the application fields and problems of cold-sprayed aluminum matrix composite coatings and materials were summarized. [ABSTRACT FROM AUTHOR]

Vortex slag entrapment during ladle teeming process causes liquid steel pollution, nozzle clogging, etc. Tangential velocity of molten steel is directly related to the vortex. Herein, the tangential velocity is reduced by the electromagnetic force generated by the interaction between a static electromagnetic field and the molten steel. Through the multiphysical field simulation, influences of the electromagnetic parameter, coil structure, coil position, and ladle structure on the vortex are investigated. Results demonstrate that magnetic induction intensity is proportional to the coil ampere‐turns, thereby affecting the vortex suppression. The action region of the static electromagnetic field expands when the coil diameter increases from 180 to 360 mm; it is beneficial to reduce the vortex critical height by 37.9%. The reduction of the distance between the coil and the molten steel also promotes the vortex suppression. The coil misalignment is beneficial to fully utilize the electromagnetic field; the critical height is reduced by 15%. The tangential velocity is changed when the nozzle diameter and eccentricity are optimized, and the vortex suppression will be amplified by using the electromagnetic field. This study provides the theoretical guidance for the optimizing design of the vortex suppression utilizing the static electromagnetic field. [ABSTRACT FROM AUTHOR]