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The effect of a high magnetic field on the microstructural evolution of a peritectic Al―18 at.% Ni alloy during directional solidification and its dependence on pulling speed were investigated. At a low pulling speed, the application of a 2 T magnetic field triggered the appearance of a primary Al3Ni2 phase. At higher pulling speeds, a high magnetic field application induced primary Al3Ni2 phase segregation that formed close to the central alloy regions. For all pulling speeds, the application of a high magnetic field induced bulk Al3Ni/Al eutectic formation on the upper and lower parts of the alloys, and promoted elongated growth of the peritectic Al3Ni phase along the magnetic field direction. Microstructural analysis indicated that microstructural evolution that was induced by high magnetic fields can be attributed to solute migration and melt flow that is regulated by magnetic, Lorentz, and thermoelectric magnetic forces and their coupling effects during peritectic solidification.

(Tb0.27 Dy0.73)1.04Fe1.95 alloys directionally solidified in a 4 T high magnetic field were heat treated in various high magnetic fields. Changes in magnetic domain structure, magnetostriction, and magnetization of the alloys were investigated. The alloys treated at 12 T showed the highest magnetostriction, followed in descending order by the alloys treated at 0, 6, 3, and 9 T. The alloys treated at 12 T showed the highest light and dark contrast in the domain image, followed in descending order by the alloys solidified at 6, 0, 3, and 9 T. The change in magnetostriction can be mainly attributed to the alteration of the light and dark contrast in the domain image induced by the high magnetic fields. It can be proved that the high magnetic field can be effectively applied to the directionally solidification and heat treatment processes of Tb–Dy–Fe alloys to improve their magnetostrictive performance.

Wetting transitions between molten metals and different solid substrates were investigated using the sessile drop method to evaluate the possibilities of regulating wettability by high magnetic fields (HMFs) during wetting. For most wetting counterparts, the molten-metal droplet outline showed an apparent change because of the influence of HMFs. Contact angles that were measured with HMFs decreased compared with contact angles that were measured without HMFs. The temperature and magnetic-flux density had an evident but more complicated effect on the wetting transition. For reactive wetting systems, the effect of HMFs on changes of element distributions at the metal/substrate interface may lead to a variety of wetting transitions. For non-reactive wetting systems, solidified metal droplets can move from the solid substrates after wetting. No detailed and comprehensive explanations on HMF wetting-transition mechanisms exist, and further work is required. This study contributes to perfect wetting mechanisms and theories and provides a scientific approach to control wettability.

We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures. The contact angles of both Al and Sn drops on the Al2O3 substrates decreased under high magnetic fields. These decreases strongly depend on the temperature, magnetic flux density, magnetic properties of the metal drops, and the reactivity of the metal drops with Al2O3. Our results reveal that the wetting behavior of molten metal drops on ceramics can be modified by a high magnetic field.

Chemical bonding has been regarded as an effective modification strategy to enhance the electrochemical performance of MXenes for Li-ion batteries (LIBs). However, the in-depth mechanism, especially concentrating on the regulation of chemical bond, is rarely explored. Herein, we design an atomically dispersed Fe in Ti3C2Tx MXene (Fe-Ti3C2Tx) by a doping route and the underlying mechanism of high-capacity LIBs is comprehensively investigated. Density functional theory (DFT) calculations reveal that unsaturated O coordination can be induced by electron transfer on Fe–O bond, which enables improved Li-ion adsorption on the surface of Fe-Ti3C2Tx nanosheet during charge/discharge process. The experimental observations from X-ray photoelectron spectroscopy (XPS) confirm the successful introduction of Fe atoms into intrinsic structure of Ti3C2Tx MXene, and the X-ray absorption spectroscopy (XAS) data verify the electron transfer of Fe–O bond. Moreover, Fe-Ti3C2Tx electrode exhibits greatly enhanced electrochemical performance (564.9 mAh g−1 at 50 mA g−1 under −10 °C), surpassing that of pristine Ti3C2Tx (77 mAh g−1). The cycling stability of Fe-Ti3C2Tx over 500 cycles (418.8 mAh g−1 at 200 mA g−1 under −10 °C). This work is expected to provide a guideline to develop brand-new MXene-based electrode materials with high-capacity for energy storage.

A specially developed experimental platform to measure the wettability of molten metals on solid substrates under high magnetic fields in combination with the sessile drop method is presented in this work. The desired magnetic field was generated by a superconducting magnet containing a channel with a diameter of 300 mm, in which the main body of the experimental apparatus was installed. The developed setup was used to observe the in situ wetting behavior of a molten metal on a solid substrate and simultaneously record sample images in real time under a high magnetic field during the wetting process. Contact angles were determined by analyzing the recorded images with the help of analytical software. Experiments using a typical molten metal and a solid substrate were conducted. The results revealed that the wettability of the molten metal on the solid substrate was obviously improved under a high external magnetic field.

The importance of the solid electrolyte interphase (SEI) layer for enhanced Li-ion storage has been well established, but primary understanding of the chemical components and structure of SEI layer on MXene-based electrodes remains incomplete. Here, we characterized the morphology and components of SEI layer on Ti3C2Tx and Ti3C2Tx/Fe2O3 electrode materials through combination of X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and transmission electron microscopy (TEM). The results show the SEI layer formed on pillar-structured Ti3C2Tx/Fe2O3 is dense and intact after long cycling, while the SEI layer on Ti3C2Tx electrode is noncontinuous. The pillar-structured Ti3C2Tx/Fe2O3 exhibits significantly enhanced capacity of 449.6 mAh g−1 at 300 mA g−1 after 100 cycles compared with Ti3C2Tx (140.2 mAh g−1) owing to the intact SEI layer with friendly chemical components. This work elaborates a recognition for SEI layer in MXene-based electrode, which provides a useful strategy for further SEI engineering.

The effect of a symmetrically distributed magnetic-field gradient on the microstructure and magnetic properties of solidified and semi-solid isothermally annealed Mn–89.7 wt%Sb alloy was investigated experimentally. In the absence of an applied magnetic field, primary MnSb phases had a dendritic morphology after solidification. The content of primary MnSb-phase dendrites in the lower part of the sample decreased slightly with depth. After semi-solid isothermal annealing treatment, primary MnSb phase particles in the MnSb/Sb eutectic matrix were relatively evenly distributed along the vertical axis of the sample. The application of a symmetrical high magnetic-field gradient caused primary MnSb-phase dendrites and alloy particles to distribute along the middle of the sample with a symmetrical gradient. The content of primary MnSb-phase dendrites and particles first increased and then decreased along the vertical axis of the sample. The saturation magnetization of this alloy is related to its MnSb phase content. Therefore, the saturation magnetization of the Mn–89.7 wt%Sb alloy samples that were solidified and semi-solidly isothermally annealed under a symmetrical magnetic-field gradient increased and then decreased along the vertical axis of the sample. This symmetrical distribution of the saturation magnetization intensity was caused by the magnetic force driving the Mn-enriched zone or MnSb particles towards the center of the specimen.

The effect of crystal orientation and grain alignment on the properties of magnetostrictive materials was investigated in TbFe2 alloys prepared via solidification under different high magnetic field conditions. The magnetostrictive property and magnetization behavior of the alloys were studied. The results revealed that the alloys that are oriented along the easy magnetization axis exhibit better magnetostrictive property in the low-field intensity region (than in the high-field intensity region). However, in the high-field intensity region, regular alignment of grains in the magnetization direction is essential for continued improvement in the magnetostrictive property of the alloys. If the magnetic phases of the TbFe2 alloy are oriented along the easy magnetization axis and the grains of the magnetic phases are aligned regularly along the direction of magnetization, the alloy will exhibit excellent magnetostriction property. This study may serve as a reference for the preparation of high performance rare-earth iron-based magnetostrictive materials.

In this work, Tb0.27Dy0.73Fe1.95 alloys were solidified in a high magnetic field of 4.4 T at various cooling rates. Changes in the magnetostriction, crystal orientation, magnetization, and magnetic domain of the solidified alloys were investigated. The application of the magnetic field can induce orientation of (Tb, Dy)Fe2 phase. However, the effect of the magnetic field is strongly dependent on the cooling rate. The alloy solidified at 5 °C/min shows the highest magnetostriction, strongest orientation, best contrast of light and dark in the domain image, and fastest magnetization, and followed in descending order by the alloys solidified at 1.5 °C/min and 60 °C/min. The change in the magnetostriction of the alloys can be attributed to the changes in crystal orientation and magnetic domain structure caused by both the magnetic field and cooling rate.

The PRMS_Storm model was built as a storm event, distributed hydrological model for studying the hydrological effects of forest composition and spatial distribution on storm-flow volume and peakflow rates in the Xiangshuixi Watershed in the Three Gorges Reservoir Area, in the Yangtze River Basin in southwestern China. We developed three simulation scenarios based on forest composition and their spatial arrangements across the watershed, including all mixed conifer-evergreen broadleaf forests (Scenario 1), all mixed evergreen broadleaf forests (Scenario 2), and mixed conifer + evergreen broadleaf + shrub forests (Scenario 3). We examined 11 storm events observed during 2002-2005. Compared with the existing forest covers, modeling results suggested that the amount of overland flow was reduced by 21, 23, and 22%, and the interflow increased by 16, 88, and 30%, for Scenarios 1, 2, and 3, respectively. During the same time, peakflow rates were reduced by 20.8, 9.6, and 18.9%, respectively. The reduction of peakflow rates was most significant when rainfall intensity exceeded 0.8 mm/min and events with a short duration and effect was minor when rainfall intensity was below 0.5 mm/min. In general, we found that Scenarios 1 and 3 were preferred for reducing storm-flow volume and peakflow rates due to their higher interception rates, large soil water holding capacity, and higher soil infiltration capacity. The modeled results suggested soil properties are important in affecting the flow processes and thus forest composition and forest spatial distributions will affect storm-flow volume and peakflow rates at the watershed scale. To maximize flood reduction functions of a watershed, high priority should be given to those forest types (Scenarios 1 and 3) in reforestation practices in the study region. This study suggests both forest composition and spatial pattern are important reforestation designs for flood reduction in the Three Gorges Reservoir Area.