Fluidity Of Liquid Metal Research Articles

3D Network of Liquid Metal-Embedded Graphene via Surface Coating for Flexible Thermal Management.

The rapid growth of flexible electronics has led to significant demand for relevant accessories, particularly highly efficient flexible heat dissipators. The fluidity of liquid metal (LM) makes it a candidate for realizing flexible thermal interface materials (TIMs). However, it is still challenging to combine LM with a conductive thermal network to achieve the synchronous improvement of thermal conductivity and flexibility. In this work, highly conductive flexible LM@GN/ANF films are made by coating LM nano-droplets with graphene nanosheets (GN) via sonication, and then they are combined with aramid nanofibers (ANF). The LM@GN/ANF film is found to have a thermal conductivity of 5.67Wm-1K-1 and a 24.5% reduction in Young's modulus, making it suitable for various flexible electronic applications such as wearable devices and biosensors.

Wide-Passband Reconfigurable Frequency Selective Rasorber Design Based on Fluidity of EGaIn

In this letter, we propose a wide-passband reconfigurable frequency selective rasorber (FSR) design based on the fluidity of liquid metal. To achieve wide-passband reconfigurability, a new type of reconfigurable frequency selective surface with wide-passband elliptic filter response is introduced for the first time, whose bandpass state can be switched to a perfect reflection state by controlling the injection and the extraction of liquid metal in microchannels. Furthermore, a new resistive film loop with a minimum insertion loss of 0.23 dB is presented by loading four circular spiral resonators. Finally, the FSR can realize the reconstruction of the absorption-transmission-absorption (ATA) and absorption-reflection-absorption (ARA) modes. The simulation results show that in ATA mode, the design exhibits a wide passband with a fractional 3 dB bandwidth reaching up to 42.8%, and a passband minimum insertion loss of 0.86 dB at 13 GHz. In ARA mode, the bandwidth for return loss less than 3 dB is 12.8%. Prototypes were fabricated and measured. Compared with previous FSRs, our proposed FSR has advantages such as reconfigurable characteristics, a wide transmission band, and high-frequency selectivity.

Determination of flow distance of the fluid metal due to fluidity in ductile iron casting by artificial neural networks approach

Abstract Ductile irons (DIs) have properties such as high strength, ductility, and toughness, as well as a low degree of melting, good fluidity, and good machining. Having these characteristics make them the most preferred among cast irons. The combination of excellent properties, especially in DI castings with a thin section, make it an alternative for steel casting and forging. But in the manufacture of thin-section parts, fluidity characteristics need to be improved and the liquid metal must fill the mold completely. The fluidity of liquid metal is influenced by many factors depending on the casting processes such as material and mold properties, casting temperature, inoculation, globalization, and grain refinement. In this study, an artificial neural network (ANN) model has been developed that allows for determining the flow distance of the liquid metal in the sand mold casting method under changing casting conditions of DI. Thus, the flow distance was estimated depending on the cross-sectional thickness during the sand casting under changing casting conditions. The experimental parameters were determined as casting temperature, liquid metal metallurgy quality, cross-sectional thickness, and filling time. Filling modeling was performed with FlowCast software. When the results were examined, it was seen that the developed ANN model has high success in predicting the flow distances of the liquid metal under different casting conditions. The calculated coefficient of determination (R 2) value of 0.986 confirms the high prediction performance of the model.

High thermal conductivity liquid metal pad for heat dissipation in electronic devices

Novel thermal interface materials using Ag-doped Ga-based liquid metal were proposed for heat dissipation of electronic packaging and precision equipment. On one hand, the viscosity and fluidity of liquid metal was controlled to prevent leakage; on the other hand, the thermal conductivity of the Ga-based liquid metal was increased up to 46 W/mK by incorporating Ag nanoparticles. A series of experiments were performed to evaluate the heat dissipation performance on a CPU of smart-phone. The results demonstrated that the Ag-doped Ga-based liquid metal pad can effectively decrease the CPU temperature and change the heat flow path inside the smart-phone. To understand the heat flow path from CPU to screen through the interface material, heat dissipation mechanism was simulated and discussed.

Gallium-Based Liquid Metal Amalgams: Transitional-State Metallic Mixtures (TransM2ixes) with Enhanced and Tunable Electrical, Thermal, and Mechanical Properties.

Metals are excellent choices for electrical- and thermal-current conducting. However, either the stiffness of solid metals or the fluidity of liquid metals could be troublesome when flexibility and formability are both desired. To address this problem, a reliable two-stage route to improve the functionalities of gallium-based liquid metals is proposed. A series of stable semiliquid/semisolid gallium-based liquid metal amalgams with well-controlled particle packing ratios, which we call TransM2ixes, are prepared and characterized. Through effectively packing the liquid metal with copper particles (which are found to turn into intermetallic compound, CuGa2, after dispersing), remarkable enhancements in electrical conductivity (6 × 106 S m-1, ∼80% increase) and thermal conductivity (50 W m-1 K-1, ∼100% increase) are obtained, making the TransM2ixes stand out from current conductive soft materials. The TransM2ixes also exhibit appealing semiliquid/semisolid mechanical behaviors such as excellent adhesion, tunable formability, and self-healing ability. As a class of highly conductive yet editable metallic mixtures, the TransM2ixes demonstrate potential applications in fields like printed and/or flexible electronics and thermal interface materials, as well as other circumstances where the flexibility and conductivity of interfaces and connections are crucial.

Influence of alloy elements and pouring temperature on the fluidity of cast magnesium alloy

The fluidity is one of the most important properties for cast alloy. The quality of castings is influenced by the fluidity of liquid metal, especially under gravity casting conditions. In this paper, the factors affecting the fluidity of cast magnesium alloy have been studied by vacuum suction method. The experimental data show that the relationship between the fluidity of magnesium alloy and pouring temperature can be described as an exponential damping curve. The length of freezing range, which varies with the content of alloy elements, such as Al, Zn, Mn and Ce, influences the fluidity of magnesium alloy. In Mg–Al–Zn–Mn–Ce alloy system inter-metallic phases precipitated during pouring reduce the fluidity of magnesium alloy.

Viscosity of liquid metals: An interpretation

The fluidity of liquid metals, like that of simple nonmetallic liquids, is a linear function of the ratio of unoccupied volume to intrinsic volume over long ranges as expressed by the equation varphi = B[(V/V(0)) - 1]. Values of V(0) obtained by extrapolating to varphi = 0 agree well with molal volumes of compact crystals at 20 degrees C calculated from densities.Values of the ratio varphi/[(V/V(0)) - 1] range from 27.0 for Na to 1.55 reciprocal centipoise for Ni. Viscosities at ratios of expansion V/V(0) = 1.10 vary linearly with squares of solubility parameters DeltaE(v)/V(0), where DeltaE(v) is molal energy of vaporization at the melting point. Viscosities at 10% expansion range from 0.037 cP for Na to 5.38 cP for Co, with some divergence for metals with values of eta in the neighborhood of unity. The good agreement in the case of the transition metals Cu, Fe, Co, and Ni we attribute to distribution of vector momentum among quasi-chemical bonds between d-electrons and vacant orbitals.

鋳造における湯の流動性

鋳造における湯の流動性