Magnesium alloys as alternative anode materials for rechargeable magnesium-ion batteries:Review on the alloying phase and reaction mechanisms

Magnesium-ion batteries(MIBs)are promising candidates for lithium-ion batteries because of their abundance,non-toxicity,and favorable electrochemical properties.This review explores the reaction mechanisms and electrochemical characteristics of Mg-alloy anode materials.While Mg metal anodes provide high volumetric capacity and dendrite-free electrodeposition,their practical application is hindered by challenges such as sluggish Mg^(2+)ion diffusion and electrolyte compatibility.Alloy-type anodes that incorporate groups XIII,XIV,and XV elements have the potential to overcome these limitations.We review various Mg alloys,emphasizing their alloying/dealloying reaction mechanisms,their theoretical capacities,and the practical aspects of MIBs.Furthermore,we discuss the influence of the electrolyte composition on the reversibility and efficiency of these alloy anodes.Emphasis is placed on overcoming current limitations through innovative materials and structural engineering.This review concludes with perspectives on future research directions aimed at enhancing the performance and commercial viability of Mg alloy anodes and contributing to the development of high-capacity,safe,and cost-effective energy storage systems.

Visualization and simulation of plastic material flow in friction stir welding of 2024 aluminium alloy plates

Thin copper sheets as marker material were embedded into weld path of 2024 aluminium alloy plates and their final position after friction stir welding was examined by metallographic techniques. Referring to the visualized material flow patterns, a three-dimensional model was developed to conduct the numerical simulation of the temperature profile and plastic material flow in friction stir welding. The calculated velocity contour of plastic flow in close proximity of the tool is generally consistent with the visualized results. As the tool rotation speed increases at a constant tool travel speed, the material flow near the pin gets stronger. The predicted shape and size of the weld nugget zone match with the experimentally measured ones.

Influence of alloy components on arc erosion morphology of Ag/MeO electrical contact materials

Arc erosion morphologies of Ag/MeO（10） electrical contact materials after 50000 operations under direct current of 19 V and 20 A and resistive load conditions were investigated using scanning electron microscope（SEM） and a 3D optical profiler（3DOP）. The results indicated that 3DOP could supply clearer and more detailed arc erosion morphology information. Arc erosion resistance of Ag/SnO_2（10） electrical contact material was the best and that of Ag/CuO（10） was the worst. Arc erosion morphology of Ag/MeO（10） electrical contact materials mainly included three different types. Arc erosion morphologies of Ag/ZnO（10） and Ag/SnO_2（10） electrical contact materials were mainly liquid splash and evaporation, and those of Ag/CuO（10） and Ag/CdO（10） were mainly material transfer from anode to cathode. Arc erosion morphology of Ag/SnO_2（6）In_2O_3（4） electrical contact materials included both liquid splash, evaporation and material transfer. In addition, the formation process and mechanism on arc erosion morphology of Ag/MeO（10） electrical contact materials were discussed.

Material driven workability simulation by FEM including 3D processing maps for magnesium alloy

The three-dimensional （3D） processing maps considering strain based on the two-dimensional （2D） processing maps proposed by PRASAD can describe the distribution of the efficiency of power dissipation and flow instability regions at various temperatures, strain rates and strains, which exhibit intrinsic workability related to material itself. Finite element （FE） simulation can obtain the distribution of strain, strain rate, temperature and die filling status, which indicates state-of-stress （SOS） workability decided by die shape and different processing conditions. On the basis of this, a new material driven analysis method for hot deformation was put forward by the combination of FE simulation with 3D processing maps, which can demonstrate material workability of the entire hot deformation process including SOS workability and intrinsic workability. The hot forging process for hard-to-work metal magnesium alloy was studied, and the 3D thermomechanical FE simulation including 3D processing maps of complex hot forging spur bevel gear was first conducted. The hot forging experiments were carried out. The results show that the new method is reasonable and suitable to determine the aoorooriate nrocess narameters.

Synchrotron radiation-based materials characterization techniques shed light on molten salt reactor alloys

From a safety point of view, it is important to study the damages and reliability of molten salt reactor structural alloy materials, which are subjected to extreme environments due to neutron irradiation, molten salt corrosion, fission product attacks, thermal stress, and even combinations of these. In the past few years, synchrotron radiation-based materials characterization techniques have proven to be effective in revealing the microstructural evolution and failure mechanisms of the alloys under surrogating operation conditions. Here, we review the recent progress in the investigations of molten salt corrosion,tellurium(Te) corrosion, and alloy design. The valence states and distribution of chromium(Cr) atoms, and the diffusion and local atomic structure of Te atoms near the surface of corroded alloys have been investigated using synchrotron radiation techniques, which considerably deepen the understandings on the molten salt and Te corrosion behaviors. Furthermore, the structure and size distribution of the second phases in the alloys have been obtained, which are helpful for the future development of new alloy materials.

AN IN SITU SURFACE COMPOSITE AND GRADIENT MATERIAL OF Al-Si ALLOY PRODUCED BY ELECTROMAGNETIC FORCE

Because of the different conductivities between the primary phase (low electric conduc tivity) and the metal melt, electromagnetic force scarcely acts on the primary phase. Thus, an electromagnetic repulsive force applied by the metal melt exerts on the pri mary phase when the movement of the melt in the direction of electromagnetic force is limited. As a result, the repulsive force exerts on the primary phase to push them to move in the direction opposite to that of the electromagnetic force when the metal melt with primary phase solidifies under an electromagnetic force field. Based on this, a new method for production of in situ surface composite and gradient material by electromagnetic force is proposed. An in situ primary Si reinforced surface composite of Al-15wt%Si alloy and gradient material of Al-l9wt%Si alloy were produced by this method. The microhardness of the primary Si is HV1320. The reinforced phase size is in the range from 40μm to 100μm. The wear resistance of Al-Si alloy gradient material can be more greatly increased than that of their matrix material.

Experimental study on the influences of cutter geometry and material on scraper wear during shield TBM tunnelling in abrasive sandy ground

When shield TBM tunnelling in abrasive sandy ground,the rational design of cutter parameters is critical to reduce tool wear and improve tunnelling efficiency.However,the influence mechanism of cutter parameters on scraper wear remains unclear due to the lack of a reliable test method.Geometry and material optimisation are often based on subjective experience,which is unfavourable for improving scraper geological adaptability.In the present study,the newly developed WHU-SAT soil abrasion test was used to evaluate the variation in scraper wear with cutter geometry,material and hardness.The influence mechanism of cutter parameters on scraper wear has been revealed according to the scratch characteristics of the scraper surface.Cutter geometry and material parameters have been optimised to reduce scraper wear.The results indicate that the variation in scraper wear with cutter geometry is related to the cutting resistance,frictional resistance and stress distribution.An appropriate increase in the front angle(or back angle)reduces the cutting resistance(or frictional resistance),while an excessive increase in the front angle(or back angle)reduces the edge angle and causes stress concentration.The optimal front angle,back angle and edge angle for quartz sand samples areα=25°,β=10°andγ=55°,respectively.The wear resistance of the modelled scrapers made of different metal materials is related to the chemical elements and microstructure.The wear resistances of the modelled scrapers made of 45#,06Cr19Ni10,42CrMo4 and 40CrNiMoA are 0.569,0.661,0.691 and 0.728 times those made of WC-Co,respectively.When the alloy hardness is less than 47 HRC(or greater than 58 HRC),scraper wear decreases slowly with increasing alloy hardness as the scratch depth of the particle asperity on the metal surface stabilizes at a high(or low)level.However,when the alloy hardness is between 47 HRC and 58 HRC,scraper wear decreases rapidly with increasing alloy hardness as the scratch depth transitions from high to low levels.The sensitive hardness interval and recommended hardness interval for quartz sand are[47,58]and[58,62],respectively.The present study provides a reference for optimising scraper parameters and improving cutterhead adaptability in abrasive sandy ground tunnelling.

A review of classical hydrogen isotopes storage materials

Hydrogen storage alloys(HSAs)are attracting widespread interest in the nuclear industry because of the generation of stable metal hydrides after tritium absorption,thus effectively preventing the leakage of radioactive tritium.Commonly used HSAs in the hydrogen isotopes field are Zr2M(M=Co,Ni,Fe)alloys,metallic Pd,depleted U,and ZrCo alloy.Specifically,Zr2M(M=Co,Ni,Fe)alloys are considered promising tritium-getter materials,and metallic Pd is utilized to separate and purify hydrogen isotopes.Furthermore,depleted U and ZrCo alloy are well suited for storing and delivering hydrogen isotopes.Notably,all the aforementioned HSAs need to modulate their hydrogen storage properties for complex operating conditions.In this review,we present a comprehensive overview of the reported modification methods applied to the above alloys.Alloying is an effective amelioration method that mainly modulates the properties of HSAs by altering their local geometrical/electronic structures.Besides,microstructural modifications such as nano-sizing and nanopores have been used to increase the specific surface area and active sites of metallic Pd and ZrCo alloys for enhancing de-/hydrogenation kinetics.The combination of metallic Pd with support materials can significantly reduce the cost and enhance the pulverization resistance.Moreover,the poisoning resistance of ZrCo alloy is improved by constructing active surfaces with selective permeability.Overall,the review is constructive for better understanding the properties and mechanisms of hydrogen isotope storage alloys and provides effective guidance for future modification research.

A MOLD MATERIAL USED FOR TITANIUM-ALUMINUM ALLOY-CALCIA

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Effect of welding speed on the material flow patterns in friction stir welding of AZ31 magnesium alloy

The clear zigzag-line pattern on transverse cross sections can be used to explain the formation mechanism of the weld nugget when friction stir welded AZ31 magnesium alloy without any other insert material is used as mark. It provides a simple and useful method to research the joining mechanism of friction stir welding. The rotation speed is kept at 1000 r/min and the welding speed changes from 120 mm/min to 600 mm/min. The macrostructure on the transverse cross section was divided into several parts by faying surface. The results show that the shape and formation procedure of the weld nugget change with the welding speed. There are two main material flows in the weld nugget： one is from the advancing side and the other is from the retreating side. A simple model on the weld nugget formation of FSW is presented in this article.

Research on arc erosion of silver-based alloy contact materials under low voltage,resistive load and small current at 400 Hz and 50 Hz

By using a self-developed IF power and a ASTM contact material experimental system of small-capacity and variable frequency,the value of arcing characteristics and the welding force of the silver-based contact material are acquired under low voltage,resistive load and small current at 400 Hz and 50 Hz. By means of an electricity-ray analytical balance,SEM and EDAX,the weighing values of the contact materials and the changes of AgCdO,AgNi,AgC and AgW contact material surface profile and micro-area constituent are obtained and analyzed. The arc erosion causes of silver-based alloy contact materials at 400 Hz and 50 Hz are also discussed.

Correlation between Single Factor Material Constitutive Model Parameters and Temperature for Ti6Al4V Alloy

Accurate material constitutive model is considered highly necessary to perform finite element simulation and analysis.However,it is difficult to establish the material constitutive model because of uncertainty of mathematical relationship and constraint of existing experimental condition.At present,there exists considerable gap between finite element simulation result and actual cutting process.Particular emphases were put on investigating the correlation between ＂single factor＂ material constitutive model parameters and temperature for Ti6Al4V alloy,and also establishment of material constitutive model for this kind of material.Theoretical analyses based on dislocation theory and material functional relations showed that material model was deeply affected by variation temperature.By the least squares best fit to the available quasi-static and high-speed impact compression experiment data,material parameters at various temperatures were found.Experimental curves analyses and material parameters comparison showed that the ＂single factor＂ material constitutive model parameters were temperature dependent.Using the mathematical mapping between material parameters and temperature,＂single factor＂ material constitutive model of Ti6Al4V alloy was established,which was proven to be right by comparing with experimental measurements.This work makes clear that the ＂single factor＂ material constitutive model parameters of Ti6Al4V alloy are temperature dependent.At the same time,an accurate material constitutive model is established,which helps to optimize cutting process and control machining distortion for Ti6Al4V alloy aerospace parts.

Multirange Fractals in Materials: Applications to Fracture and Mechanical Alloying under Ball Milling

A new model of multirange fractals is proposed to explain the experimental results observed on the fractal dimensions of the fractured surfaces in materials. A new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It shows the importance of fractorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals. Mechanical alloying process under ball milling as a non-equilibrium dynamical system has been also analyzed.

Thermodynamic Analysis on Interaction between Molten Ti Alloys and Oxide Molding Materials

A thermodynamic model has been built up for the interactions between molten Ti alloys and oxide molding materials in the way of decomposition and solution of molding materials, then the influences on the reaction free energy changes have been calculated and discussed.

Hydriding and Dehydriding Characteristics of Mechanically Alloyed LaMg_(17) Ni Composite Material

A composite material with the nominal composition LaMg 17 Ni was synthesized by mechanical alloying and the hydriding/dehydriding (H/D) behaviors of this material were studied at several temperatures. This material has a hydrogen storage capacity (5.76% H 2, mass fraction) lower than conventionally alloyed La 2Mg 17 (6.63% H 2, mass fraction) without activation but shows a superior hydriding/dehydriding kinetic property. At 523 K it absorbed 4.97% (mass fraction) in less than 1 min , approximately 100 times faster than La 2Mg 17 alloy under the same conditions. This attractive kinetic property of the alloy can be ascribed to the catalytic action of Mg 2Ni, LaH 2 and La as well as the multiphase structure formed in the preparation processes. The relationships between the equilibrium plateau pressure and the temperature can be expressed as lg p eq =-2797/ T +4.267 (553 K≤ T ≤623 K) for hydriding and lg p eq =-3957/ T +6.063(553 K≤ T ≤623 K) for dehydriding.

Effect of mould material on aluminum alloy ingot quality under low frequency electromagnetic casting

With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that magnetic flux density and electromagnetic body force in the aluminum melt are greatly increased when the external part of mould is made from A3 steel. A low-frequency electromagnetic casting 6063 aluminum alloy experiment was conducted in the laboratory with the current value of 120 A and frequency value of 15 Hz. The experiment showed that the microstructure and surface quality of ingots with mould outer part made from A3 steel under low-frequency electromagnetic field are better than that of ingots with mould outer part made from austenitic stainless steel. The surface of the ingots with mould outer part made from A3 steel is smooth and free from exudations and cold shut defects. The as-cast microstructure consists of fine, uniformly distributed equiaxed grains.

High Temperature Mechanical Properties of Ni-Al-Cr Based Alloys for Advanced Die-Materials Applications

In this study, we report on advanced Ni3Al based high temperature structural alloys with Zr and B addition in order to apply in the fields of die-casting and high temperature press forming as die materials. Microstructures and mechanical properties of Ni3Al based intermetallic alloys produced by vacuum arc melting were investigated in terms of phase analysis by using a scanning electron microscope （SEM） equipped with an X-ray energy dispersive spectrometer （EDS）, an X-ray diffractometer （XRD） and tensile test. The duplex microstructural feature consisting of γ＇ matrix phase and small intermetallic dispersoids was observed to be distributed over the whole microstructure. The ultimate tensile strength of the present alloy was superior to commercial iron-based and Ni-based die-materials especially in the high temperature region.

Preparation and Characterization of Rare Earth Metal and Alloy Target Materials for Manufacturing Magneto-Optical Disks

The studies were made on the preparation processes of the rare earth metal and alloy target materials and their characterization. In this work the rare earth metals were prepared by electrolysis of the oxide in molten salt for Nd metal and metallothermic reduction of the fluorides for Gd, Tb, Dy metals. After vacuum refining and distillation purification these rare earth metals were used for manufacturing the element targets, mosaic targets and as the starting materials of preparing the rare earth-transition metal (RE-TM) alloy targets. The four kinds of Dy-FeCo, NdDy-FeCo, Tb-FeCo and GdTb-FeCo alloy targets with diameter of 100 mm and thickness of 3 mm were prepared using powder metallurgical technique. The oxygen content and microstructure of the prepared RE-TM cast alloys and sintered targets were analyzed. The features and requirements of the RE-TM alloy sputtering target materials were also discussed.

Feasibility Study on V Fe Alloy Slag as Abrasive Material

The possibility of using V-Fe alloy slag as abrasive material was investigated. The chemical constitution and microstructure of the V-Fe alloy slag were examined. It is found that the slag contains about 90% Al2O3 existing as corundum with high hardness (> 30 GPa) and high bulk density (> 3.6 g/cm(3)). The V-Fe alloy slag can be applied to abrasive material instead of brown alumina (or black alumina).

Effect of Counterface Materials on Friction and Wear Behavior of Double Glow Glasma Discharge Surface Alloying on Ti22Al25Nb Alloy

Samples of surface chromising layer were prepared by the double glow plasma discharge technique. X-ray diffraction and X-ray photoelectron spectroscopy（XPS） analysis of dif-ferent elements confirmed the formation of chrome in the layer. Their tribological properties were investigated by pin-on-disk tribometer. Silicon nitride, GCr15, and nickel-based alloy were selected as counterface materials. Results indicated that the lowest friction coefficients and wear rate were ob-tained when substrate and chromising layer against nickel-based alloy, and tribological properties of chromising layer were better than those of substrate. The highest friction and wear rate were samples against silicon nitride alloys. In the case of three rubbing pairs, the unchangeable materials against different hardness counterfaces leaded to different wear mechanisms. Samples against silicon nitride exhibited abrasive mechanism, and when GCr15 and nickel-based alloy were used as counterface, transfer film and glaze layer formed on the contact surface, which played the main role in decreasing friction and wear.