Effect of Mo on properties of the industrial Fe–B-alloy-derived Fe-based bulk metallic glasses

The experimental results concerning the effects of Mo on the glass-forming ability(GFA), thermal stability, and mechanical, anticorrosion, and magnetic properties of an(Fe_(71.2)B_(24)Y_(4.8))_(96)Nb_4 bulk metallic glass(BMG) were presented. An industrial Fe–B alloy was used as the raw material, and a series of Fe-based BMGs were synthesized. In BMGs with the Mo contents of approximately 1at%–2at%, the cast alloy reached a critical diameter of 6 mm. The hardness and fracture strength also reached their maximum values in this alloy system. However, the anticorrosion and magnetic properties of the BMGs were not substantially improved by the addition of Mo. The low cost, good GFA, high hardness, and high fracture strength of the Fe-based BMGs developed in this work suggest that they are potential candidates for commercial applications.

Fabrication, tribological and corrosion behaviors of detonation gun sprayed Fe-based metallic glass coating

A metallic glass coating with the composition of Fe51.33Cr14.9Mo25.67Y3.4C3.44B1.26 （mole fraction, %） on the Q235 stainless steel was developed by the detonation gun （D-gun） spraying process. The microstructure and the phase aggregate were analyzed by scanning electron microscopy and X-ray diffractometry, respectively. Microhardness, wear resistance and corrosion behavior were assessed using a Vickers microhardness tester, a ball-on-disk wear testing machine and the electrochemical measurement method, respectively. Microstructural studies show that the coatings possess a densely layered structure with the porosity less than 2.1%. The tribological behavior of the coatings examined under dry conditions shows that their relative wear resistance is five times higher than that of the substrate material. Both adhesive wear and abrasive wear contribute to the friction, but the former is the dominant wear mechanism of the metallic glass coatings. The coatings exhibit low passive current density and extremely wide passive region in 3.5% NaCl solution, thus indicating excellent corrosion resistance.

Corrosion resistance of Fe-based amorphous metallic matrix coating fabricated by HVOF thermal spraying

The Fe-based amorphous metallic matrix coating （Fe-AMMC） was fabricated with the powder mixtures of Fe-based metallic glass synthesized with industrial raw materials, NiCr alloy and WC particle by high velocity oxy-fuel （HVOF） spraying. The corrosion resistance of Fe-AMMC was investigated by potentiodynamic polarization tests in 1 mol/L HCl, NaCl, H2SO4 and NaOH solutions, respectively. The surface morphologies corroded were observed by SEM. The results indicate that Fe-AMMC exhibits excellent corrosion resistance, higher corrosion resistance than 304L stainless steel in the chloride solutions. The low corrosion current density and passive current density of Fe-AMMC with a wide spontaneous passivation region are about 132.0μA/cm2 and 9.0 mA/cm2 in HCl solution, and about 2.5 μA/cm2 and 2.3 mA/cm2 in NaCl solution. The excellent corrosion resistance demonstrates that Fe-based amorphous metallic matrix powder is a viable engineering material in practical anti-corrosion and anti-wear coating applications.

Research progress in friction stir processing of magnesium alloys and their metal matrix surface composites: Evolution in the 21^(st )century

Rising concerns about climate change drive the demand for lightweight components.Magnesium(Mg)alloys are highly valued for their low weight,making them increasingly important in various industries.Researchers focusing on enhancing the characteristics of Mg alloys and developing their Metal Matrix Composites(MMCs)have gained significant attention worldwide over the past decade,driven by the global shift towards lightweight materials.Friction Stir Processing(FSP)has emerged as a promising technique to enhance the properties of Mg alloys and produce Mg-MMCs.Initially,FSP adapted to refine grain size from the micro to the nano level and accelerated the development of MMCs due to its solid-state nature and the synergistic effects of microstructure refinement and reinforcement,improving strength,hardness,ductility,wear resistance,corrosion resistance,and fatigue strength.However,producing defect-free and sound FSPed Mg and Mg-MMCs requires addressing several variables and their interdependencies,which opens up a broad range of practical applications.Despite existing reviews on individual FSP of Mg,its alloys,and MMCs,an attempt has been made to analyze the latest research on these three aspects collectively to enhance the understanding,application,and effectiveness of FSP for Mg and its derivatives.This review article discusses the literature,classifies the importance of Mg alloys,provides a historical background,and explores developments and potential applications of FSPed Mg alloys.It focuses on novel fabrication methods,reinforcement strategies,machine and tool design parameters,material characterization,and integration with other methods for enhanced properties.The influence of process parameters and the emergence of defects are examined,along with specific applications in mono and hybrid composites and their microstructure evolution.The study identifies promising reinforcement materials and highlights research gaps in FSP for Mg alloys and MMCs production.It concludes with significant recommendations for further exploration,reflecting ongoing advancements in this field.

Mitigated reaction kinetics between lithium metal anodes and electrolytes by alloying lithium metal with low-content magnesium

Lithium(Li)metal is regarded as a promising anode candidate for high-energy-density rechargeable batteries.Nevertheless,Li metal is highly reactive against electrolytes,leading to rapid decay of active Li metal reservoir.Here,alloying Li metal with low-content magnesium(Mg)is proposed to mitigate the reaction kinetics between Li metal anodes and electrolytes.Mg atoms enter the lattice of Li atoms,forming solid solution due to the low amount(5 wt%)of Mg.Mg atoms mainly concentrate near the surface of Mg-alloyed Li metal anodes.The reactivity of Mg-alloyed Li metal is mitigated kinetically,which results from the electron transfer from Li to Mg atoms due to the electronegativity difference.Based on quantitative experimental analysis,the consumption rate of active Li and electrolytes is decreased by using Mgalloyed Li metal anodes,which increases the cycle life of Li metal batteries under demanding conditions.Further,a pouch cell(1.25 Ah)with Mg-alloyed Li metal anodes delivers an energy density of 340 Wh kg^(-1)and a cycle life of 100 cycles.This work inspires the strategy of modifying Li metal anodes to kinetically mitigate the side reactions with electrolytes.

Clean production of Fe-based amorphous soft magnetic alloys via smelting reduction of high-phosphorus iron ore and apatite

Separated preparation of prealloys and amorphous alloys results in severe solidification-remelting and beneficial element removal-readdition contradictions,which markedly increase energy consumption and emissions.This study offered a novel strategy for the direct production of FePC amorphous soft magnetic alloys via smelting reduction of high-phosphorus iron ore(HPIO)and apatite.First,the thermodynamic conditions and equilibrium states of the carbothermal reduction reactions in HPIO were calculated,and the element content in reduced alloys was theoretically determined.The phase and structural evolutions,as well as element migration and enrichment behaviors during the smelting reduction of HPIO and Ca_(3)(PO_(4))_(2),were then experimentally verified.The addition of Ca_(3)(PO_(4))_(2)in HPIO contributes to the enrichment of the P element in reduced alloys and the subsequent development of Fe_(3)P and Fe_(2)P phases.The content of P and C elements in the range of 1.52 wt% -14.63 wt% and 0.62 wt% -2.47 wt%,respectively,can be well tailored by adding 0-50 g Ca_(3)(PO_(4))_(2)and controlling the C/O mole ratio of 0.8-1.1,which is highly consistent with the calculated results.These FePC alloys were then successfully formed into amorphous ribbons and rods.The energy consumption of the proposed strategy was estimated to be 2.00×10^(8) kJ/t,which is reduced by 30% when compared with the conventional production process.These results are critical for the comprehensive utilization of mineral resources and pave the way for the clean production of Fe-based amorphous soft magnetic alloys.

Understanding the corrosion of Mg alloys in in vitro urinary tract conditions: A step forward towards a biodegradable metallic ureteral stent

Ureteral stents play a fundamental role in modern time urology. However, following the deployment, stent-related symptoms are frequent and affect patient health and quality of life. Using biodegradable metals as ureteral stent materials have emerged as a promising strategy, mainly due to the improved radial force and slower degradation rate expected. Therefore, this study aimed to characterize different biodegradable metals in urinary tract environment to understand their propensity for future utilization as base materials for ureteral stents. The corrosion of 5 Mg alloys - AZ31, Mg-1Zn, Mg-1Y, pure Mg, and Mg-4Ag - under simulated urinary tract conditions was accessed. The corrosion layer of the different alloys presented common elements, such as Mg(OH)_(2), MgO, and phosphate-containing products, but slight variations in their chemical compositions were detected. The corrosion rate of the different metals varied, which was expected given the differences in the corrosion layers. On top of this, the findings of this study highlighted the significant differences in the samples' corrosion and corrosion layers when in stagnant and flowing conditions. With the results of this study, we concluded that Mg-1Zn and Mg-4Ag presented a higher propensity for localized corrosion, probably due to a less protective corrosion layer;Mg-4Ag corroded faster than all the other four alloys,and Mg-1Y stood out due to its distinct corrosion pattern, that showed to be more homogeneous than all the other four samples, making this one more attractive for the future studies on biodegradable metals.

Development of 3D bicontinuous metal-intermetallic composites through subsequent alloying process after liquid metal dealloying

This study presents a novel process for the fabrication of metal-intermetallic composites with a 3D bicontinuous structure, achieved through a combination of liquid metal dealloying(LMD) and subsequent alloying. Initially, porous Ti structures are produced using the LMD process, followed by immersion in a molten Mg-3Al(wt%) metal. Due to the higher thermodynamic miscibility of Al with Ti compared to Mg, the concentration of Al in the Ti matrix increases as the immersion time increases. This results in a sequential phase transition within the Ti matrix: α-Ti → Ti_(3)Al → Ti Al. The phase transition considerably affects the hardness and strength of the composite material,with the Mg-Ti_(3)Al-Ti Al composite exhibiting a maximum hardness nearly twice as high as that of the conventional Mg-Ti composite. This innovative process holds potential for the development of various bicontinuous metal-intermetallic composites.

Chemical and physical studies of metallic alloy-based old Indian coins with LIBS coupled with multivariate analysis

The present work aims to demonstrate the capabilities of Laser-induced Breakdown Spectroscopy(LIBS)coupled with a multivariate technique for rapid quantification and classification of old Indian coins made of various alloys.Thirteen old Indian coins in different years of circulation,(1922–1986)were selected for the study.The concentrations were determined by Calibration free LIBS(CF-LIBS)method.The concentration of cuprum(Cu)is negligible,and aluminum(Al)is maximum in the first five coins,and vice-versa in the remaining eight coins.Two different multivariate methods,Principal Component Analysis(PCA)and Soft Independent Modelling of Class Analogy(SIMCA)have been used to classify and identify the coins.PCA classified all thirteen samples into four main alloy categories.The discernment of unknown samples to their probable class membership of alloy was performed using SIMCA.The surface hardness(Brinell hardness number)is linearly correlated with the plasma temperature and LIBS intensity ratios.The sample surface of the first and fifth coin belongs to Al-alloy,having the least surface hardness,and it became harder for Cu–Ni alloy,Ni-brass alloy,and bronze alloy.The hardness of the surface is more for bronze sample twelve.It is also observed that the plasma temperature increases monotonically with the Brinell hardness number.This analysis provides valuable information on fabrication methodology and explains large diversification in the elementary composition of old coins.

Glass formation and magnetic properties of Fe-based metallic glasses fabricated by low-purity industrial materials

Fe-based metallic glasses of(Fe74Nb6B20)100?xCrx(x=1,3,5)with high glass forming ability(GFA)and good magneticproperties were prepared using low-purity raw materials.Increasing Cr content does not significantly change glass transitiontemperature and onset crystallization temperature,while it enhances liquidus temperature.The addition of Cr improves the GFA ofthe(Fe74Nb6B20)100?xCrx glassy alloys compared to that in Cr-free Fe?Nb?B alloys,in which the supercooled liquid region(ΔTx),Trgandγare found to be50?54K,0.526?0.538,and0.367?0.371,respectively.The(Fe74Nb6B20)100?xCrx glassy alloys exhibit excellentsoft magnetic properties with high saturation magnetization of139?161A·m2/kg and low coercivity of30.24?58.9A/m.PresentFe?Nb?B?Cr glassy alloys exhibiting high GFA as well as excellent magnetic properties and low manufacturing cost make themsuitable for magnetic components for engineering application.

Microstructure and Mechanical Properties of Resistance Spot Welds for Fe-based Metallic Glass

The lap joints of Fe-based metallic glass ribbons were carried by resistance spot welding, and the microstructures of spot welds were investigated by X-ray diffraction and transmission electron microscopy. The results indicated that the perfect formations of joints without typical defects such as spatter were achieved with optimized parameters. Except for little nano-particle Fe2B, no other crystalline particle was detected by TEM, revealing that the most microstructure in spot weld remains amorphous. The maximum tensile-shearing force was 45.0 N with the optimized parameters of 1 kA weld current, 30 N electrode force and 0.02 ms weld time. The spot weld failed as pullout failure mode propagating along the interface of nugget zone. The study demonstrates that resistance spot welding is an effective and practical welding process for Fe-based metallic glass.

Ab initio molecular dynamics simulations of nano-crystallization of Fe-based amorphous alloys with early transition metals

The addition of early transition metals(ETMs)into Fe-based amorphous alloys is practically found to be effective in reducing theα-Fe grain size in crystallization process.In this paper,by using ab initio molecular dynamics simulations,the mechanism of the effect of two typical ETMs(Nb and W)on nano-crystallization is studied.It is found that the diffusion ability in amorphous alloy is mainly determined by the bonding energy of the atom rather than the size or weight of the atom.The alloying of B dramatically reduces the diffusion ability of the ETM atoms,which prevents the supply of Fe near the grain surface and consequently suppresses the growth ofα-Fe grains.Moreover,the difference in grain refining effectiveness between Nb and W could be attributed to the larger bonding energy between Nb and B than that between W and B.

Effect of casting vacuum on thermodynamic and corrosion properties of Fe-based glassy alloy

The effect of casting vacuum on thermodynamic and corrosion properties of Fe61Co7Zr8Mo5W2B17 in shape of cylinder of 3 mm in diameter and ribbon of 20?40μm in thickness and 2?3 mm in width were investigated with X-ray diffraction (XRD), differential scanning calorimetry (DSC), dilatometer (DIL), scanning electron microscopy (SEM) and electrochemical station. It is found that high casting vacuum can improve the glass forming ability (GFA), the contraction degree during heating, and the pitting resistance of the glassy alloy, which can be ascribed to the fact that the dissolution of tungsten in the melt is improved under the high casting vacuum.

Nano silica aerogel-induced formation of an organic/alloy biphasic interfacial layer enables construction of stable high-energy lithium metal batteries

Lithium metal batteries represent promising candidates for high-energy-density batteries, however, many challenges must still be overcome,e.g., interface instability and dendrite growth. In this work, nano silica aerogel was employed to generate a hybrid film with high lithium ion conductivity(0.6 mS cm^(-1)at room temperature) via an in situ crosslinking reaction. TOF-SIMS profile analysis has revealed conversion mechanism of hybrid film to Li–Si alloy/Li F biphasic interface layer, suggesting that the Li–Si alloy and Li F-rich interface layer promoted rapid Li+transport and shielded the Li anodes from corrosive reactions with electrolyte-derived products. When coupled with nickel-cobalt-manganese-based cathodes, the batteries achieve outstanding capacity retention over 1000 cycles at 1 C. Additionally the developed film coated on Li enabled high coulombic efficiency(99.5%) after long-term cycling when coupled with S cathodes. Overall, the results presented herein confirm an effective strategy for the development of high-energy batteries.

Surface hardening of Fe-based alloy powders by Nd:YAG laser cladding followed by electrospark deposition with WC-Co cemented carbide

This paper presents the results of a study concerned with the surface hardening of Fe-based alloys and WC-8Co cemented carbide by inte- grating laser cladding and the electrospark deposition processes. Specimens of low carbon steel were processed firstly by laser cladding with Fe-based alloy powders and then by electrospark deposition with WC-SCo cemented carbide. It is shown that, for these two treatments, the electrospark coating possesses finer microstructure than the laser coating, and the thickness and surface hardness of the electrospark coating can be substantially increased.

Microstructural evolution and intermetallic formation in Al-8wt% Si-0.8wt% Fe alloy due to grain refiner and modifier additions

An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that a-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.

In situ laser deposition of NiTi intermetallics for corrosion improvement of Ti-6Al-4V alloy

NiTi intermetallic coatings were fabricated on the surface of Ti-6Al-4V alloy by melting Ni and Ti powders using laser metal deposition（LMD） process.The effects of NiTi reinforcement content on the microstructure,hardness and corrosion properties of the coatings were examined.The results show that the deposited coatings are characterized by NiTi,NiTi2 and NiTi3 intermetallic phases.An appreciable increase in corrosion resistance is obtained for all the coatings,and Ti55Ni45 coating shows the highest corrosion resistance;while coatings Ti50Ni50 and Ti45Ni55 follow in that succession.The reinforcement materials are proven to be corrosion resistant in the tested environment,and the effect of Ti is more dominant.

Microstructure and thermal properties of dissimilar M300–CuCr1Zr alloys by multi-material laser-based powder bed fusion

Multi-material laser-based powder bed fusion (PBF-LB) allows manufacturing of parts with 3-dimensional gradient and additional functionality in a single step. This research focuses on the combination of thermally-conductive CuCr1Zr with hard M300 tool steel.Two interface configurations of M300 on CuCr1Zr and CuCr1Zr on M300 were investigated. Ultra-fine grains form at the interface due to the low mutual solubility of Cu and steel. The material mixing zone size is dependent on the configurations and tunable in the range of0.1–0.3 mm by introducing a separate set of parameters for the interface layers. Microcracks and pores mainly occur in the transition zone.Regardless of these defects, the thermal diffusivity of bimetallic parts with 50vol% of CuCr1Zr significantly increases by 70%–150%compared to pure M300. The thermal diffusivity of CuCr1Zr and the hardness of M300 steel can be enhanced simultaneously by applying the aging heat treatment.

New insights on the high-corrosion resistance of UHP Mg-Ge alloys tested in a simulated physiological environment

UHP Mg-Ge alloys was recently found to provide excellent corrosion resistance.This paper provides new insights on the mechanism of improved corrosion resistance of UHP Mg-Ge alloys in Hanks’solution.The studied UHP Mg-0.5Ge and UHP Mg-1Ge alloys showed superior corrosion resistance compared to UHP Mg and WE43,with the Mg-1Ge exhibiting the best corrosion performance.The exceptional corrosion resistance of the UHP alloy is attributed to(i)Mg_(2)Ge’s ability to suppress cathodic kinetics,(ii)Ge’s capability to accelerate the formation of a highly passive layer,and the(iii)low amounts of corrosion-accelerating impurities.

Theoretical investigations of half-metallic ferromagnetism in new Half-Heusler YCrSb and YMnSb alloys using first-principle calculations

Structural,electronic,and magnetic properties of new predicted half-Heusler YCrSb and YMnSb compounds within the ordered MgAgAs Clb-type structure are investigated by employing first-principal calculations based on density functional theory.Through the calculated total energies of three possible atomic placements,we find the most stable structures regarding YCrSb and YMnSb materials,where Y,Cr(Mn),and Sb atoms occupy the(0.5,0.5,0.5),(0.25,0.25,0.25),and(0,0,0) positions,respectively.Furthermore,structural properties are explored for the non-magnetic and ferromagnetic and anti-ferromagnetic states and it is found that both materials prefer ferromagnetic states.The electronic band structure shows that YCrSb has a direct band gap of 0.78 eV while YMnSb has an indirect band gap of 0.40 eV in the majority spin channel.Our findings show that YCrSb and YMnSb materials exhibit half-metallic characteristics at their optimized lattice constants of 6.67 and 6.56 ,respectively.The half-metallicities associated with YCrSb and YMnSb are found to be robust under large in-plane strains which make them potential contenders for spintronic applications.