Bimetallic Component Research Articles

The Influence of the Parameters of the Skew Rolling Process for Bimetallic Elements on the Mechanical Properties and Structure of Materials.

This paper presents selected results of theoretical and experimental research into the manufacture of axisymmetric bimetallic components using three-tool skew rolling technology. In the tests, it was assumed that the outer layer would be a material intended for heat treatment. However, low-carbon steel was used for the core. Experimental investigations were carried out in an innovative CNC skew rolling mill. Tests were carried out at different technological parameters of the process. In addition, the geometric parameters of the billet and the way it was heated were analyzed in relation to the quality of the resulting weld between the two materials. The quality of the weld was assessed based on metallographic observation and on strength tests (shear method). On the other hand, theoretical studies were based on numerical modeling (FEM). The numerical analysis made it possible to determine the distribution of temperature, deformation and stress in the rolling bimetallic component. The results obtained indicated that it is possible to produce bimetallic materials from the proposed steel grades. In addition, a significant effect of the method of heating the billet in the chamber furnace on the microstructure in the joining zone and the shear strength was found. There was an increase in Rc strength of about 35% when using oxidation protection. The results indicated better strength when the billet is rolling with a smaller outer layer thickness (about 50 MPa). This was confirmed by the results obtained from the FEM analysis, which indicated higher values of plastic strain and the occurrence of higher compressive stresses in the near-surface zones of the rolled bimetallic forging, both of which facilitate the welding process. From the temperature distribution (in the range of (600-1200) °C) obtained during the rolling of the bimetal forging, it can be seen that contact with cold tools does not affect the temperature in the welding zone.

Processing, Microstructure, and Properties of Bimetallic Steel-Ni Alloy Powder HIP

This work explores technical feasibility in hot isostatic pressing (HIP) manufacturing of an integral bimetallic component using steel and Ni alloy powder for supercritical carbon dioxide (sCO2) turbomachinery. Lab-scale bimetallic HIP specimens using HAYNES® 282® and SS316L or SS415 powder are investigated in powder configuration, heat treatment, microstructure, and tensile properties up to 400 °C. Interdiffusion profiles at dissimilar alloy interfaces caused by HIP cycle is predicted by DICTRA simulations and validated by electron probe microanalysis (EPMA). The interdiffusion distance of most elements is around 100 μm, while C and N have a higher interdiffusion distance. Dense distribution of Ti-rich carbonitrides and alumina particles are found to decorate prior particle boundaries near joining interface on the 282 side, affecting tensile strength across interface as well as tensile failure location. A higher amount of excessive carbonitride formation near interface is observed in SS316L/282 than in SS415/282, which is consistent with the predicted greater degree of interdiffusion effect in SS316L/282. Typical HAYNES® 282® heat treatment condition is applicable to 282/SS316L and 282/SS415 combinations, resulting in a higher strength than cast CF8M and CA6NM. A pilot-scale bimetallic SS415/282 pipe is then demonstrated to show the promise of scaleup.

Improved strength in nickel‑aluminum bronze/steel bimetallic component fabricated using arcing-wire arc additive manufacturing with alternating deposition strategy

To enhance microstructure and mechanical properties, arcing-wire arc additive manufacturing (AWAAM) with alternating deposition strategy was firstly employed to produce nickel‑aluminum bronze (NAB)-steel components. The implementation of alternating deposition strategy fostered the creation of interlocked microstructures, establishing robust bonds at the interface. Moreover, the convection within the melt pool during alternating deposition induced the formation of numerous precipitates, serving as a precipitation reinforcement. Simultaneously, these precipitates served as heterogeneous nucleation sites, facilitating the formation of substantial fine equiaxed crystals, resulting in grain boundary strengthening. A comprehensive examination of microstructure and mechanical properties was conducted using a variety of microscopy techniques and mechanical testing for components with and without arcing-wire. After applying arcing-wire, precise control was exerted over the melting of both matrix and wire, effectively preventing interface cracking caused by excessive melting. Moreover, with the arc heat input diminished, the temperature gradient in the melt pool decreased, leading to grain and precipitate refinement, consequently enhancing their strength. Owing to microstructural modifications, AWAAM demonstrated enhancements in ultimate tensile strength and yield strength by up to 20.1 % and 21.1 %, respectively, when compared to WAAM.

Selective crack propagation in steel-nickel component printed by wire arc directed energy deposition

Steel-nickel bimetallic structures exhibit attractive site-specific properties, but it is challenging to fabricate large a monolithic component while maintaining the dense regular interface that enable their properties. This study proposed a criss-crossed interface in steel (316L stainless steel) – nickel (IN 718 alloy) bimetallic component, with in-situ microstructure interlocking and improved mechanical response. A difference in physical properties between these two materials creates cracks at their interface where were fully explored using metallographic examination and numerical simulation. It is found cracks easily occur at their interface near nickel side due to alternate thermal cycles that lead to a variation in residual stress and microstructure, including grain orientation, texture strength, dislocation density and Schmid factors. The research outcomes enable better understanding of crack initiation mechanism in bimetallic structures printed by arc-based metal additive manufacturing and may advance the design and fabrication of advanced structures.

Revealing bimetallic synergy in van der Waals AgInP2Se6 nanosheets for alkali metal ion battery electrodes

We report two-dimensional AgInP2Se6 (AIPSe) bimetallic phosphorus trichalcogenides nanosheets as anodes for advanced alkali metal ion batteries (AMIBs). The intrinsic layered architecture of this compound not only facilitates rapid charge propagation but also accentuates ion storage due to its expansive surface area. The integration of the bimetallic component results in a synergistic enhancement in electronic/ionic conductivity and optimizes the redox dynamics of multi-electronic materials, eventually attaining superior electrochemical characteristics. Moreover, the accompanying deposition of metallic silver during electrochemical processes reduces battery polarization, while the presence of metallic indium acts as an efficacious structural stabilizer, effectively inhibit dendrite proliferation. As an anode electrode coupled with graphite (G) in lithium-ion (LIBs) and potassium-ion batteries (PIBs), AIPSe@G anodes for LIBs achieve 707.8 mA h g−1 at 0.1 A g−1, retain over 900 cycles at 2.0 A g−1, and demonstrate 318.5 mA h g−1 at 3.0 A g−1 rate capability. For PIBs, they reach 480.3 mA h g−1 at 25.0 mA g−1, sustains for 550 cycles at 250 mAg−1, and offers 214.2 mA h g−1 at 3.0 A g−1 rate performance. Comprehensive full cell tests further endure 100 cycles in both LIBs and PIBs under diverse current regimes. Our study pioneers a new direction for AMIB anode materials, emphasizing the advantages of integrating bimetallic features into two-dimensional frameworks to boost electrode dynamics and achieve consistent conversion reactions.

Fabrication of hierarchical flower-like NiMo bimetallic catalyst for valorization of biomass platforms

The rational design of catalysts with 3D open structures is vitally important to enhance catalytic performance through exposing the active sites. Herein, the hierarchical flower-like Ni-Mo bimetallic catalyst was constructed by using levulinic acid to synthesize γ-valerolactone as the template reaction and nitrogen-rich dual ligand MOF as the self-sacrificial template. Benefiting from the anchoring effect of N–C defects, the Ni-Mo bimetallic component was uniformly dispersed on the petal-shape nanosheets. The characterization results confirmed the doped Mo facilitated the formation of NiMo-Nx and MoO2 sites, and thus improved the dispersion of Ni species and the acidity of the catalyst. Density Functional Theory (DFT) calculations results confirmed that NiMo-Nx was more conducive to the dissociation of H2 than Ni and NiMo species. And, Ni-MoO2 interface could facilitate the activation and cleavage of the C–O in carbonyl group of levulinic acid. The synergy between the hydrogenation sites (NiMo-Nx) and the Lewis acid sites (Ni-MoO2 interface) enabled the catalyst excellent performance for the valorization of levulinic acid to γ-valerolactone in aqueous phase. In addition, the reaction mechanism was given according to the reaction results and DFT calculation results.

Amorphous interfacial microstructure and high bonding strength in Al-Fe bimetallic components enabled by a large-area solid-state additive manufacturing technique

There is a growing demand for the ability to manufacture large-scale aluminum-steel (Al-Fe) bimetallic components for realizing the enormous advantages of advanced multi-material structures which offers effective lightweighting and increasingly smart functionalities. The formation of brittle intermetallic compounds (IMCs) at the bonding interface has been the major barrier to safety-critical applications with existing manufacturing processes, including additive manufacturing techniques. This study showed that a combination of a novel modified friction stir additive manufacturing (M-FSAM) and pre-processing surface polishing of the stainless steel enables the formation of a relative homogenously distributed nanoscale amorphous layer along the bonding interface between the 6061 Al and the 304 stainless steel. As a result, the high interfacial bonding strength of 280 MPa was achieved. Compared to the existing friction stir welding/AM processes, M-FSAM enables a significant increase in tool traverse speed and a remarkable reduction in tool cost for Al-Fe bimetallic component manufacturing. The nanoscale amorphous layer consisted of a continuous O and Mg rich layer 10–20 nm in thickness and a discontinuous Al-Fe-Si layer 50–100 nm in thickness. The O and Mg rich layer consisted of an amorphous matrix with nanocrystalline precipitates while the Al-Fe-Si layer consisted of a q-glass with some degree of crystallinity. The formation mechanism of the unique Al-Fe interfacial microstructure was analyzed in detail in this study.

PdRh bimetallene for energy-saving hydrogen production via methanol electroreforming

Optimization of the component and structure is a powerful strategy to enhance electrocatalytic performance of metallene. Herein, a facile and effective thermal-solvent approach is proposed for the synthesis of defect-rich and wrinkled PdRh bimetallene. The PdRh bimetallene exhibits superior electroactivity and durability in alkaline hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). Benefiting from defect-rich and curved metallene structure, the PdRh bimetallene possesses ultrahigh specific surface area, exposed active sites, high conductivity and atomic utilization. Moreover, the bimetallic component effectively adjusts the electronic structure, optimizing the adsorption and dissociation of substances during electrocatalysis. The HER-MOR two-electrolysis system for PdRh bimetallene exhibits high energy conversion efficiency, requiring an only 0.657 V to reach a current density of 10 mA cm−2 for energy-efficient hydrogen (H2) production, which significantly decreases energy consumption compared with conventional water electrolysis. The proposed approach provides a promising strategy to design bimetallic metallene for energy electrocatalytic applications.

Electroreduction of nitrogen to ammonia over bimetallic mesoporous RuAu film

Electrochemical synthesis of ammonia is regarded as an appealing substitute to the Haber-Bosch method owing to its mild condition and reduced energy consumption, while its efficiency still needs further optimization and exploration. Here, bimetallic mesoporous RuAu film is grown on Ni foam (mRuAu/NF) by micelle-assisted electrodeposition. The bimetallic component can strengthen the nitrogen adsorption on the catalyst, and the mesoporous structure provides abundant active sites and facilitated transfer channels for the adsorption and activation of nitrogen. Thus, mRuAu/NF possesses excellent activity and efficiency in 0.1 M Na2SO4 (NH3 yield: 27.98 μgh/mgcat.; Faraday efficiency: 19.82%). This research presents a general synthetic method for the preparation of self-supported mesoporous alloy film, which makes a great contribution to nitrogen reduction reaction.

Experimental and theoretical study of bifunctional electro-catalysts constructed from different Polyoxometalates and Ag-bimpy segments

In this work, upon subtle POMs variation, we reported on the assembly and performances of three new bimetallic component organic-inorganic hybrids, [Ag2(bimpy)(VV2O6)](1), [Ag3(bimpy)2(β-MoVI8O26)](2), [Ag4(bimpy)2(H2O)2(α-SiWVI12O40)]•2H2O (3) (bimpy = 3,5-bis(1-imidazoly) pyridine). Compound 1 with 3D framework structure is featured by {-V-O-V-}n helical chains, {Ag3} clusters and {bimpy-Ag-bimpy} units. Compound 2 has a 3,3,6,6-connected 3D architecture with the (43)(43)(42•69•7•83)(46•52•64•7•82) topology. Compound 3 has a 3,3,4-connected 2D layer with (62•8)(62•8)(66) topology. The electrochemical and bifunctional electro-catalytic activities of three compounds have been conducted. The experimental results show that β–[Mo8O26]4− hybrid displays better electrocatalytic performance than [V2O6]2− and Keggin-type hybrids for reduction of nitrite, while [V2O6]2− hybrid exhibits better electrocatalytic activity than β–[Mo8O26]4- and Keggin hybrids towards oxidations of ascorbic acid. Furthermore, the molecular electrostatic potential and frontier molecular orbital were performed.

Hydrogen evolution reaction in an alkaline environment through nanoscale Ni, Pt, NiO, Fe/Ni and Pt/Ni surfaces: Reactive molecular dynamics simulation

The use of electrolysis is an important method for generating industrial hydrogen by water splitting into hydrogen and oxygen. This research outlines how kinetic parameters and the reaction behaviours of complex chemical processes resulting in fundamental technologies ranging from monometallic surfaces (Ni and Pt) to heterometallic surfaces (NiO, Fe/Ni, Pt/Ni) in an alkaline environment of approximately 30% KOH at 300 K–550 K can be extracted using reactive molecular dynamics (RMD) approach. The analytical overview of the detailed hydrogen evolution response of a multifaceted chemical system from reactants to products through different intermediates is provided, in order to maximize the performance of the reactive processes to deliver the desired products and eliminate unnecessary side products. Here, we concentrate on demonstrating that the kinetics information and reaction mechanisms required to explain the reactions analytically from such RMD are realistic. It is then possible to use this analytical definition to integrate the right reaction chemistry from the atomistic description of ReaxFF into larger-scale simulations using continuum chemical dynamics and/or computational fluid dynamics approaches. By systematically altering the composition of the surface, the integration of the second metal into the monometallic surfaces by aligning the ratio can dramatically increase the progressive alkaline electrolytic hydrogen evolution reaction (EHER) activity, and the best activity outperforms other advanced analogues in this study, is delivered from Fe/Ni heterometallic surface with a Fe/Ni ratio of 50%. The findings indicate that it is efficient to incorporate bimetallic component active sites for elementary steps to promote alkaline electrolytic hydrogen evolution reaction.

Effective removal of nickel(II) and zinc(II) in mono-compound and binary systems from aqueous solutions by application of alginate-based materials

ABSTRACT In the present study, beads of alginate, alginate-biuret and alginate-urea, were synthesised for the removal of Ni(II) and Zn(II) metal ions from aqueous solution (in single and in the bimetallic component solution). The properties of the synthesised sorbents were investigated by pHpcz, ESEM-EDX and ESEM. The modelling of experimental data demonstrate that the PSORE equation fits well the kinetic profiles, while Langmuir and also Sips models correspond well to the results of sorption isotherms (heterogeneous surface). Also, the spontaneous of process and endothermic nature of sorption was demonstrated by thermodynamic study. The maximum sorption capacity of 3.22, 4.73 and 8.53 mmol g−1 was found for the beads of alginate, alginate-biuret and alginate-urea, respectively, in case of Ni(II) while it was 6.77, 6.97 and 7.14 mmol g−1 for alginate, alginate-biuret and alginate-urea, respectively, in case of Zn(II). It was found that at 0.3 mmol L−1 concentration, Zn(II) was selectively adsorbed while Ni(II) ions were concentrated/enriched in the solution in the case of alginate-urea, but alginate-biuret and alginate beads adsorbed almost the same amount of Ni(II) and Zn(II). In the bimetallic solution, the study of selectivity coefficients (KS) shows that the alginate-urea is a selective sorbent for Zn(II) and alginate-biuret for Ni(II) ions. Therefore, the two functionalised polysaccharides do not show the same harmony in front of the two-chemical species, thus, giving the possibility of their use as selective adsorbents in solutions containing these elements and can be used in applications of different interest.

Steric effect induces CO electroreduction to CH4 on Cu–Au alloys

The electrocatalytic reduction of carbon monoxide (CO) is an emerging direction with new catalyst structures, among which the bimetallic component catalysts feature both functional diversity and high-density of active sites.

Optically activated and interrogated plasmonic hydrogels for applications in wound healing.

We disclose the use of hybrid materials featuring Au/Ag core/shell nanorods in porous chitosan/polyvinyl alcohol scaffolds for applications in tissue engineering and wound healing. The combination of Au and Ag in a single construct provides synergistic opportunities for optical activation of functions as near infrared laser tissue bonding, and remote interrogation to return parameters of prognostic relevance in wound healing monitoring. In particular, the bimetallic component ensures optical tunability, enhanced shelf life and photothermal stability, serves as a reservoir of germicidal silver cations, and changes in near-infrared and visible color according to the environmental level of oxidative stress. At the same time, the polymeric blend is ideal to bind connective tissue upon photothermal activation, and to support fabrication processes that provide high porosity, such as electrospinning, thus putting all the premises for cellular repopulation and antimicrobial protection.

Enhanced interface strength in steel-nickel bimetallic component fabricated using wire arc additive manufacturing with interweaving deposition strategy

Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification. Here, wire arc additive manufacturing (WAAM) process was used to fabricate a steel-nickel structural component, whose average tensile strength of 634 MPa significantly exceeded that of feedstock materials (steel, 537 MPa and nickel, 455 MPa), which has not been reported previously. The as-fabricated sample exhibited hierarchically structural heterogeneity due to the interweaving deposition strategy. The improved mechanical response during tensile testing was due to the inter-locking microstructure forming a strong bond at the interface and solid solutions strengthening from the intermixing of the Fe and Ni increased the interface strength, beyond the sum of parts. The research offers a new route for producing high-quality steel-nickel dissimilar structures and widens the design opportunities of monolithic components, with site-specific properties, for specific structural or functional applications.

Combined laser-foundry manufacturing process of bimetals

Abstract. An analysis of existing methods and a new combined process of bimetallic fabrication are presented, according to which a special regular macro relief is made on the surface of its functional component by laser or mechanical treatment. The bimetallic component thus prepared is placed in sand form, the dimensions of the cavity of which correspond to its dimensions. A melt of the structural component of bimetal is fed to the surface of the functional component through a hole in the form of a special device with a defined flow rate. The process of manufacturing bimetal, the functional component of which was a nickel alloy, and structural – carbon steel St.3Mathematical modelling and computing determine the patterns of temperature distribution over the height of the projections of the macro relief when they are heated by the melt of the structural component of bimetal, depending on their geometrical parameters, thermophysical characteristics of the material, schemes and conditions of pouring. Metallographic studies have established the conditions under which metallurgical bonds are formed between bimetal components and their bond strength is ensured. It is proved that to insure high bond strength of bimetallic components and uniform distribution over the joint plane, it is necessary that the height of the macro relief and the step between them have the optimum value. In this case, the transverse dimensions of the projections (1x1) mm, the optimal dimensions of the projection height are 0.5 mm, the steps between them - 1.5 mm. The high efficiency of the new, innovative combined technology of bimetal manufacturing has been demonstrated.

Multiphysical characterization of FSW of aluminum electrical busbars with copper ends

This work investigates the benefits of having an aluminum (Al) busbar with welded copper (Cu) ends, and evaluates the force relaxation phenomena of a pre-loaded bolt joint on Cu versus Al, under cyclic thermal loading. The results show a force relaxation rate 50% lower in the Cu-bolted joint compared with the one in Al. The core of this research is the weldability analysis of Al-Cu butt joints made by friction stir welding (FSW). The materials are AA1050 H14/24 and Cu OF 04 with thickness of 6 mm. Temperature monitoring during the FSW cycle emphasize how heat generation depends mostly on local internal viscoplastic deformation. Tensile, bending, and microhardness tests were used to establish the mechanical properties. Optical microscope and scanning electron microscopy were used to characterize the microstructure. Joining mechanisms in the weld were investigated using energy-dispersive X-ray spectroscopy. The FSW resulted in 85% tensile strength efficiency compared to the Al base material, and 97% electrical conductivity efficiency compared to an ideal bimetallic component made of the same materials with no contact resistance. Electrical resistance of the FSW is 200 times lower than the electrical contact resistance between the Al-Cu materials while under high compressive force.

NiMoO4 nanosheet arrays anchored on carbon cloth as 3D open electrode for enzyme-free glucose sensing with improved electrocatalytic activity.

High electrical conductivity and more active sites exposure are crucial for improving the performance of electrocatalyst. Binary metal oxide nanoarray grown on conductive substrate offers a 3D self-supported electrode with a great promise in boosting its performance in enzyme-free glucose sensing. Here, NiMoO4 nanosheet arrays anchored on carbon cloth (NiMoO4 NSA/CC) was prepared via a simple hydrothermal synthesis and used as 3D self-supported electrode for enzyme-free glucose sensing. The morphology and composition of NiMoO4 nanosheet have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical results show that NiMoO4 NSA/CC exhibits remarkable high catalytic activity towards glucose oxidation, with a wide linear response ranging from 1μM to 0.9mM, a high sensitivity of 4.13mA/mM·cm2, and a low detection limit of 1μM (S/N = 3). The enhanced performance might be attributed to the merits of nanosheet arrays with large surface area, self-supported electrode with 3D open network, as well as bimetallic component with high conductivity. Furthermore, NiMoO4 NSA/CC also shows good selectivity and reliability for glucose detection in human serum. This work offers a new pathway for the construction of enzyme-free glucose sensor with high performance. Graphical abstract ᅟ.

Исследование напряженно-деформированного состояния и микроструктуры в зоне твердофазного соединения типа диск-вал из разноименных сплавов на основе никеля

Finite-element calculations have been carried out to determine the strain distribution formed during welding by a combination of pressure and shear in samples imitating the constituent parts of a "disk-shaft" type gas-turbine engine bimetallic component made of heterophase nickel-based superalloys. A physical simulation of this process has also been carried out. Computer simulations were accomplished using a two-dimensional axysymmetric model by means of DEFORM-2D package. EP975 and EK79 alloys with ultrafine-grained (UFG) structure were chosen as the materials for the disk and shaft, respectively. The initial strain rate was 10-5 s-1, and the welding temperature 1100 °C. The behavior of materials was described by experimental curves obtained for EP975 and EK79 alloys under a uniaxial compression at the welding temperature. According to known experimental data, shear strain near the welded surfaces improves the solid-phase bond quality and strength. Additionally, the solid-phase bond quality is enhanced by grain refinement, which leads to an increase of the area of grain boundaries and to accelerated grain boundary diffusion. The results of computer simulations have revealed that in order to increase the area of regions with large shear strain values one has to increase the displacement of the shaft relative to the disk. From physical simulation, it has been concluded that a high quality solid-phase bond formation is promoted by a small shear strain of EK79 and EP975 alloys with UFG structure under superplasticity conditions. Basing on the studies carried out, a possibility of obtaining a "disk-shaft" type part from EP975 and EK79 nickel alloys with a preliminarily processed UFG structure using solid-phase bonding by means of pressure and shear welding has been shown.

Preparation and characterization of porous Fe-Cu mixed oxides modified ZSM-5 coating/PSSF for continuous degradation of phenol wastewater

The porous Fe-Cu mixed oxides modified ZSM-5 coating/PSSF (paper-like sintered stainless steel fibers) catalysts were synthesized for the continuous degradation of phenol by means of catalytic wet peroxide oxidation. The catalysts were firstly characterized by XRD, N2 adsorption-desorption, SEM and EDS. Then, the activity of the catalysts was evaluated in a continuous reactor at the temperature of 80 °C under atmospheric pressure. The results indicated that phenol conversion of 100% and H2O2 conversion of 98% was obtained and the phenol can be oxidized into organic acids directly without toxic quinones by-products detected. The increase of Cu element can obviously increase the catalytic activity of FeCu-ZSM-5 coating/PSSF catalyst, and the doped of Cu element can effectively increase the stability of Fe active component. H2-TPR and XPS experiments were further carried out to investigate the interactions of the bimetallic component. Finally, catalytic reaction mechanisms of the phenol degradation over the catalysts were proposed. The excellent catalytic activity of the FeCu-ZSM-5 catalysts was resulted from synergistic effect of the Cu, Fe active component and high contacting efficiency of the ZSM-5 coating/PSSF support.