Nanostructured Alloys Research Articles

Atomic Scale Cooperativity of Alloy Nanostructures for Efficient Nitrate Electroreduction to Ammonia in Neutral Media

AbstractElectrochemical nitrate reduction reaction (NO3RR) offers a route to balanced nitrogen cycle and sustainable ammonia production. However, unsatisfied performance in neutral media arising from competitive hydrogen evolution reaction and inefficient hydrogenation impede the further applications of NO3RR. Herein, the rational design of RuNi alloy nanostructures is reported. Benefited from the synergism effect between Ru and Ni, Ru20Ni80 alloy exhibits a high NH3 Faradaic efficiency of 98.02% at −0.35 V (vs reversible hydrogen electrode (RHE)) and a large NH3 yield rate of 27.88 mg mgcat−1 h−1 at −0.65 V (vs RHE). Importantly, the atomic scale cooperation between Ru and Ni active sites endows RuNi alloy a close‐to‐unity NH3 selectivity via HNO* pathway. Theoretical calculations have revealed that the interactions between Ru and Ni optimize the electronic structures of Ru20Ni80 alloy, where Ru sites with enhanced electroactivity improve the generation of active hydrogens and more electron‐rich Ni sites facilitate the reduction of nitrate. Accordingly, the adsorption strengths of key intermediates become stronger and the energy barriers of NO3RR are reduced to guarantee efficient NO3RR. Furthermore, a flow‐type reactor coupled with coprecipitation is established to achieve continuous NH3 generation and recovery as struvite.

Coexistence of Superconductivity and Magnetic Ordering in the In-Ag Alloy Under Nanoconfinement.

The impact of the interface phenomena on the properties of nanostructured materials is the focus of modern physics. We studied the magnetic properties of the nanostructured In-Ag alloy confined within a porous glass. The alloy composition was close to the eutectic point in the indium-rich range of the phase diagram. Temperature dependences of DC magnetization evidenced two superconducting transitions at 4.05 and 3.38 K. The magnetization isotherms demonstrated the superposition of two hysteresis loops with low and high critical fields below the second transition, a single hysteresis between the transitions and ferromagnetism with weak remanence in the normal state of the alloy. The shape of the loop seen below the second transition, which closes at a low magnetic field, corresponded to the intermediate state of the type-I superconductor. It was ascribed to strongly linked indium segregates. The loop observed below the first transition is referred to as type-II superconductivity. The secondary and tertiary magnetization branches measured at decreasing and increasing fields were shifted relative to each other, revealing the proximity of superconducting and ferromagnetic phases at the nanometer scale. This phenomenon was observed for the first time in the alloy, whose components were not magnetic in bulk. The sign of the shift shows the dominant role of the stray fields of ferromagnetic regions. Ferromagnetism was suggested to emerge at the interface between the In and AgIn2 segregates.

Additive manufacturing of multiscale NiFeMn multi-principal element alloys with tailored composition

Abstract Nanostructured multi-principal element alloys (MPEAs) have been explored as next-generation engineering materials due to unique mechanical and functional properties which have significant advantages over traditional dilute alloys. However, the practical applications of nanostructured MPEAs are still limited due to the lack of scalable processing approaches to prepare a large quantity of nanostructured MPEAs, as well as lack of an efficient pathway for high-throughput discovery of better functional nanostructured MPEAs within their vast compositional space. Here we tackle these challenges by presenting an integrated approach by combining direct-ink-writing-based additive manufacturing, solid-state sintering, and chemical dealloying to manufacture hierarchically porous MPEAs. The hierarchical structure is comprised of macro- and micro-scale pores introduced via extrusion printing and polymer decomposition during sintering, as well as nanoscale pores formed via chemical dealloying. The macro- and micro-scale pores allow efficient dealloying of a large mass of material as the diffusion length that the corroding medium must penetrate remains at the scale of the ligaments formed after sintering (∼10 μm), despite the large volume of the 3D-printed samples. In addition, this integrated approach enables versatile control of the alloy composition via precisely tuning the ratio of elemental powders in the starting ink, thus offering a pathway for high-throughput discovery of novel functional MPEAs. As a case study, multiscale macro/micro/nanoporous NiFeMn MPEAs with three different compositions were investigated as catalysts to reduce the overpotential of oxygen evolution reaction (OER), where NiFeMn-based electrocatalysts display composition-dependent performance such that the overpotential measured at a current of 0.5 A g−1 for OER increases in the order of Ni58Fe29Mn13 ⩽ Ni64Fe26Mn10 < Ni76Fe18Mn6. This introduced manufacturing process offers new opportunities for scalable fabrication and rapid screening of nanostructured multi-component complex alloys.

In Situ Solid-State Dewetting of Ag-Au-Pd Alloy: From Macro- to Nanoscale.

Metal alloy nanostructures represent a promising platform for next-generation nanophotonic devices, surpassing the limitations of pure metals by offering additional "buttons" for tailoring their optical properties by compositional variations. While alloyed nanoparticles hold great potential, their scalability and underexplored optical behavior still limit their application. Here, we establish a systematic approach to quantifying the unique optical behavior of the AgAuPd ternary system while providing a direct comparison with its pure constituent metals. Computationally, we analyze their electronic structure and uncover the transition of Pd d states to Pd/Ag hybridized s states in the bulk form, explaining the similar optical properties observed between Pd and AgAuPd. Experimentally, we fabricate pure metal and fully alloyed nanoparticles through solid-state dewetting, a scalable method. During the process, we trace the optical transition in the systems from the initial thin film stage to the final nanoparticle stage with in situ ellipsometry. We reveal the interplay between optical properties influenced by chemical interdiffusion and localized surface plasmon resonance arising from morphological changes with ex situ surface characterizations. Additionally, we analytically implement a metallic layer derived from the ternary system in a trilayer device, resulting in a single-time and irreversible color filter, to demonstrate an application encompassing a lithography-free and cost-effective route for nanophotonic devices.

Friction and Wear Resistance of Nanostructured TiNi Shape Memory Alloy

TiNi shape memory alloys with a superelastic effect are widely used in tribological interfaces requiring high wear resistance. One of the common approaches to reducing the wear of various metals is the application of severe plastic deformation (SPD), resulting in structural refinement and corresponding hardening. This paper investigates the tribological behaviour of a nanostructured Ti49.3Ni50.7 shape memory alloy produced using SPD. The friction and wear characteristics of the alloy at room temperature are compared in the coarse-grained, nanostructured, and nanostructured aged states. Through hardness measurement and transmission electron microscopy, it is shown that the transformation of a coarse-grained state into a nanostructured state increases wear resistance and hardness, reduces the coefficient of friction, and changes the friction mechanism. Formed nanoparticles during ageing in a nanostructured state further increase wear resistance.

Near-theoretical strength and deformation stabilization achieved via grain boundary segregation and nano-clustering of solutes

Grain boundary hardening and precipitation hardening are important mechanisms for enhancing the strength of metals. Here, we show that these two effects can be amplified simultaneously in nanocrystalline compositionally complex alloys (CCAs), leading to near-theoretical strength and large deformability. We develop a model nanograined (TiZrNbHf)98Ni2 alloy via thermodynamic design. The Ni solutes, which has a large negative mixing enthalpy and different electronegativity to Ti, Zr, Nb and Hf, not only produce Ni-enriched local chemical inhomogeneities in the nanograins, but also segregate to grain boundaries. The resultant alloy achieves a 2.5 GPa yield strength, together with work hardening capability and large homogeneous deformability to 65% compressive strain. The local chemical inhomogeneities impede dislocation propagation and encourage dislocation multiplication to promote strain hardening. Meanwhile, Ni segregates to grain boundaries and enhances cohesion, suppressing the grain growth and grain boundary cracking found while deforming the reference TiZrNbHf alloy. Our alloy design strategy thus opens an avenue, via solute decoration at grain boundaries combined with local chemical inhomogeneities inside the grains, towards ultrahigh strength and large plasticity in nanostructured alloys.

Plasmon‐Promoted Interatomic Hot Carriers Regulation Enhanced Electrocatalytic Nitrogen Reduction Reaction

AbstractUtilizing hot carriers for efficient plasmon‐mediated chemical reactions (PMCRs) to convert solar energy into secondary energy is one of the most feasible solutions to the global environmental and energy crisis. Finding a plasmonic heterogeneous nanostructure with a more efficient and reasonable hot carrier transport path without affecting the intrinsic plasmonic properties is still a major challenge that urgently needs to be solved in this field. Herein, the mechanism by which plasmon‐promoted interatomic hot electron redistribution on the surface of Au3Cu alloy nanoparticles promotes the electrocatalytic nitrogen reduction reaction (ENRR) is successfully clarified. The localized surface plasmon resonance (LSPR) effect can boost the transfer of plasmon hot electrons from Au atoms to Cu atoms, trigger the interatomic electron regulation of Au3Cu alloy nanoparticles, enhance the desorption of ammonia molecules, and increase the ammonia yield by approximately 93.9 %. This work provides an important reference for rationally designing and utilizing the LSPR effect to efficiently regulate the distribution and mechanism of plasmon hot carriers on the surface of heterogeneous alloy nanostructures.

Tuning the physical properties of ternary alloys (NiCuCo) for in vitro magnetic hyperthermia: experimental and theoretical investigation

Most of published research on magnetic hyperthermia focused on iron oxides, ferrites, and binary alloy nanostructures, while the ternary alloys attracted much limited interest. Herein, we prepared NiCuCo ternary alloy nanocomposites with variable compositions by mechanical alloying. Physical properties were fully characterized by XRD, Rietveld analysis, XPS, SEM/EDX, TEM, ZFC/FC and H-M loops. DFT calculations were used to confirm the experimental results in terms of structure and magnetism. The results showed that the fabricated nanoalloys are face centered cubic (FCC) with average core sizes of 9–40 nm and behave as superparamagnetic with saturation in the range 4.67–42.63 emu/g. Langevin fitting corroborated the superparamagnetic behavior, while law of approach to saturation (LAS) was used to calculate the magnetic anisotropy constants. Heating effciencies were performed under an alternating magnetic field (AMF, H0 = 170 Oe and f = 332.5 kHz), and specific absorption rate (SAR) values were determined. The highest magnetic saturation (Ms), heating potentials, and SAR values were attained for Ni35Cu30Co35 containing the lowest Cu but highest Ni and Co percentages, and the least for Ni15Cu70Co15. Importantly, the nanoalloys reached the required temperatures for magnetic hyperthermia (42 °C) in relatively short times. We also showed that heat dissipiation can be simply tuned by changing many parameters such as concentration, field amplitude, and frequency. Finally, cytotoxicity viability assays against two different breast cancer cell lines treated with Ni25Cu50Co25 nanoalloy in the presence and absence of AMF were investigated. No significant decrease in cancer cell viability was observed in the absence of AMF. When tested against tumorigenic KAIMRC2 breast cancer cells under AMF, the NiCuCo nanoalloy was found to be highly potent to the cells (~ 2-fold enhancement), killing almost all the cells in short times (20 min) and clinically-safe AC magnetic fields. These findings strongly suggest that the as-prepared ternary NiCuCo nanoalloys hold great promise for potential magnetically-triggered cancer hyperthermia.

Elucidating the effect of strain path-dependent crystallographic texture evolution on the electrochemical behavior of nanostructured AA2024 aluminum alloy

This research provides insight into the effect of strain path-dependent texture evolution on the electrochemical behavior of nanostructured AA2024 aluminum alloy in a phosphate buffer solution (pH = 8.3). To achieve this, AA2024 alloy sheets were processed using two methods: accumulative roll bonding (ARB) and cross accumulative roll bonding (CARB), i.e., rotating the sheets 90° around the normal direction (ND) axis between each cycle. The ARB-processed AA2024 alloy exhibited a pancake-shaped structure and included texture components of Copper {112}<111>, Brass {011}<211>, P {110}<221>, and S {123}<634>. Meanwhile, the CARB-processed AA2024 alloy had extremely fine and equiaxed nano-grains (< 100 nm) and texture components of S {123}<634>, Brass {011}<211>, Goss {011}<100>, Rotated Cube {001}<110>, and P {110}<221> after eight cycles. Electrochemical studies demonstrated an increase in corrosion current density due to high imposed strains in the ARB route, which in effect made the conditions of passive layer formation more difficult and lowered the corrosion resistance. Additionally, achieving a more uniform distribution of extremely fine grains and {011} orientation textures such as Brass {011}<211>, Goss {011}<100>, and P {110}<221> texture components in the CARB route, provided ideal conditions for forming oxide passive films with superior protection properties compared to ARB. These unique findings can contribute to the broader application of crystallographic-orientation-dependent electrochemical behavior of alloys in the field of corrosion management.

High creep resistance in amorphous/crystalline dual-phase nanostructured CoCrFeNiMn high entropy alloys

Amorphous/crystalline dual-phase metallic materials received great attention owing to their synergistic combination of strength and ductility. However, the mechanisms governing creep deformation in these dual-phase materials are largely elusive. In the present letter, the creep deformation of amorphous/nanocrystalline CoCrFeNiMn high-entropy alloy (HEA) films is investigated through nanoindentation creep testing. It is suggested that dual-phase HEAs exhibit reduced creep strain compared to their monophase counterparts, and even surpass the performance of coarse-grained variants. This behavior arises from diffusion processes within the amorphous phase and the capacity for nucleation/annihilate of dislocations at amorphous/nanocrystalline interfaces. Furthermore, it is proposed that the presence of glass shell significantly influences the creep behavior of dual-phase HEAs.

Low-temperature superplastic behavior of nanostructured Al-Zn-Mg-Cu alloy

The evolution of Al-Zn-Mg-Cu alloy microstructure during high pressure torsion at room temperature and subsequent low-temperature superplastic deformation is studied. The formation of a nanostructured state in Al-Zn-Mg-Cu alloy made it possible to implement a superplasticity (SP) effect at 170 °C and a strain rate of 5 × 10−4 s−1. The deformation relief of the gauge part of an Al-Zn-Mg-Cu alloy sample at the stage of steady-state SP flow is analyzed. Low-temperature superplastic deformation is stated to take place due to grain boundary sliding. High formability of nanostructured alloy under biaxial tension at a temperature of 170 °C is recorded.

Kinetic Monte Carlo modelling of nano-oxide precipitation and its associated stability under neutron irradiation for the Fe-Ti-Y-O system

While developing nuclear materials, predicting their behavior under long-term irradiation regimes spanning decades poses a significant challenge. We developed a novel Kinetic Monte Carlo (KMC) model to explore the precipitation behavior of Y-Ti-O oxides along grain boundaries within nanostructured ferritic alloys (NFA). This model also assessed the response of the oxides to neutron irradiation, even up simulated radiation damage levels in the desired long dpa range for reactor components. Our simulations investigated how temperature and grain boundary sinks influenced the oxide characteristics of a 12YWT-like alloy during heat treatments at 1023, 1123, and 1223 K. The oxide characteristics observed in our simulations were in good agreement with existing literature. Furthermore, the impact of grain boundaries on precipitation was found to be minimal. The resulting oxide configurations and positions were used in subsequent simulations that exposed them to simulated neutron irradiation to a total accumulated dose of 8 dpa at three temperatures: 673, 773, and 873 K, and at dose rates of 10−3, 10−4, and 10−5 dpa/s. This demonstrated the expected inverse relationship between oxide size and dose rate. In a long-term irradiation simulation at 873 K and 10−3 dpa/s was taken out to 66 dpa and found the oxides in the vicinity of the grain boundary were more susceptible to dissolution. Additionally, we conducted irradiation simulations of a 14YWT-like alloy to reproduce findings from neutron irradiation experiments. The larger oxides in the 14YWT-like alloy did not dissolve and displayed stability similar to the experimental results.

Ultrahigh hardness with exceptional wear resistance of novel cost-effective nanostructured Fe40Ni25Cr25Mo5Al5 high-entropy alloy through cyclic closed-die forging process

Industry applications of current high-entropy alloys (HEAs) are limited by their prohibitive costs. Here, we present a cost-effective and facile approach to producing nanostructured HEAs with lower cost and exceptional mechanical properties. In the present work, the key was to design a novel cost-effective Fe40Ni25Cr25Mo5Al5 high-entropy alloy with an ultrafine-grained (UFG) microstructure through cyclic closed-die forging (CCDF) at room temperature for up to six passes. The as-homogenized alloy exhibited a dual-phase structure, with minor [CrMoFe]-rich dendrites dispersed in a nearly homogenous face-centered cubic (FCC) matrix. Increasing CCDF passes resulted in achieving a more homogeneous nanograin, accumulation of dislocations, fragmentation of [CrMoFe]-rich dendrites, and efficient distribution within the matrix, which provided ideal conditions for the development of a nanostructured Fe40Ni25Cr25Mo5Al5 alloy with superior mechanical properties (hardness and wear resistance). The highest microhardness (∼ 843 HV) and the lowest wear rate (∼ (0.9 ± 0.1) × 10–5 mm3.N−1.m−1) were obtained in the Fe40Ni25Cr25Mo5Al5 alloy after six CCDF passes. It was suggested that the Rotated Cube {001}<110> texture component of the CCDF-processed alloy contributed positively to the improvement of wear resistance properties. These findings suggest that CCDF processing has the potential to achieve cost-effective nanostructured high-entropy alloys and implement them in engineering and structural applications.

The ferrite/perovskite interface and helium partition in nano-structured ferritic alloys from the first-principles

Nano-oxides are largely responsible for the excellent mechanical properties and irradiation tolerance of nano-structured ferritic alloys (NFAs) for nuclear reactor applications. In this work, the roles of perovskite YTiO3 and its interface in trapping helium in NFAs were investigated from the first-principles. Similarly as other two Y-Ti-oxide phases (Y2TiO5 and Y2Ti2O7), bulk YTiO3 can trap insoluble helium at its interstitial sites, but with a lower trapping ability that is only comparable to matrix vacancies. The ferrite/YTiO3 interface phase diagram was constructed based on the experimental orientation relationship and the calculated interface formation energy, and the lowest-energy interface structure was predicted as the ns-Ti or the stoichiometric. Helium always prefers to consume individual interfacial vacancies and interstitial sites to the extent possible, before forming higher-order helium-vacancy clusters at the interface. Similarly as Y2Ti2O7, YTiO3 preferably traps helium at its interface, followed by its bulk interior and the ferritic matrix. However, in view of all the bulk and interface results, perovskite YTiO3 cannot compete with pyrochlore Y2Ti2O7 in trapping helium in NFAs.

Plasmon-Promoted Interatomic Hot Carriers Regulation Enhanced Electrocatalytic Nitrogen Reduction Reaction.

Utilizing hot carriers for efficient plasmon-mediated chemical reactions (PMCRs) to convert solar energy into secondary energy is one of the most feasible solutions to the global environmental and energy crisis. Finding a plasmonic heterogeneous nanostructure with a more efficient and reasonable hot carrier transport path without affecting the intrinsic plasmonic properties is still a major challenge that urgently needs to be solved in this field. Herein, the mechanism by which plasmon-promoted interatomic hot electron redistribution on the surface of Au3Cu alloy nanoparticles promotes the electrocatalytic nitrogen reduction reaction (ENRR) is successfully clarified. The localized surface plasmon resonance (LSPR) effect can boost the transfer of plasmon hot electrons from Au atoms to Cu atoms, trigger the interatomic electron regulation of Au3Cu alloy nanoparticles, enhance the desorption of ammonia molecules, and increase the ammonia yield by approximately 93.9 %. This work provides an important reference for rationally designing and utilizing the LSPR effect to efficiently regulate the distribution and mechanism of plasmon hot carriers on the surface of heterogeneous alloy nanostructures.

Morphology Variation of Ternary PdCuSn Nanocrystalline Assemblies and Their Electrocatalytic Oxidation of Alcohols.

Metal alloys not only increase the composition and spatial distribution of elements but also provide the opportunity to adjust their physicochemical properties. Recently, multimetallic alloy nanocatalysts have attracted great attention in energy applications and the chemical industry. This work presents the production of three ternary PdCuSn nanocrystalline assemblies with similar compositions via a one-step hydrothermal method. The shape variation of assembly units from nanosheets and nanowires to nanoparticles were realized by adjusting the percentage of Sn in metal precursors. Experimental data show that PdCuSn nanowire networks showed the best catalytic activity by virtue of their optimized morphological characteristics and microscopic electronic structure. With electrooxidation of methanol, ethanol, ethylene glycol, and glycerol at 30 °C, PdCuSn nanowire networks demonstrated catalytic activity of 1129, 2111, 2540, and 1445 mA mg-1, respectively. The catalytic activity for alcohol oxidation is attributed to the production of the electronic structure and morphology features that are most suitable. This is achieved by introducing the proper quantities of Cu and Sn components in the first stage of synthesis. This study would help with the construction of high-efficiency nanostructured alloy catalysts by regulating the electronic structure and morphology.

Alloy Reconstruction in Pyrolytic Bowknot-like Heteronuclear CoFe Clusters for Electrocatalytic Application.

The construction of doped molecular clusters is an intriguing way to perform bimetallic doping for electrocatalysts. However, efficiently harnessing the benefits of a doping strategy and alloy engineering to create a nanostructure for electrocatalytic application at the molecular level has consistently posed a challenge. Here we propose an in situ reconstruction strategy aimed at producing an alloy nanostructure through a pyrolysis process, originating from bowknot-like heterometallic clusters. The Schiff base, denoted as ligand L1 (o-vanillin ethylenediamine), was introduced as a precursor to coordinate Fe and Co metals, thereby yielding a heteronuclear metal cluster [(FeCo)(L1)2O]CH3CN. Subsequently, a comprehensive investigation of the in situ reconstruction process [(FeCo)(L1)2O](CH3CN) → [(FeCo)(L1)2O] → [M-O-M/M-O] [CH3+/CH3O+/H2C═N/C2H5+/C4H4+] → [FeCo/Fe3O4/Fe2O3/Co3O4][carbon layer] led to the formation of MOx/CoFe@NC-700 during the pyrolysis. This process reveals that the metals Fe and Co in the clusters undergo partly in situ evolution into FeCo alloys, resulting in the successful preparation of MOx/CoFe@NC (M = Fe, Co) nanomaterials that leverage the advantages of both doping strategies and alloy engineering. The synergistic interaction between alloy particles and metal oxides establishes active sites that contribute to the excellent oxygen evolution (OER) and hydrogen evolution (HER) catalytic behaviors. Notably, these materials exhibit outstanding OER and HER properties under alkaline conditions, with overpotentials of 191 and 88 mV for OER and HER, respectively, at 10 mA cm-2. Investigation of the in situ conversion of Schiff base bimetal clusters into alloy materials through pyrolysis offers a novel strategy for advancing electrocatalytic applications.

Thermal stability of 3D interface Cu/Nb nanolaminates

Nanocrystalline alloys are promising structural materials yet lack thermal stability in many cases. Recent work shows that interface structure has an outsize effect on the thermal behavior of nanostructured alloys. This work focuses on the role of controlled heterophase interface structure in the thermal evolution of model Cu/Nb nanolaminates. We introduce 3D interfaces containing nanoscale heterogeneities in all spatial dimensions between Cu and Nb, forming 3D Cu/Nb. TEM, nanoindentation, and DSC are used in tandem to establish thermal stability and to identify shifts in microstructure as a function of static annealing temperature. 3D interfaces are shown to survive annealing to 300 °C for 1 hr., while 3D Cu/Nb microstructure evolves to form low-density and voided regions correlating to the onset of layer pinch-off between 500 and 600 °C annealing temperatures. A diffusivity- and vacancy energetics-based mechanism is developed to explain void formation driven by 3D interface degradation at elevated temperature.

Thermo-kinetic insights into deformation mechanism in the phase-transforming nanostructured Fe alloy

Solid-state phase transformations (SSPTs) being the most widely versatile routes to tailor microstructures are less utilized in the design of nanostructured (NS) alloys, resulting in a lack of understanding of the significance of SSPTs in tuning mechanical properties. Here, we combine nanostructuring with reverse austenite transformation to make a phase-transforming NS Fe alloy consisting of ultrafine ferrite and austenite grains. By comparison with the coarse-grained (CG) counterpart, the NS sample exhibits high strengths (i.e., the yield and the ultimate tensile strengths are 816 and 1170 MPa, respectively), good ductility with a uniform elongation of 53 %, and superior strain hardening capacity, under multiple strengthening mechanisms and the activation of transformation induced plasticity. Regarding the mechanism in forming the NS sample, grain refinement is revealed to markedly affect the austenite formation kinetics by generating sluggish growth behavior accompanied by sufficient solute partitioning. Then, we clarify the difference in mechanical responses of the phase-transforming NS and CG samples using a physically based microstructures-properties model. Further based on the thermo-kinetic theory of generalized stability, we show that the simultaneous increase of strength and ductility in the NS sample relative to the CG sample is originated from the deformation physics with higher driving force and higher generalized stability. From the thermo-kinetic perspective, our work demonstrates that the SSPTs hold substantial promise in optimizing the microstructures and the mechanical properties of NS Fe alloys and are expected to find wide application in the development of other NS materials.

Regulating of wear properties through microstructure engineering in novel cost-effective Fe30Ni25Cr25Mo10Al10 high-entropy alloy processed by cyclic closed-die forging

This study presents a novel cost-effective Fe30Ni25Cr25Mo10Al10 high-entropy alloy with a dual-phase microstructure that was processed using cyclic closed-die forging (CCDF) at room temperature for a maximum of six passes. The as-homogenized alloy exhibited [CrMoFe]-rich dendrites with dual-size morphology dispersed in an almost uniform face-centered cubic (FCC) matrix. It was found that as the number of CCDF passes increased, leading to a more homogenous nanograin, there was an accumulation of dislocations, fragmentation of [CrMoFe]-rich dendrites, and enhanced distribution within the matrix. These conditions were conducive to the creation of a nanostructured Fe30Ni25Cr25Mo10Al10 alloy with superior mechanical properties. Texture analysis indicated that the prominent texture components for the Fe30Ni25Cr25Mo10Al10 alloy after six passes were Rotated Cube {001}<110>, S {123}<634>, and Dillamore {4 4 11}<11 11 8>. After the sixth CCDF pass, the Fe30Ni25Cr25Mo10Al10 alloy exhibited the highest microhardness (∼ 974 HV) and the lowest wear rate (∼ (0.8 ± 0.1) × 10–5 mm3.N−1.m−1). Additionally, it was proposed that the development of the Rotated Cube {001}<110> texture component contributed positively to enhancing wear resistance in the cost-effective high-entropy alloys. Considering the obtained results, it is reasonable to propose that CCDF processing is significant potential for the advancement of cost-effective nanostructured high-entropy alloys for industrial applications.