Alloy Research Articles

Study the Potential of Mineral Ceramics Based on Aluminium Oxide in Replacing Metal Alloys

Modern metal alloys used in the tooling industry often consist of expensive and rare metals, impacting affordability and sustainability. This research explores the potential of mineral ceramics, mainly composed of readily available aluminum oxide (Al2O3), as an alternative for high-performance engineering ceramics. This research highlights the advantages and disadvantages of mineral ceramics over various metal alloys. Further exploration could refine properties and expand industrial adoption, contributing to a more responsible and efficient materials landscape.

Microstructural refinement of an Al-Ce-Mg alloy via Shear Assisted Processing and Extrusion

Al-Ce alloys have attracted recent interest because of their high thermal stability due to the low solubility of Ce in the Al matrix. The Al11Ce3 eutectic phase gives excellent strain hardening behavior and moderate high-temperature strength in the as-cast state. However, its strengthening effect is limited by its coarse as-cast structure. Therefore, alternative manufacturing methods such as additive manufacturing or equal channel angular pressing have been applied to refine the Al11Ce3 phase to good effect. However, these techniques are both expensive and time-consuming. Therefore, this study aims to use Shear Assisted Processing and Extrusion (ShAPE), an emerging solid phase processing technique that is more easily scalable than the previously mentioned methods. ShAPE can produce useful cross-sections of an Al-8Ce-4Mg alloy while refining the Al11Ce3 phase to produce a higher strength material. It was found that a low temperature ShAPE process can improve the room temperature yield strength by ∼60 % compared to a binary Al-4Mg alloy. Additionally, the high-temperature yield strength of the Al-Ce alloys increased by 20 %, with a simultaneous 15 % improvement in ductility compared to the binary Al-Mg alloy. These results highlight the potential for ShAPE as a processing technique for Al-Ce alloys.

The Development of Uniform-Sized Pt-Based Binary Alloy Electrocatalysts for ORR in Polymer Electrolyte Fuel Cells

Developing a highly efficient and durable reduced platinum metal (PtM) alloy catalyst with high oxygen reduction reaction (ORR)activity for polymer electrolyte fuel cells (PEFCs) is of significant interest. In this study, platinum-iron (PtFe), platinum-nickel (PtNi), and platinum-cobalt (PtCo) alloys were prepared with an average diameter of ca. 3 nm, uniformly dispersed on a high surface area carbon. The ORR activity of the prepared PtM/C catalysts was investigated under both RDE and MEA conditions. The resulting PtM/C catalysts demonstrated improved I-V cell performance at low-current density (LCD) and high-current density (HCD) regions. These findings suggest that high ORR activity and enhanced durability can be achieved through the formation of uniform Pt skin with higher electrochemical surface area (ECSA).

Development of Novel Ternary Alloy of CSiSn for Low-Cost Next Generation Photovoltaics

The growing need for highly efficient solar cells calls for significant advancements in the development of a new material system to meet the needs of low-cost and low-cost production. Current multi-junction solar cell alternatives are more costly to produce. This research showcases the development and analysis of a novel ternary material system, The CSiSn (CST) alloy, which shows potential for creating low-cost material with high absorption in of solar spectrum. In this work, the following aspects regarding the CST material are investigated: 1) Material modeling using density functional theory, 2) electronic band structure estimations, 3) low-temperature material growth technique via Plasma Enhanced Chemical Vapor Deposition (PE-CVD) system; 4) advanced material and optical characterizations of CST alloys.

Effect of Annealing Time on Various PtNi/C Binary Alloy Catalysts for ORR in PEFCs

Polymer electrolyte fuel cells (PEFCs) are used in automotive power supplies due to their advantages of low environmental impact and high energy conversion efficiency. However, Pt used for electrocatalysts is expensive and its activity and durability are problematic. In this study, the PtNi/C catalysts were prepared with different annealing times and the oxygen reduction reaction activity was evaluated. The linear sweep voltammograms and current-voltage curves showed that the PtNi/C catalysts annealing time for 60 min performed better than the commercial catalyst. This would be attributed to the internal alloying of Ni and better electronic structure due to the longer annealing time.

Modified embedded-atom method interatomic potentials for the V-X (X= Cr, Fe) binary and CoCrFeNiTiV multinary alloys

Interatomic potentials based on the second nearest-neighbor modified embedded-atom method (2NN-MEAM) have been developed for Fe-V and Cr-V binary alloys. The structural, mechanical and thermodynamic properties of various stable and metastable phases in Fe-V and Cr-V binary systems were calculated by molecular dynamic (MD) simulation using the developed 2NN-MEAM potentials. A good consistency between the MD-calculated data and the experimental data or first-principles calculations was obtained. The potentials were further employed to predict several chemically complex intermetallic alloys (CCIAs) with stable B2 and L12 ordered structures in CoCrFeNiTiV system. Finally, this work pave the way to investigate the atomic scale physical metallurgy of V-containing and chemically complex intermetallic alloys and adjust their composition and microstructure to meet the specific requirements entailed in advanced applications.

A(CoFe)(S2)2/CoFe heterostructure constructed in S, N co-doped carbon nanotubes as an efficient oxygen electrocatalyst for zinc-air battery

Transition metal alloys can exhibit synergistic intermetallic effects to obtain high activities for oxygen reduction/evolution reactions (ORR/OER). However, due to the insufficient stability of active sites in alkaline electrolytes, conventional alloy catalysts still do not meet practical needs. Herein, by using polypyrrole tubes and cobalt-iron (CoFe) Prussian blue analogs as precursors, CoFe sulfides is in-situ formed on CoFe alloys to construct (CoFe)(S2)2/CoFe heterostructure in sulfur (S) and nitrogen (N) co-doped carbon nanotubes (CoFe@NCNTs-nS) via a low-temperature sulfidation strategy. The as-marked CoFe@NCNTs-12.5S exhibits a comparable ORR activity (half-wave potential of 0.901 V) to Pt/C (0.903 V) and a superior OER activity (overpotential of 272 mV at 10 mA cm−2) to RuO2 (299 mV). CoFe@NCNTs-12.5S also exhibits ultralow charge transfer resistances (ORR-6.36 Ω and OER-0.21 Ω) and an excellent potential difference of 0.617 V. The sulfidation-induced (CoFe)(S2)2/CoFe heterojunctions can accelerate interfacial charge transfer process. Tubular structure not only disperses the (CoFe)(S2)2/CoFe heterostructure, but also reduces the corrosion of active-sites to enhance catalysis stability. Zinc-air battery with CoFe@NCNTs-12.5S achieves a high specific capacity (718.1 mAh g−1), maintaining a voltage gap of 0.957 V after 400 h. This work reveals the potential of interface engineering for boosting ORR/OER activities of alloys via in-situ heterogenization.

Effect of Silicon Carbide Particulates on Mechanical Behavior of Al5052 Alloy Metal Matrix Composites for Mining Applications

In particular, the impact of Silicon Carbide (SiC) particles on the mechanical properties of stir-cast Al5052 alloy Metal Matrix Composites (MMCs) for rotor blade applications is examined in this work. The goal of integrating SiC particles is to improve mechanical characteristics including wear resistance, tensile strength, and hardness while preserving the ideal weight-tostrength ratio, which is essential for rotor blade performance. The Al5052 matrix was filled with SiC in a variety of compositions (0%, 2%, 4%, 6%, and 8% by weight), and the resultant composites underwent mechanical testing and microstructural examination. Due to the efficient load transfer and reinforcing processes, the results show a considerable improvement in tensile strength and hardness with the addition of SiC particles. Furthermore, microstructural analyses demonstrate a uniform dispersion of SiC in the matrix, which supports the improved performance attributes. Wear resistance of Al5052 alloy is greatly increased when Silicon Carbide (SiC) particles are added as reinforcement. This makes the composite material perfect for applications requiring great durability and longevity to survive hard mining conditions, such as wear plates, conveyor liners, and drill bits in mining machinery components.

A Combined First-Principles and Data-Driven Computational Framework to Analyze the Surface Structure, Composition, and Stability of Binary Alloy Catalysts

A Combined First-Principles and Data-Driven Computational Framework to Analyze the Surface Structure, Composition, and Stability of Binary Alloy Catalysts

Methods of Processing Dental Chromium-Cobalt Alloys for Production of Metal Frameworks Faced with Ceramics to Obtain the Best Mechanical Properties.

BACKGROUND Modern prosthetic technologies make it possible to fabricate prosthetic restorations without material loss and to make prosthetic restorations with complex geometric shapes in a relatively simple way. One such technology is selective laser melting (SLM), or additive manufacturing of metal materials, better known as 3D printing from metal or selective laser melting, but currently the most commonly used method is casting. The present study investigated use of dental chromium-cobalt alloys for prosthetic bridges and compared methods of processing dental chromium-cobalt alloys to obtain the best mechanical properties. MATERIAL AND METHODS We used dental chromium-cobalt alloy (SCHEFTNER GMBH) for laser melting StarbondCoSEeasy Powder with grain size of 10-30 µm and StarbondCoS alloy casting, made in accordance with the European standard EN ISO 22674. SLM-made specimens and induction melted alloy castings were prepared for the study. A centrifugal casting system with induction current melting of the metal alloy was used to produce the samples. The melting and casting process is automatic and limits changes in chemical composition. RESULTS The results show that none of the samples changed their chemical composition, while the samples made by SLM had better mechanical properties. CONCLUSIONS The SLM technique makes it possible to produce restorations faster and cheaper without any loss of quality compared to restorations made with the casting technique. Casting technology reduces mechanical properties, but still provides good mechanical properties.

PEPR DIADEM: Priority equipment and research program on the development of innovative materials using artificial intelligence

IntroductionThe quest to develop efficient, sustainable materials from non-critical, non-toxic resources is one of today's most formidable challenges in the current context of energy, transport, digital or healthcare transitions. In response, France launched the pioneering Priority Equipment and Research Program (PEPR) DIADEM in 2022. This innovative initiative, focused on DIscovery Acceleration for the Deployment of Emerging Materials (DIADEM), leverages Artificial Intelligence (AI) to accelerate the innovation chain from conception to realization, revolutionizing Materials Science sustainably. With a strategic emphasis on scientific synergy, PEPR DIADEM aims to expedite the discovery and development of novel materials essential for contemporary and future societal challenges. To achieve this, the program seeks to catalyze breakthroughs in areas ranging from energy efficiency to transportation, digitalization, and healthcare, covering a broad spectrum of materials from metallic alloys to functional nanostructures. Aligned with the Green Deal framework's ambitious targets, PEPR DIADEM addresses the urgent need for accelerated sustainable materials research. By utilizing cutting-edge technologies like rapid synthesis and characterization tools, automation, digital simulations, data management, AI, additive manufacturing, and thin film engineering, the program is set to significantly reshape the materials science landscape. As PEPR DIADEM embarks on its journey of innovation, it not only advances scientific knowledge but also holds the promise of addressing current global challenges and paving the way for a more sustainable and prosperous future.

Separation of Co(II), Mn(II), and Ni(II) by solvent extraction with Cyanex 272 and D2EHPA from the sulfuric acid leaching solution of spent lithium-ion batteries

Spent lithium-ion batteries contain valuable metals such as cobalt, lithium, manganese and nickel. Smelting reduction of spent LIBs at high temperature results in metallic alloys. Therefore, it is necessary to recover the valuable metal ions present in the sulfuric acid leaching solutions of the metallic alloys. In this work, solvent extraction experiments were performed to separate the three metal ions, Co(II), Mn(II) and Ni(II) present in the leaching solutions of the metallic alloys. Synthetic sulfate solutions were prepared and commercial organophosphorous extractants were employed. First, both Co(II) and Mn(II) were completely extracted in one stage by using 40% saponified 0.3 M Cyanex 272, leaving Ni(II) in the raffinate. The small amount of Ni(II) co-extracted into Cyanex 272 was removed by two stages of cross-current scrubbing using pure CoSO4 solution. The effect of pH and CoSO4 concentration of the scrubbing solution on the scrubbing of Ni(II) was investigated. The Co(II) and Mn(II) present in the scrubbed Cyanex 272 were completely stripped by 0.05 M H2SO4 solution. Batch simulation experiments for the three stage of counter-current extraction with 1 M D2EHPA verified that Mn(II) and Co(II) were completely separated by selective extraction of Mn(II) into D2EHPA, leaving Co(II) in the raffinate. By consecutive extraction with Cyanex 272 and D2EHPA, pure solutions of Co(II), Mn(II) and Ni(II) with purity higher than 99.9% can be recovered from the starting solutions. A process was proposed for the treatment of sulfuric acid leaching solutions of spent LIBs containing Co(II), Mn(II) and Ni(II) by solvent extraction.

The Influence of Alloy Composition on Microstructure and Performance of Mixed-Smelting Alloy and Weld Metal.

In the present work, the Q345B low-alloy steel with different contents and ER309L stainless steel were melted together to obtain new alloys. The aim was to design the composition of weld metal (Q345B low-alloy steel as the base material and ER309L welding wire as the filler material) and improve the corrosion resistance of the weld metal. During the welding process, the composition of the weld metal was controlled to match the new alloys by changing the welding heat input. A relationship curve between fusion ration and welding heat input was obtained. The research focused on analyzing the effect of mixed-smelting ratio between Q345B and ER309L and welding heat input on the microscopic structure and corrosion performance of the prepared samples. The results show that the melted alloys containing 20% to 30% Q345B consist of a ferrite (δ) phase and austenite (A) phase, the samples containing 45% to 50% Q345B consist of a martensite (M) phase and austenite (A) phase, and the sample containing 40% Q345B consists of a martensite (M) phase, ferrite (δ) phase, and austenite (A) phase. As the mixed-smelting ratio of Q345B/ER309L increased, the corrosion resistance of samples decreased gradually. For the weld metal, the fusion ration between Q345B base material and ER309L welding wire increases with the welding heat input. When the heat input changed from 0.645 kJ/mm to 2.860 kJ/mm, the composition of the weld metal was consistent with the melted alloys containing 20-45% Q345B. The microstructure and corrosion resistance of the weld metal could be designed by the melting means, which has important guiding significance for engineering applications.

Direct Laser‐Deposited Ni36.5Co36.5Cr18Al4.5Ti4.5 Multiprincipal Component Alloy

Multiprincipal component alloys (MPCAs) have been extensively investigated and shown promising properties. The MPCAs also provide a new class of metallic alloys for additive manufacturing. Herein, a precipitation‐strengthened Ni36.5Co36.5Cr18Al4.5Ti4.5 MPCA is fabricated by direct laser deposition (DLD). The overall formability of the bulk is very good, only a few cracks exist near the bottom of the substrate. The as‐deposited samples feature a unidirectional epitaxial columnar grain microstructure with a high volume fraction (about 44%) of dispersed nanoscale γ′ phases and demonstrate a <100>//build direction texture. The as‐deposited samples exhibit a high yield strength about 896 MPa, an ultimate tensile strength about 1173 MPa, and an elongation about 17% along the build direction. These results demonstrate the feasibility of DLD for producing high‐volume fraction precipitation‐strengthened MPCAs without defects.

Composition, Temperature, and Size Regulation of Refractive Index in Ternary Group-Ⅲ Nitride Alloys: a Bond Relaxation Investigation

Abstract The physical origins of composition-, temperature-, and size-motivated changes in refractive index in crystals have long been a puzzle. Combining the bond-order-length-strength theory, local bond average approach, and core-shell structural model, we investigated the refractive indexes in dependencies of composition, temperature, and size for the ternary wurtzite group-Ⅲ nitride alloys. The theoretical reproduction of the observations disclosed that (ⅰ) the doping of small atoms caused the contraction in bond length, the strengthening in bond energy, and the decrease of refractive index, whereas the doping of large atoms led to an elongation of bond length, a weakening of bond energy, and an increase of refractive index; (ⅱ) the refractive index is inversely proportional to the cohesive energy and the cube of the Debye temperature; and (ⅲ) with the gradual decrease in solid size, the coordination number lowers, the bond length contracts, the bond energy gains, the surface-to-volume ratio rises, and the refractive index decreases. The proposed formulation not only shows an in-depth comprehension of the physical essence of the stimuli impact on the refractive index but also is expected to be conducive to the exploitation, optimization, and operation of the new-type photonic, piezoelectric, and pyroelectric nanometer devices for the ternary wurtzite alloys.

Mechanical Properties and Microstructure of Laser Powder Bed Fusion‐Processed 18Ni300 Maraging Steel According to Direct Aging Treatment Conditions

The nonequilibrium microstructures produced by laser‐based additive manufacturing can enhance the mechanical properties of metallic alloys. However, the optimal post‐treatment conditions will change according to the initial microstructure induced by the manufacturing process employed. Therefore, this study investigates the optimal direct aging conditions for the post‐treatment of laser powder bed fusion‐processed 18Ni300 maraging steel by changing the aging temperature and time. The aging time required to achieve maximum tensile strength decreased as the aging temperature increased, and an increase in the aging temperature accelerated the evolution of nanoscale precipitates. The results indicate that the optimal direct aging conditions of 520 °C for 2 h achieved the largest tensile strength (≈2100 MPa) and precipitate area fraction. Notably, the reduced aging time at this temperature compared with that under conventional aging conditions (8 h at 460 °C or 490 °C) minimizes the thickening of the (Mo,Ti)‐rich segregation, which otherwise contributes to austenite reversion and strength reduction owing to overaging. Thus, the optimal direct aging conditions for additively manufactured maraging steel components are different from those for conventionally produced maraging steel components. This understanding of the microstructural changes induced by direct aging according to the initial non‐equilibrium state provides vital information for enhancing the performance of additively manufactured metallic alloys.

Realizing strength-ductility combination of Ni-12Mo-7Cr-2Nb based superalloy via nano-sized MC carbides at stacking faults and grain boundaries

Developing corrosion-resistant alloys with the outstanding strength-ductility combination at elevated temperatures are highly desirable for molten salt reactor (MSR) applications. In this study, by appropriate preaging process, the yield strength and elongation of one newly developed Ni-12Mo-7Cr-2Nb based superalloy at high temperatures respectively increase by ∼50 % and ∼100 % as compared with the solid-solution state. This preaged alloy exhibits the excellent strength and overcomes the intermediate temperature embrittlement problem as compared with other alloys. Microstructure observations indicate that the strengthening and ductility improvement are related to the formation of nano-sized MC carbides. After preaging process, the extrinsic stacking faults are formed along {111} close-packed planes and decorated with ultra-dense MC carbide particles, thus are called as stacking faults precipitates (SFPs). SFPs contribute to the precipitation strengthening by the complex interaction with dislocations. Surprisingly, the SFPs exhibits the better strengthening effect than the uniformly dispersed MC carbides with the same volume fraction and size. Furthermore, it was found that the “pseudo-continuous” intergranular MC carbide particles are beneficial to the high-temperature ductility, although the similar intergranular precipitates were widely regarded as harmful in other studies. Using crystal plasticity finite element method, it was proved that the strain concentration at the triple junctions would be obviously alleviated because the intergranular MC carbide particles can suppress grain boundary sliding. If tested at 750 °C, the intergranular MC carbide particles would trigger the particle-stimulated nucleation and lead to the local dynamic recrystallization at grain boundaries and crack tips. These small recrystallized grains can suppress crack propagation and bring about the improvement in ductility in the aged alloy.

Synthesis of complex concentrated silicide coatings via reactive melt-infiltration: Exploring interfacial phenomena between Si-B melt and MoNbTaW high-entropy alloy

High-entropy silicide (HES) coatings are a promising solution to the problem of poor oxidation resistance of metallic refractory alloys. However, their practical development is still in the early stages. For the first time, this study evaluates the feasibility of synthesizing complex concentrated silicide coatings using a reactive melt infiltration approach. For this purpose, a sessile drop experiment was carried out in which a binary eutectic silicon‑boron alloy (Si8B at.%) was subjected to contact heating with the MoNbTaW refractory high entropy alloy (RHEA) substrate at temperatures up to 1450 °C. After the high-temperature test, the solidified couple was characterized by X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, electron backscatter diffraction systems, and microhardness techniques. The coating had an average thickness of 75 μm and was composed of different layers, including a primary MSi2 layer, a transition MSi2 + M5Si3 silicide layer, and M5Si3 silicides (M = metal). Additionally, borosilicides and boride particles were dispersed throughout the layers. However, future research should prioritize refining process parameters to eliminate porosity and improve the integrity of the coating layer.

Extending the Pre-ordered Precursor Reduction strategy to L10 ternary alloys: the case of MnFePt

L10 nanostructured alloys continue to attract a great deal of attention due to their advanced physico-chemical properties arising from the peculiar arrangement of the atoms in the tetragonal unit cell. Efforts have been focused on synthesizing and optimizing L10 3d-5d binary alloys, with the incorporation of a third element to enhance the chemical order degree and/or modulate the physical properties. Among the family members, magnetic L10 MnFePt ternary alloys are of great relevance owing to the possibility to tune the magnetic properties to meet the requirements of many applications including data storage/processing, sensors, catalysis, and biomedicine. In this work, a direct, effective and sustainable strategy, called Pre-ordered Precursor Reduction (PPR), was exploited for the first time to synthesize highly-ordered L10 MnFePt ternary alloy nanoparticles by thermal decomposition in reductive atmosphere of MnxFe1-x(H2O)6PtCl6 crystal salts whose crystallographic structure resembles the specific atomic arrangement of the L10 phase. Despite the higher complexity with respect to the binary system, the peculiar atomic arrangement of the elements in the precursor crystalline salt allows a great control over the structural and magnetic properties. By modulating the process conditions and the initial chemical composition it is possible to finely tune the magnetic properties thus proving the high versatility and efficiency of the PPR approach to synthesize highly ordered L10 ternary alloys with controlled properties.

Monitoring of suspended matter in the Dnipro River within Zaporizhzhia city, the main trends of 2022

The article presents the results of monitoring observations on the temporal distribution of the qualitative and quantitative components of the Dnipro River suspended matter within Zaporizhzhia city. The research on the territory of this powerful industrial center of Ukraine with a developed metallurgical complex was carried out from 2015 up to 2019 and from the end of 2021 to the present time. The main task of the research was determining the distribution of iron and a group of heavy metals of anthropogenic origin in the composition of the river suspension, and identifying the connections of their concentrations and forms with the natural conditions of the region. Sedimentary matter from the water flows of Dnipro River within research area was sampled once per month using sedimentary traps developed by authors. The methods of electron microscopy (with microprobe analysis) and laser diffraction analysis were used to study the suspension granulometric and chemical composition in the Center for Shared Use of Scientific Equipment of the IGS NASU. SEM studies were carried using scanning electron microscope SEM JEOL-6490 LV (Jeol Ltd., Japan) with an energy dispersive spectrometer of the X-ray microanalysis system INCA Energy+ (Oxford Instruments plc., Great Britain). Particle size analysis was determined using the laser particle size analyzer Mastersizer 2000 with a Hydro 2000S wet dispersion module (Malvern Ins. Ltd, UK).The study results of the samples taken in the first year of hostilities in Ukraine revealed a number of features which were not observed in the previous series of studies. Those peculiarities are the following ones: reduction in the intensity of sedimentary matter accumulation; decrease of technogenic components in the suspension content (in particular, the amount of ferrous metals, changes in the ratio of condensed and dispersed iron particles of silt size, as well as the component composition of fragments of alloys of non-ferrous and ferrous metals). The obtained results may indicate the sensitivity of the component composition of the suspension to changes in the external environment in general, as well as the significant impact of the anthropogenic component on the distribution of iron in suspended matter.