Core–shell structured high entropy oxide (HEO)–high entropy alloy (HEA) nanoparticles were successfully synthesized via a one-step ultrasonic spray pyrolysis (USP) process at 800 °C under a reducing hydrogen atmosphere. X-ray diffraction (XRD) analysis confirmed the coexistence of a rock salt–type HEO phase and a metallic FCC HEA phase. SEM observations revealed uniformly spherical particles with an average diameter of approximately 224 nm, consistent with the droplet-templating mechanism of USP. Advanced TEM analyses, including HRTEM, SAED, and STEM-EDS mapping, demonstrated a well-defined inverted core–shell particle structure, where the multicationic HEO phase is concentrated in the core while the HEA phase forms the outer shell. Unlike conventional oxide-shell/metal-core systems, this study presents a reversed configuration achieved in a single processing step without post-treatment. The results highlight the capability of USP to simultaneously control phase formation and nanoscale architecture in complex multicomponent systems, providing a promising platform for future catalytic and energy-related applications.

The integration of solar energy harvesting with electrochemical storage represents a promising strategy for next-generation microsystems. Here, we report a flexible asymmetric photo-microsupercapacitor (photo-MSC) based on pseudobrookite-type iron titanate (FeTi2O5) and V2CTx MXene electrodes fabricated on PET substrates. Iron titanate was synthesized from ilmenite via a sustainable route with a potential acid recovery system, yielding defect-rich nanopowder with a direct band gap of ∼2.31 eV and sub-bandgap states that enhance visible-light absorption. The asymmetric configuration leverages complementary charge storage mechanisms using diffusion-controlled pseudocapacitance in iron titanate and fast surface-capacitive behavior in MXene, delivering an areal capacitance of 78.99-361.67 mF cm-2. Under simulated solar illumination, capacitance increases by 45.8% at 50 mV s-1, with an energy density rising from 64.36 to 93.93 µWh cm-2 and power density from 5.80 to 8.45 mW cm-2. This photo-enhancement originates from efficient photogenerated carrier separation at the iron titanate/MXene heterojunction, confirmed by reduced charge-transfer resistance and improved carrier dynamics under illumination. The device further demonstrates excellent mechanical flexibility (∼92% capacitance retention at 180° bending) and practical energy delivery capability. This work establishes pseudobrookite iron titanate as a sustainable photoactive electrode material for integrated solar energy storage microsystems.

The Fe2AlB2 MAB phase features a nanolaminated structure and is notable for its near-room temperature magnetocaloric effect. Fe2AlB2 has promising properties but is usually synthesized from costly pure elements. Using cheaper metal oxides is largely unexplored, offering a new route. This work synthesizes Fe2AlB2 by combining self-propagating high-temperature synthesis (SHS) and vacuum arc melting (VAM). Fe2AlB2 and FeB phases were synthesized by SHS, an energy-efficient method. Before SHS, thermochemical modelling determined the starting molar amounts of the raw materials and predicted reaction propagation. To increase Fe2AlB2 concentration, two samples were prepared by adding 50 % and 100 % more aluminium (Al) than required, using the VAM technique. Samples were characterized by elemental, phase, microstructural analyses, and nanoindentation. Fe2AlB2 formed in both samples, with phase fractions of 47 wt% and 61 wt% for 50 % and 100 % Al addition, respectively, indicating that increased Al promotes Fe2AlB2 formation. Nanoindentation results for the Fe2AlB2 phase in the 100 % Al addition sample-hardness of 1249 +/- 23 Vickers (12.25 +/- 0.22 GPa) and Young's modulus of 284 +/- 17 GPa-were consistent with literature. This work provides a promising approach for the low-cost synthesis of Fe2AlB2.

Mo-boride and W-boride powders were produced from native boron oxide, magnesium, and related metal oxide starting materials by mechanochemical synthesis (MCS) followed by an purification treatment. The reaction formation mechanisms and the products were predicted with the FactSageTM thermochemical simulation program. Different conditions were tested to determine the optimum synthesis parameters. MCS was conducted at stoichiometric ratios and different milling durations, using excess reactant amounts over the determined optimum time. After MCS, unwanted phases were removed by HCl acid leaching. Detailed phase analyses of the final powders were obtained by X-ray diffractometer (XRD), whereas detailed microstructure characterization was conducted by scanning electron microscope/energy dispersion spectrometer (SEM/EDS), transmission electron microscope (TEM) and particle size analyzer. Among the utilized parameters, the ideal composition chosen for Mo boride synthesis was 6 h milled and leached MoO3-100 wt% B2O3-50 wt% Mg (1.41 mu m), including alpha-MoB, beta-MoB, MoB2, Mo2B, Mo2B5, and Mo phases. For the synthesis of W boride, the proper composition was found as WO3-100 wt% B2O3-50 wt% Mg (0.37 mu m) containing W2B5, WB, beta-WB, WB4, W2B, and W phases after milling for 20 h and leaching. Besides, as a result of the oxidation resistance measurements at 700 and 800 degrees C, phases belonging to MoO2 and WO2 were found along with boride phases.

CO 2 levels in the atmosphere are increasing as a result of human activities such as industrial activities, fossil fuel usage, and deforestation. The CO 2 methanation reaction, which converts CO 2 into methane, may play a crucial role in addressing this issue. Like most commercial syntheses, the CO 2 methanation process requires a catalyst. Spinel catalysts, particularly magnesium aluminate (MgAl 2 O 4 ), have gained attention for their potential in CO 2 methanation. In this study, MgAl 2 O 4 nanoparticles were synthesized using a sol–gel method with a molar ratio of Mg:Al = 1:2, and calcined at temperatures ranging from 700 to 900 °C. The structural properties of the nanoparticles were characterized using differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, X-ray diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The results showed that the particles had nearly spherical morphology, with agglomeration occurring at higher temperatures. The surface area decreased with increasing calcination temperature, from 188 m²/g at 700 °C to 94 m²/g at 900 °C. NiCo-MgAl 2 O 4 catalysts were prepared by impregnation and characterized by CO 2 temperature-programmed desorption and hydrogen temperature-programmed reduction. Catalytic performance tests revealed that the NiCo-MgAl 2 O 4 catalyst calcined at 800 °C achieved the highest CO 2 conversion (~85%) and methane selectivity. Spent catalyst analysis showed that carbon deposition negatively affected catalyst performance over time. This study emphasizes the role of strong basic sites in CO 2 activation and methane formation, suggesting future improvements in catalyst stability. Graphical Abstract

This study investigates an innovative method for producing TiO2 from ilmenite ore through selective thermal decomposition and leaching. The focus lies on understanding the impact of co-existing sulfates on the decomposition temperature of TiOSO4. Insights into the decomposition mechanisms and parameters governing selective leaching efficiency are also presented. Ilmenite concentrate was digested with concentrated sulfuric acid, yielding titanium and iron sulfates. The digested cake was then calcined at different temperatures to induce thermal decomposition. Thermodynamic calculations were employed to model the decomposition reactions and investigate the influence of iron sulfates on TiOSO4 decomposition. Both thermodynamic evaluation and experimental results demonstrate that co-existing iron sulfates play a catalytic role in lowering the decomposition temperature of TiOSO4 from approximately 700 degrees C to below 500 degrees C, facilitating its conversion to TiO2. The calcined powder underwent selective leaching, first with water to remove soluble sulfates, followed by dilute acid to obtain a TiO2 precipitate. The precipitate was analyzed by different techniques. The XRD analysis confirmed the successful conversion of TiOSO4 to Anatase TiO2 during calcination and leaching. The SEM images show that the Anatase TiO2 powder displays a near-spherical morphology, with a particle size ranging from 50 to 200 nm. FTIR, DTA, and DTG analyses supported the thermodynamic calculations and XRD results, offering insights into the phase transformations during thermal decomposition and leaching. The thermodynamic evaluation and experimental results demonstrate that co-existing iron sulfates play a catalytic role in lowering the decomposition temperature of TiOSO4. By using the proposed method, anatase powder was successfully produced with minor impurities of iron, SiO2, and other metal oxides.

This study reports the synthesis of AlxCoCrFeNiMn (0.5 ≤ x ≤ 3) alloys via fast, cost and energy-efficient aluminothermic self-propagating high-temperature synthesis (SHS) method. Starting oxides (Co3O4, Cr2O3, Fe2O3, NiO, MnO2, and Al2O3) and reducing agent aluminum (Al) amounts were calculated via thermochemical simulations extensively (FactSage™) together with the adiabatic temperature and gaseous phase compositions. The characterization results demonstrated that AlxCoCrFeNiMn (0.5 ≤ x ≤ 3) master alloys can be successfully synthesized via thermochemical modeling-assisted SHS method with a substantial composition control by using the optimum amount of Al2O3 as a heat suppressant. It was found that when the heat suppressant was higher, adiabatic temperature decreases extensively and large amount of spinel MnAl2O4 can form and remain unreacted which results in lower Mn in alloy. Conversely, most of the Mn is lost to evaporation when the heat suppressant is not used. Under optimum synthesis conditions, as Al content increases, the phase structure of the CoCrFeNiMn alloy transforms to BCC (A2, B2) from FCC (A1). The hardness increased substantially above x > 1 in the AlxCoCrFeNiMn system to the level of 668 HV. Ordered BCC-B2 content is responsible for the hardness increase as well as the reduction in saturation magnetization value (23 emu/g, 147.2 kA/m) for the Al1.5CoCrFeNiMn alloy (6.40 g/cm3). The highest saturation magnetization was found to be 83.7 emu/g (552.4 kA/m) with an observed density of 6.63 g/cm3 and moderate Hc = 43 Oe (3421 A/m) for the AlCoCrFeNiMn alloy. This study shows that Mn containing soft magnetic AlxCoCrFeNiMn (0.5 ≤ x ≤ 3) high-entropy alloys can be synthesized via thermochemical simulation coupled SHS, cost and time efficient method that can exhibit properties for future next-generation low density requiring applications. The removal of Cr from this system was found to be necessary to further elevate the soft magnetic properties and decrease the overall cost and density because it tends to segregate near the grain boundaries.

Prior investigations have demonstrated enhanced mechanical properties, such as hardness and wear resistance, through high-entropy alloy designs that contain refractory metals. We propose the WMoNbVCr x alloy phase space as a single-phase BCC-structured, hard, and refractory high-entropy alloy for the first time. The WMoNbVCr x alloy (x = 0, 0.25, 0.5, 0.75, and 1) system is investigated computationally through CALPHAD and DFT for the equimolar and non-equimolar compositional phase spaces and synthesized through vacuum arc melting. The DFT calculations demonstrated the excellence of specific non-equimolar compositional spaces. It was found that stoichiometries rich in W and poor in V are exceptionally hard, while those rich in V and poor in W demonstrate unprecedented toughness, as determined by the ductility descriptor (Pugh 's Ratio). The computational analysis shows the significance of microstructures that contain both (W-rich and W-poor) solid solution, where a synergy between hardness and toughness is created. Our experimental synthesis using vacuum arc melting demonstrated the possibility of successfully producing these alloys with W-rich (dendritic) and Wpoor (interdendritic) solid solution regions, starting from elemental powders. The introduction of chromium (Cr) resulted in enhanced microhardness and wear resistance. The peak microhardness was attained when 0.5 moles of Cr were added, reaching 7.03 +/- 0.24 GPa, accompanied by the least wear volume loss. The produced alloys were found to align with the computationally predicted-designed alloys in terms of the hardness and Young 's modulus trends that they follow. This comprehensive investigation underscores the synergistic application of CALPHAD and DFT techniques in the tailored design of novel high-entropy alloys, explaining their synthesis, structural correspondence, and the pivotal role of Cr in enhancing the mechanical properties of these alloys.

Rare-earth borides have become very popular in recent decades with high mechanical strength, melting point, good corrosion, wear, and magnetic behavior. However, the production of these borides is very challenging and unique. The production of ErB4 and NdB4 nanopowders via mechanochemical synthesis (MCS) is reported in this study first time in the literature. Er2O3 or Nd2O3, B2O3, and Mg initial powders are mechanically alloyed for different milling times to optimize the process. Rare-earth borides with MgO phases are synthesized, then MgO is removed with HCl acid. The nanostructured rare-earth tetraboride powders are analyzed using X-ray diffraction (XRD). Based on the XRD, ErB4 powders are produced successfully at the end of the 5 h milling. However, the NdB4 phase does not occur as the stoichiometric ratio, so the B2O3 amount is decreased to nearly 35 wt%. When the amount of B2O3 is decreased to 20 wt%, NdB4 and NdB6 phases are 50:50 according to the Rietveld analysis. However, a homogenous NdB4 phase is obtained with 30 wt% loss of B2O3. The average particle sizes of ErB4 and NdB4 powders are nearly 100.4 and 85.6 nm, respectively. The rare-earth tetraborides exhibit antiferromagnetic-to-paramagnetic-like phase transitions at 18 and 8.53 K, respectively.

In the current work, the thermodynamic properties of equiatomic and non-equiatomic Ni-Ti were estimated using Factsage Software for the “self-propagating high temperature synthesis (SHS) method. To calculate behind the pure substance model, the sublattice model was used. For the various ratios of the nickel in the B2 ordered phase and second intermetallics, the values of adiabatic temperature, Cp, Gibbs free energy, enthalpy of formation, products, and liquid-solid ratio were computed (Ni3Ti, Ti2Ni). These proporties play a crucial role in understanding the nature of propagating behavior since they affect the final product’s micro/macrostructure, mechanical characteristics, and stable or metastable phases. The results were compared with the literature. It was also discussed why the existing studies could not reach the theoretical adiabatic temperature and the effect of the ignition W wire on the sample was investigated with the experimental study.

This study represents an initial effort to produce NiTiFe shape memory alloys via the self-propagating high-temperature synthesis (SHS) process. The synthesis successfully yielded Ni 45 Ti 50 Fe 5 and Ni 40 Ti 50 Fe 10 alloys from elemental Ni, Ti, and Fe powders at three distinct preheating temperatures (240, 330, 420 °C). To support empirical findings, thermodynamic analysis using Factsage Thermodynamic Software was employed to correlate reaction propagation behavior with chemical composition. The calculation showed that the addition of 5 at.% Fe to the B2 phase did not hinder reaction self-propagation. This conclusion was supported with the ∆H f /Cp ratio and transient liquid ratio, computed using the sub-lattice model, which closely resembled that of NiTi. Whereas 10 at.% Fe that synthesized at preheating temperature of 240 °C exhibits struggle, thus an increase in triggering time causes an effect on crystallite size and a decrease in porosity. Empirical results confirmed these findings, albeit influenced by ignition times. An increase in the liquid ratio due to the adiabatic temperature rise can also result in a reduction of NiTi content when the Fe ratio is increased, consequently diminishing the driving force for the reaction. In the sample containing – 5% Fe, the main phase is B2, and the R martensitic phase is also present. Ms is determined to be – 38.7 °C. SEM analyses revealed the presence of Ti 2 Ni and Ti 2 Ni 3 phases in the upper and lower regions, while the distribution in the middle section is more homogeneous. No martensitic transformation was observed in 10% Fe. Additionally, nanocrystalline regions were detected within the samples by transmission electron microscopy, contributing to a nuanced understanding of their structural properties. Graphic abstract

GaN is a technologically indispensable material for various optoelectronic properties, mainly due to the dopant-induced or native atomic-scale point defects that can create single photon emitters, a range of luminescence bands, and n- or p-type conductivities. Among the various dopants, chromium and manganese-induced defects have been of particular interest over the past few years, because some of them contribute to our present-day light-emitting diode (LED) and spintronic technologies. However, the nature of such atomistic centers in Cr and Mn-doped GaN is yet to be understood. A comprehensive defect thermodynamic analysis of Cr- and Mn-induced defects is essential for their engineering in GaN crystals because by mapping out the defect stabilities as a function of crystal growth parameters, we can maximize the concentration of the target point defects. We therefore investigate chromium and manganese-induced defects in GaN with ab initio methods using the highly accurate exchange-correlation hybrid functionals, and the phase transformations upon excess incorporation of these dopants using the CALPHAD method. We also investigate the impact of oxygen codoping that can be unintentionally incorporated during crystal growth. Our analysis sheds light on the atomistic cause of the unintentional n-type conductivity in GaN, being O-N-related. In the case of Cr doping, the formation of Cr-Ga defects is the most dominant, with an E+/0 charge transition at E-VBM + 2.19 eV. Increasing nitrogen partial pressure tends to enhance the concentration of Cr-Ga. However, in the case of doping with Mn, several different Mn-related centers can form depending on the growth conditions, with Mn-Ga being the most dominant. Mn-Ga possesses the E2+/+, E+/0, and E0/- charge transitions at 0.56, 1.04, and 2.10 eV above the VBM. The incorporation of oxygen tends to cause the formation of the Mn-Ga-V-Ga center, which explains a series of prior experimental observations in Mn-doped GaN. We provide a powerful tool for point defect engineering in wide band gap binary semiconductors that can be readily used to design optimal crystal growth protocols.

The optical centers in AlN can frequently exist in various charge states and can be accompanied by many coexisting defect species, creating a complex environment where mutual interactions are inevitable. Therefore, it is an immediate quest to design AlN crystal growth protocols that can target a specific optical center of interest and tune its concentration while preventing the formation of other unwanted point defects. Here, we provide a powerful workflow for point defect engineering in wide band gap, binary semiconductors that can be readily used to design optimal crystal growth protocols through combining CALPHAD-based phase analysis, and ab initio defect calculations. We investigate technologically relevant chromium- and manganese-induced optical centers in AlN, followed by studying the impact of oxygen that can be unintentionally incorporated during crystal growth. We present the dominant defects in all three cases as a function of process parameters along with the optical signatures. In the case of both Cr and Mn doping, the CrAl and MnAl defects are most likely, and increasing nitrogen partial pressure tends to enhance their concentration. We show that it is possible to use nitrogen fugacity as a tool for tuning the intensity of optical signatures. We calculate the CrAl charge transition levels with respect to the valence-band maximum at 2.60 eV (E+/-), 3.83 eV (E0/-), and 5.41 eV (E-/2-) and electron and hole capture transitions with luminescence bands centered at 2.82, 1.91, and 3.15 eV. Unlike the Cr doping, Mn aggregation is unlikely, and the MnAl-VN is the most abundant defect after MnAl under most synthesis conditions. Oxygen tends to form complexes with VAl, and ON-VAl is a prominent defect following ON, with near-UV emission bands at 3.17, 3.26, and 3.81 eV. Our results agree with the available experimental optical signatures of Cr-, Mn-, and O-related centers and provide pathways on how to tune the luminous intensity of these centers through changes in growth conditions.

In this study, two new grades of oxide dispersion strengthened (ODS) Inconel 718 (IN718) alloys were designed by the thermochemical CALPHAD method and produced by laser powder bed fusion (LPBF) technique. Alloys designated as IN718-YF and IN718-YFH, that consist Y2O3 – FeO and Y2O3 - FeO - Hf, respectively, were fabricated with >99.9% densification using optimized process parameters. CALPHAD calculations were highly consistent with experimental findings, highlighting the formation of Al-containing Y-Ti-O and Y-Hf-O nano-oxides in both alloy types. Texture analyzes revealed no significant texture development in as-built (AB) or heat-treated (HT) alloys. Heat treatment was applied at 1050 °C for 1h to enhance nano-oxide density. The nano-oxide number density remained similar in IN718-YF while it decreased in IN718-YFH alloy as a result of carbide formation after the heat treatment. Besides, formation of secondary γ' particles was observed in the IN718-YFH / HT alloy. Even though the yield strengths of IN718-YF and IN718-YFH alloys in both AB and HT conditions were similar, the ductility of IN718-YFH was ∼50% less in almost all conditions compared to the ductility of IN718-YF. This has been shown to be as a result of irregular shaped micron-sized Y-Hf-O oxides, martensite formation in AB condition, increased amount of carbides and existence of secondary γ' particles in HT condition in IN718-YFH. High density of stacking faults (SF) forming at the interface of the nano-oxides have been detected in IN718-YF alloys. Besides dislocation/nanoparticle interactions, SFs which are responsible for the delocalization of the deformation improve the ductility of IN718-YF alloys. Overall, high temperature mechanical tests exhibit that both alloys have higher strength with improved ductility compared to the standard IN718 alloys, indicating the contribution of the nano-oxides.

Magnesium is widely used in industries, such as automotive, aerospace, and medical fields. The demand on magnesium has been growing, although the production and melt treatment is complex due to strong oxidation tendency. Recycling of magnesium scraps is crucial due to the criticality of magnesium-containing raw materials in Europe as well as increasing environmental concerns. Remelting of magnesium is typically conducted under a salt flux which absorbs the impurities and protects the melt against oxidation. This study investigates the effect of compaction, fused salt flux, and salt composition on remelting behavior of magnesium chips. Metal yield and coagulation efficiency were calculated after remelting, and samples were characterized by using Scanning Electron Microscope and X-ray Diffraction. The liquidus temperature and density of fluxes were analyzed by FactSage software. Remelting of compacted chips under a fused salt flux with 5 wt.% CaF2 showed the highest magnesium recovery with a yield of 97.7%. Le magnesium est largement utilise dans une variete d'industries, telles que les domaines de l'automobile, de l'aerospatiale et de la medecine. La demande en magnesium s'est accrue, bien que la production et le traitement du bain soient complexes en raison de sa forte tendance a l'oxydation. Le recyclage des dechets de magnesium est crucial en raison de la criticite des matieres premieres contenant du magnesium en Europe ainsi que des preoccupations environnementales croissantes. La refusion du magnesium est effectuee typiquement sous un flux de sel qui absorbe les impuretes et protege le bain contre l'oxydation. Cette etude examine l'effet du compactage, du flux de sel fondu et de la composition du sel sur le comportement a la refusion des copeaux de magnesium. On a calcule le rendement en metal et l'efficacite de la coagulation apres des experiences de refusion, et l'on a caracterise les echantillons a l'aide d'un microscope electronique a balayage et de la diffraction des rayons X. On a analyse la temperature du liquidus (Tliq) et la densite des flux de sel avec le logiciel FactSage. La refusion des copeaux compactes sous un flux de sel fondu avec 5% en poids de CaF2 a montre la recuperation de magnesium la plus elevee avec un rendement de 97.7%

This study investigates the cost-effective synthesis and thermomechanical processing of AlxCoCrFeNiCuy (x&y = 0.5,1) high-entropy alloys through cold (CR) and hot rolling (HR). The alloys were synthesized using a ther-mochemical modelling-assisted aluminothermic non-centrifugal, self-propagating high-temperature synthesis (SHS) method, which is reported for the first time in the literature. Remelting and suction casting were conducted via vacuum arc melting upon the compositional verification through x-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS) analyses. The deformabilities and hardness values of the alloys were correlated with microstructural changes that were analysed through scanning and transmission electron microscopy (SEM, TEM). Among the master alloys, FCC-A1 based Al0.5CoCrFeNiCu0.5 (Al0.5Cu0.5) and Al0.5CoCrFeNiCu (Al0.5Cu1.0) alloys exhibited highest cold deformability (145% and 170%, respectively), accompanied by sig-nificant work hardening (114% and 108% increase in hardness, respectively), primarily attributed to dislocation-dislocation interactions. It has been demonstrated for the first time that equiaxed single phase (FCC-A1) Al0.5CoCrFeNiCu0.5 high-entropy alloy can be obtained through the CR + annealing. The alloys exhibited reduced hot formability (62% and 85%, respectively) partly due to the formation of Cr-rich sigma phase instead of the Al-Ni rich B2 phase, most notable in the Al0.5Cu0.5 alloy, contrary to the CALPHAD simulations. This led to increased hardness in the alloys through precipitation hardening, achieving similar hardness values as those obtained through cold rolling (CR) with less deformation. The findings support the conclusion that the presented integrated processing strategy offers a cost-efficient means of producing Al0.5CoCrFeNiCuy alloys with enhanced mechanical and chemical properties for various engineering applications by the selection of cold and hot rolling routes.

In this study, the cost-effective synthesis, shaping and strengthening through hot and cold rolling of AlxCoCrFeNi (0.5 < x < 3) high-entropy alloys was investigated using an integrated processing method for the first time in the literature that involved non-centrifugal self-propagating high-temperature synthesis (SHS) followed by suction-casting. Compositions of the master alloys were well-controlled by virtue of thermochemical simulations (CALPHAD) and were acceptable for secondary processes. The FCC-based Al0.5CoCrFeNi alloy exhibited the highest hot deformability (36%) at 1000 degrees C among the all alloys resulting in a 109% increase in hardness, with respect to its as-cast state. It was possible to obtain Al0.5CoCrFeNi plates with improved hardness (42%) compared to the SHS master alloy, with substantial area reduction (131%) through the cold-rolling route. Despite the calculated phase diagram suggesting no sigma formation around 1000 degrees C, the hardness increase in the hot rolling process caused by the synergistic precipitation of BCC-B2 and s phases via hot deformation. It was concluded that the FCC-based Al0.5CoCrFeNi alloy can be successfully manufactured from oxides to final or semifinal products for applications requiring various thicknesses and improved mechanical properties through static or dynamic precipitation hardening by the selection of cold and hot rolling routes, respectively.

MAB phase AlFe 2 B 2 has attracted a lot of attention as a ternary transition metal boride with layered structure due to its near -room temperature magneto-caloric effect (MCE), composed of earth -abundant elements and other properties. In this work the electronic structure, chemical bonding characteristics, mechanical stability, elastic properties, and elastic anisotropy of AlFe 2 B 2 -based compounds (borides) have been investigated using firstprinciples calculations based on density functional theory (DFT). The substitution effect of transition metals (TM) Cr and V in AlFe (2-x) TM x B 2 (x = 0-1), (TM = Cr, V) compounds have been investigated. It was determined that all the elements added instead of the removed Fe element in the borides increased the mechanical properties such as hardness, brittleness, and isotropy. Moreover, it has been observed that hardness, brittleness, and isotropy increase with the increasing amount of the fourth alloying element. In AlFe (2-x) TM x B 2 , it has been observed that for x = 0.25 and 0.5 values, V causes an increase in stiffness more than Cr; however, for x = 1, while the increase in Cr continues to have an effect, a reverse trend is observed for V. Additionally, it has been observed that an increase in isotropy is significantly more influenced by Cr than by V. Among borides, it has been determined that AlFeCrB 2 exhibits the highest elastic moduli (bulk, shear, and Young's modulus), hardness, and isotropy.

In this study, the feasibility of the synthesis of AlxCoCrFeNiMoy (0.5 < x < 3, y = 0.5,1) alloys via cost and energy efficient thermochemical modelling assisted (FactSage (TM)) aluminothermic self-propagating high-temperature synthesis (SHS) method was investigated. In addition, selected SHS alloys were also suction-casted into a bar shape by using a vacuum arc melter and the microstructural changes and oxidation behaviour of selected alloys were investigated. The characterization results demonstrated that AlxCoCrFeNiMoy (0.5 < x < 3, y = 0.5,1) master alloys can be successfully synthesized via thermochemical modelling assisted SHS method with a substantial composition control. The microstructures of the SHS alloys were found to comprise of the FCC-A1, BCC (A2, B2) and sigma phases with varying fractions depending on the composition. Increasing Al content was found to increase the hardness of the alloys from 278 HV to 829 HV for the AlxCoCrFeNiMo0.5 system. For AlxCoCrFeNiMo system, on the other hand, it had an increasing effect from Al0.5 to Al1.0 (from 659 HV to 903 HV) initially and then decreased the hardness to the levels of 773 HV with the further addition of Al. Suction-cast alloys exhibited rather similar microstructures with similar phase constituents and hardness values. As a general trend primer B2 phase fraction was increased due to higher cooling rate. Oxidation studies revealed that the Al3.0Mo0.5 alloy, which has higher B2 content (919 HV), exhibited better oxidation resistance after 100 h of exposure to air at 800 degrees C. Postulated scaling mechanisms, supported with the CALPHAD simulations and Raman analyses, revealed the formation of non-protective spinel oxides and sublimation of volatile MoOx oxides before the stabilization of a protective M2O3 (M = Al,Cr) layer, especially for the AlCoCrFeNiMo alloy.

In this investigation, Ni(40)Ti(50)Cu(x)Fe(10−x) (x = 2.5, 5, 7.5) alloys were synthesized through the self-propagating high-temperature synthesis (SHS) process, employing preheating temperatures of 240 and 450 °C. To optimize thermal analysis, samples were drawn from the middle and upper sections of specimens exhibiting superior propagation results at a preheating temperature of 450 °C. Omitting additional heat treatment ensured a precise result interpretation. While the Ti50Ni40Fe2.5Cu7.5 sample displayed minimal variations in martensite and austenite transformation temperatures, others exhibited diverse transformation profiles. Apart from the B19' martensitic phase, distinct B19 martensitic phases were identified in Ti50Ni40Fe5Cu5 and Ti50Ni40Fe2.5Cu7.5 alloys, each showcasing unique transformation temperatures and full-width at half-maximum (FWHM) values. The inquiry unveiled that an increased Fe content prompted the segregation of Fex(Ni)Ti-based intermetallic phases from Cu-based phases, with this effect intensifying in alloys featuring higher Fe atomic ratios. This influence significantly impacted transformation temperature outcomes, overshadowing the inherent impact of the synthesis method.