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The impact of additives on the nanoscale structures of spin‐cast polymer composite films, particularly in polymer solar cells, is a topic of significant interest. This study focuses on the blend film comprising poly(thieno[3,4‐b]thiophene‐alt‐benzodithiophene) (PTB7) and [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM), exploring how additives like 1,8‐diiodooctane (DIO) influence the film structures spin‐cast from chlorobenzene solution. Combined results of specular X‐ray and neutron reflectivity, grazing‐incidence small‐ and wide‐angle X‐ray scattering (GISAXS and GIWAXS), and X‐ray photoelectron spectroscopy indicate that DIO could significantly enhance the dispersion of PC71BM and reduce composition inhomogeneity in the film. Time‐resolved GISAXS–GIWAXS with 100 ms resolution further captures a rapid spinodal decomposition of the mixture within 1 s in the constant‐evaporation stage of spin‐casting. Further combined with parallel analysis of time‐resolved UV–Vis reflectance, these findings reveal that DIO mitigates the spinodal decomposition process by accelerating solvent evaporation, which, in turn, decelerates phase segregation, leading to a nucleation‐driven process. These observations provide mechanistic insights into the role of additives in controlling the nanostructural evolution of spin‐cast films by altering the kinetics of solvent evaporation and phase separation during the spin‐coating process. [ABSTRACT FROM AUTHOR]

Medium-entropy Zr–Nb–Ti (ZNT) alloys are being extensively investigated as load-bearing implant materials because of their exceptional biocompatibility and corrosion resistance, and low magnetic susceptibility. Nevertheless, enhancing their yield strength while simultaneously decreasing their elastic modulus presents a formidable obstacle, significantly constraining their broader utilization as metallic biomaterials. In this study, three medium-entropy ZNT alloys, i.e., Zr 45 Nb 45 Ti 10 , Zr 42.5 Nb 42.5 Ti 15 , and Zr 40 Nb 40 Ti 20 (denoted ZNT 10 , ZNT 15 , and ZNT 20 , respectively), were designed based on the miscibility gap in the ZNT phase diagram and prepared by annealing of cold-rolled ingots. Their microstructures, mechanical properties, wear resistance, corrosion resistance, magnetic susceptibility, and biocompatibility were systematically studied. Spinodal decomposition occurred in the cold-rolled ZNT 10 and ZNTi 15 after annealing at 650 °C for 2 h and resulted in nanoscale Zr-rich β 1 and (Nb, Ti)-rich β 2 phases, which significantly improved their yield strength and reduced their elastic modulus. The wear resistance of the alloys decreased with an increase in Ti content. Dense ZrO 2 , Nb 2 O 5 , and TiO 2 oxide layers were formed during the polarization process in Hanks' solution, which enhanced the corrosion resistance of the alloys. These ZNT alloys exhibited significantly lower magnetic susceptibility than medical Ti alloys. The ZNT alloys showed a cell viability of more than 94 % toward MG-63 cells after culturing for 3 d Overall, the spinodal ZNT 15 showed the best combination of mechanical properties, wear resistance, corrosion resistance, low magnetic susceptibility, and sufficient biocompatibility among the three alloys. This work reports on medium-entropy Zr–Nb–Ti (ZNT) alloys with heterostructure. Spinodal decomposition significantly improved their mechanical strength and reduced the elastic modulus of the alloys. The wear resistance of the ZNT alloys decreased with an increase in Ti content. Dense ZrO 2 , Nb 2 O 5 , and TiO 2 oxide layers were formed during the polarization process in Hanks' solution, which enhanced the corrosion resistance of the alloys. The ZNT alloys exhibited significantly lower magnetic susceptibility than medical Ti alloys. The ZNT alloys showed a cell viability of >94 % toward MG-63 cells after culturing for 3 d The results demonstrate that spinodal ZNT alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, high corrosion resistance, wear resistance, low magnetic susceptibility, and sufficient biocompatibility. [Display omitted] [ABSTRACT FROM AUTHOR]

The research presented in this paper is part of a larger project concerning high-manganese alloys with different chemical compositions (mainly in manganese content from 21 to 31 wt.%). The presented examination results concern the analysis of the microstructure and textures in high-manganese X85MnAl29-9 steel, an age-hardenable steel, during aging at 550 °C for various times. X85MnAl29-9 steel was first hot rolled and subsequently cold rolled up to a 30% reduction. The samples were aged after deformation at 550 °C for various times in an argon atmosphere and cooled in air. The studies include X-ray phase analysis, texture measurement and observation of the microstructure by light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), as well as microhardness measurement. Research using scanning and transmission electron microscopy identified carbides in the analyzed samples. The results indicate that, when aging takes place, precipitation of κ′-carbide in an austenitic matrix and carbide κ at grain boundaries occurs. The appearance of satellites on diffraction patterns suggests that (Fe, Mn)3AlC nano-carbides are formed within the austenite matrix by a spinodal decomposition mechanism after the alloy is subjected to long-term aging, which is a key element for structure analysis in the design of safety systems. The use of shorter aging times (up to 24 h) leads to an increase in hardness caused by the precipitation of small κ′-carbide particles in the matrix. However, long aging times (100 h) lead to an increase in the precipitation of the carbide phase (κ and κ′), i.e., the steel becomes overage, which results in a decrease in hardness. [ABSTRACT FROM AUTHOR]

During the γ phase–δ phase transition, U-50Zr fuel experiences spinodal decomposition, which has a significant effect on fuel properties. However, little is known about the spinodal decomposition of U-50Zr. The spinodal decomposition behavior in U-50Zr is studied in this research using the phase-field approach. The mechanism of spinodal decomposition from a thermodynamic perspective is studied, and the effects of temperature and grain boundary (GB) on spinodal decomposition are analyzed. It is found that the concentration of U atoms in the U-rich phase formed during spinodal decomposition is as high as 90%. The U-rich phase first appears at the GB position, and precipitation phases appear inside the grain later. Ostwald ripening occurs when larger precipitation phases on the GB absorb isolated smaller precipitation phases inside the grain. The coarsening rate of precipitation phases and the time it takes for spinodal decomposition to achieve equilibrium are both influenced by temperature. [ABSTRACT FROM AUTHOR]

This study aimed at investigation of thermal aging effects on evolution of microstructure and mechanical properties of ER316L austenitic stainless-steel weld (ASSW). The ASSW was subjected to thermal aging at 400 °C for up to 30,000 h. Initially, thermal aging triggered spinodal decomposition of δ-ferrite and clustering of Ni. Thermal aging up to 20,000 h further enhanced spinodal decomposition and G-phase formation. After 30,000 h of aging, precipitation of Mo-rich χ-phase occurred adjacent to the G-phase. Concurrently, thermal aging induced segregation of different elements and formation of nickel depletion zone was observed at the ferrite/austenite (δ/γ) phase boundary. The consequence of these microstructure changes was the hardening of δ-ferrite and loss of fracture toughness of ASSW. However, after 30,000 h of aging at 400 °C, degraded fracture toughness and tensile properties were partially recovered. This recovery in fracture toughness was attributed to the evolution of microchemistry and the formation of a softer shell in the δ/γ phase boundary region.

Permanent magnets are essential components of electromechanical devices. Majority of magnets are used in permanent magnet motors that have extensive application in relation to energy efficiency and sustainability like electric vehicles. This research is aimed for efficient manufacturing of FeCrCo permanent magnets. Electromagnets could be utilized for the generation of continuous magnetic field to use in number of manufacturing processes. A two-pole electromagnet, comprising of two solenoids each having 2200 turns of copper wire, was developed. The system was designed to produce magnetic field up to 10 kilo Gauss for spinodal decomposition of FeCrCo alloy samples under thermomagnetic treatment process. Being rare earth free alloys, FeCrCo magnet is gaining research focus as an alternative magnetic alloy for advanced applications. The electromagnetic system design was refined and confirmed by using the Finite Element Method. The experimental values, of magnetic field generated by the two-pole electromagnet setup, were well close to the simulation results. The magnetizing setup was utilized to treat the FeCrCo magnetic alloy samples simultaneously at high temperature (700 °C) and magnetic field (7 kilo Gauss). This thermo-magnetic setup helped to improve the metallurgical structures of FeCrCo to grow and develop more efficiently. Treated samples of FeCrCo alloy demonstrated enhanced magnetic properties due to effective spinodal decomposition. The improvement in magnetic properties was attributed to the elimination of retained alpha phase and formation of more alpha-1 phase.

The double quench phase separation is a simplified type of continuous cooling process that is widely seen in industrial processes for polymeric membrane formation. Uncommon quenching conditions can lead to the creation of novel membrane microstructures. This study aims to theoretically investigate the impact of nonisothermality on the morphology formation during the double‐quench thermally‐induced phase separation process. First, quench is employed during different stages of phase separation to observe the possibility of secondary morphology formation. Next, two initial quench temperatures are selected, one shallow and the other deep. The initial solution temperature and the secondary quench temperature are kept constant to inspect the impact of the initial quench temperature on the structure formation. Lastly, the results of the secondary quench are compared with and without employing the enthalpy of demixing. Results verified that the stage of phase separation, the initial and secondary quench temperatures, cooling rate, and the secondary quench composition are the most important parameters in the the nonisothermal double quench phase separation process. The morphology should be well‐developed in order for the secondary structure formation. In addition, it is shown that heat generation during demixing in the primary and secondary quenches significantly influences the secondary morphology formation. [ABSTRACT FROM AUTHOR]

Cobalt-based ternary superalloys were prepared from the consolidation of high purity cobalt, tungsten and tantalum elemental powder using spark plasma sintering technique. The composition of the alloys was fixed, so also were the sintering pressure (50 MPa) and heating rate (150 °C/min). However, the samples sintering temperatures were varied from 800 to 1400 °C, with holding time of 10 and 15 min. The microstructure, phase and crystallographic characterizations were done using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), optical microscopy and X-ray diffraction spectroscopy. Mechanical properties of the Co-alloys were evaluated using Vickers microhardness analytical data. Sintering data analysis indicates a two-step major and minor densification modes in the samples, and morphological images show evolution in the microstructure based on varied sintering parameters. Phase partitioning due to spinodal decomposition was observed in the alloys (1000 to 1400 °C). Crystallographic peak intensities were observed to increase with sintering temperature up to 1200 °C, whereas structural amorphization occur at 1400 °C. The microhardness improved from 358.74 to 594.64 HV for sintered alloy at 1200 °C. Alloy samples sintered at 1200 °C and of 10 min dwelling time have optimum mechanical property. [ABSTRACT FROM AUTHOR]

The spinodal decomposition method emerges as a promising methodology, showcasing its potential in exploring the design space for metamaterial structures. However, spinodal structures design is still largely limited to regular structures, due to their relatively easy parameterization and controllability. Efficiently predicting the mechanical properties of 3D spinodal membrane structure remains a challenge, given that the features of the membrane necessitate adaptive mesh through the modelling process. This paper proposes an integrated approach for morphological design with customized mechanical properties, incorporating the spinodal decomposition method and adaptive coarse-grained modeling, which can produce various morphologies such as lamellar, columnar, and cubic structures. Pseudo-periodic parameter β and orientational parameter Θ(θ1, θ2, θ3) are identified to achieve the optimal goal of anisotropic mechanical properties. Parametric analysis is conducted to reveal the correlation between the customized spinodal structure and mechanical performance. Our work provides an integrated approach for morphological variation and tuning mechanical properties, paving the way for the design and development of customized functional materials similar to 3D spinodal membrane structures. [ABSTRACT FROM AUTHOR]

Metallic biomaterials, such as stainless steels, cobalt–chromium–molybdenum (Co–Cr–Mo) alloys, and titanium (Ti) alloys, have long been used as load-bearing implant materials due to their metallic mechanical strength, corrosion resistance, and biocompatibility. However, their magnetic susceptibility and elastic modulus of more than 100 GPa significantly restrict their therapeutic applicability. In this study, spinodal Zr 60 Nb 40 , Zr 50 Nb 50 , and Zr 40 Nb 60 (at.%) alloys were selected from the miscibility gap based on the Zr–Nb binary phase diagram and prepared by casting, cold rolling, and aging. Their microstructure, mechanical properties, corrosion resistance, magnetic susceptibility, and biocompatibility were systematically evaluated. Spinodal decomposition to alternating nanoscale Zr-rich β 1 and Nb-rich β 2 phases occurred in the cold-rolled Zr–Nb alloys during aging treatment at 650 °C. In addition, a minor amount of α phase was precipitated in Zr 60 Nb 40 due to the thermodynamic instability of the Zr-rich β 1 phase. Spinodal decomposition significantly improved the mechanical strength of the alloys due to nanosized dual-cubic reinforcement. The Zr–Nb alloys showed an electrochemical corrosion rate of 94–262 nm per year in Hanks' solution because of formation of dense passive films composed of ZrO 2 and Nb 2 O 5 during the polarization process. The magnetic susceptibilities of the Zr–Nb alloys were significantly lower than those of commercial Co–Cr–Mo and Ti alloys. The cell viability of the Zr–Nb alloys was more than 98 % toward MC3T3-E1 cells. Overall, the spinodal Zr–Nb alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, extraordinary corrosion resistance, low magnetic susceptibility, and sufficient bicompatibility. This work reports on spinodal Zr–Nb alloys with heterostructure. Spinodal decomposition significantly improved their mechanical strength due to the nanosized dual-cubic reinforcement. The Zr–Nb alloys showed large corrosion resistance in Hanks' solution because of formation of dense passivation films composed of ZrO 2 and Nb 2 O 5 during the polarization process. The magnetic susceptibilities of the Zr–Nb alloys were significantly lower than those of commercial Co–Cr–Mo and Ti alloys. The cell viability of the Zr–Nb alloys was more than 98 % toward MC3T3-E1 cells. The results demonstrate that spinodal Zr–Nb alloys have enormous potential as bone-implant materials due to their outstanding overall mechanical properties, high corrosion resistance, low magnetic susceptibility, and sufficient biocompatibility. [Display omitted] [ABSTRACT FROM AUTHOR]

As the marine industry progresses, copper-containing metallic materials that possess both high strength and ductility are demanding. Traditional copper alloys used in marine environment face challenges regarding inadequate strength and corrosion resistance. In the present work, cold rolling and subsequent high-temperature annealing processes were employed to the Cu1.2NiMnFe0.5Cr0.5Al0.2 high-entropy alloy. This alloy exhibited remarkable mechanical properties, including a yield strength (YS) of 530 MPa, ultimate tensile strength (UTS) of 913 MPa, and a relatively high fracture elongation (EL) of 37.7%. After subsequent aging treatment at 400 °C, spinodal decomposition occurred within the matrix, leading to enhanced strength. The decomposed microstructure was comprehensively characterized, and the strengthening mechanism was analyzed. Notably, the sample aged for 6 h exhibited a YS of 701 MPa and an EL of 21.8%. The present HEAs exhibit superior mechanical properties compared to traditional copper alloys and other Cu-containing HEAs, when considering both strength and ductility. Furthermore, these alloys demonstrated exceptional corrosion resistance and a favorable copper ion release rate in 3.5 wt% NaCl solution. This work introduces an innovative class of advanced alloys and offers a strategic approach to alloy design for marine applications.

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The research focus in the field of medical titanium alloys has recently shifted towards the development of low-modulus and high-strength titanium alloys. In this study, the influence of aging temperature on the microstructure and mechanical properties of a β-type Ti-20Zr-40Ta alloy (TZT) was investigated. It was found that the recovery and the recrystallization occurred in the as-rolled alloy depended on the aging temperature. The periodically distributed Ta-lean phase (β1) and Ta-rich phase (β2) were produced by the spinodal decomposition in all the samples aged at different temperatures. The spinodal decomposition significantly influenced the mechanical properties and deformation mechanisms of the TZT alloy. Upon aging at 650 °C and 750 °C, the as-rolled alloy exhibited a double-yield phenomenon during tensile testing, indicating a stress-induced martensitic transformation; however, its ductility was limited due to the presence of ω phases. Conversely, aging at 850 °C resulted in an alloy with high strength and good ductility, which was potentially attributed to the enhanced strength resulting from modulated structures introduced with spinodal decomposition. [ABSTRACT FROM AUTHOR]

Optimizing the spinodal decomposition structure in Alnico magnets is a very effective way to improve the performance. Some elemental additives are extremely sensitive to the spinodal decomposition process. In this manuscript, the evolution of spinodal decomposition structure in isotropic Alnico 8 ribbons with various Ti contents and its effects on magnetic properties and service performance are investigated. Alnico 8 ribbons with nominal composition of different Ti content (3.5 wt%-7.5 wt%) were prepared by melt-spinning and simplified heat treatment. The optimum magnetic properties of the ribbons such as intrinsic coercivity, Hcj=860 Oe, remanence magnetization, Br =5.89 kGs, and maximum magnetic energy product, (BH)max=1.2 MGOe are obtained for 5.5 wt% Ti. The ribbons show excellent temperature stability, their magnetic properties are 100% reversible up to 800 K and can be maintained above 85% at 800 K. The increase of Ti decreases the Curie temperature of the ribbons slightly. The evolution of spinodal decomposition phases and its influence mechanisms on magnetic properties are studied. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the degree of low-temperature phase separations and 475 °C -embrittlement in physically simulated multipass super duplex stainless steel (SDSS) welds. A single bead weld was produced using gas metal arc welding and multiple thermal cycles with different peak temperatures were applied using a Gleeble physical simulator with fixed and moving jaws to simulate the influence of constrained designs, to mimic the welding of thick SDSS components. The samples were studied using atom probe tomography and the results were correlated with toughness and ferrite microhardness. The results showed that the microhardness of the ferrite in the constrained simulated multipass reheated weld increased from 304 HV to 374 HV after 5 min aging at 475 °C. The amplitude of the Cr concentration of the same sample, showing the level of Fe-Cr phase separation, increased from 1.025 to 1.045 after 5 min aging at 475 °C. Despite the clear development of phase separation in the ferrite, the toughness did not drop. It can be concluded that reheated SDSS welds are not susceptible to 475 °C -embrittlement during short fabrication times of up to 5 min for the austenite level of 50%. [ABSTRACT FROM AUTHOR]

To study the formation and transformation mechanism of long-period stacked ordered (LPSO) structures, a systematic atomic scale analysis was conducted for the structural evolution of long-period stacked ordered (LPSO) structures in the Mg-Gd-Y-Zn-Zr alloy annealed at 300 °C∼500 °C. Various types of metastable LPSO building block clusters were found to exist in alloy structures at different temperatures, which precipitate during the solidification and homogenization process. The stability of Zn/Y clusters is explained by the first principles of density functional theory. The LPSO structure is distinguished by the arrangement of its different Zn/Y enriched LPSO structural units, which comprises local fcc stacking sequences upon a tightly packed plane. The presence of solute atoms causes local lattice distortion, thereby enabling the rearrangement of Mg atoms in the different configurations in the local lattice, and local HCP-FCC transitions occur between Mg and Zn atoms occupying the nearest neighbor positions. This finding indicates that LPSO structures can generate necessary Schockley partial dislocations on specific slip surfaces, providing direct evidence of the transition from 18R to 14H. Growth of the LPSO, devoid of any defects and non-coherent interfaces, was observed separately from other precipitated phases. As a result, the precipitation sequence of LPSO in the solidification stage was as follows: Zn/Ycluster+Mg layers→various metastable LPSO building block clusters→18R/24R LPSO; whereas the precipitation sequence of LPSO during homogenization treatment was observed to be as follows: 18R LPSO→various metastable LPSO building block clusters→14H LPSO. Of these, 14H LPSO was found to be the most thermodynamically stable structure.

Pressure is a critical component of preparation processes regardless of its magnitude, whether it is a few megapascals, such as in metal squeeze casting, or thousands of megapascals, such as in the experimental preparation of amorphous materials, quasicrystals and nanocrystals. Spinodal decomposition and ordering are two common forms of unstable phase transformation in solid solutions. Reasonable regulation of these two transformations can effectively control microstructures and improve properties. Therefore, the study of solid solution instability under the effect of ultrahigh pressure is of great significance for regulating the properties of high-entropy alloys (HEAs). From this perspective, CoCrFeNiAl HEAs were prepared under pressures of ambient pressure, 4 GPa and 7 GPa. Both solid spinodal decomposition and ordering of the BCC structure were detected when CoCrFeNiAl HEAs are solidified at ambient pressure. Nevertheless, after high-pressure solidification, liquid‒liquid phase spinodal decomposition occurred. One phase was rich in (Fe, Cr), and the other phase was rich in (Ni, Al). Both phases experienced solid spinodal decomposition during cooling. Discontinuous precipitates were generated in the (Ni, Al)-rich solid phase, each with a size of approximately 1.4 μm. Furthermore, a graphic thermodynamic model was established to reveal the solidification behavior. After solidification at 7 GPa, the corrosion rate of the alloy decreased by 98.3 %; that is, the high pressure greatly improved the corrosion resistance of the alloy. This improvement was attributed to the influences of high pressures on the dynamics of spinodal decomposition processes.

It has been proposed that the intrinsic property of nucleosome arrays to undergo liquid-liquid phase separation (LLPS) in vitro is responsible for chromatin domain organization in vivo. However, understanding nucleosomal LLPS has been hindered by the challenge to characterize the structure of the resulting heterogeneous condensates. We used cryo-electron tomography and deep-learning-based 3D reconstruction/segmentation to determine the molecular organization of condensates at various stages of LLPS. We show that nucleosomal LLPS involves a two-step process: a spinodal decomposition process yielding irregular condensates, followed by their unfavorable conversion into more compact, spherical nuclei that grow into larger spherical aggregates through accretion of spinodal materials or by fusion with other spherical condensates. Histone H1 catalyzes more than 10-fold the spinodal-to-spherical conversion. We propose that this transition involves exposure of nucleosome hydrophobic surfaces causing modified inter-nucleosome interactions. These results suggest a physical mechanism by which chromatin may transition from interphase to metaphase structures.

In this paper, the features of the formation of bulk InGaN layers with an indium content of ~ 60% in the immiscibility gap of InGaN ternary solid solutions by the method of molecular-beam epitaxy with plasma nitrogen activation are studied. The structures under study were grown on sapphire substrates, while the epitaxy temperature and the ratio of metal (In + Ga) and activated (atomic) nitrogen fluxes were varied. It has been demonstrated that the rates of thermal decomposition and phase separation for In0.6Ga0.4N ternary solutions depend nonmonotonically on the growth temperature in the range Tgr = 430–470°C. It is shown that InGaN thermal decomposition processes occur on the growth surface and lead to the appearance of surface phases of metallic In and binary InN, while phase separation leads to the appearance of InGaN phases of various compositions throughout the volume of the deposited InGaN layer. It is shown that, in the temperature range under study, phase separation is determined by surface diffusion, which can be suppressed by growth under highly nitrogen-enriched conditions, which made it possible to obtain homogeneous InGaN layers with an In content of In ~ 60% during high-temperature (Tgr = 470°C) growth. It is shown that the suppression of InGaN thermal decomposition processes is decisive in achieving effective interband luminescence of the obtained structures, while the presence of phase separation affects the radiative properties of InGaN layers to a lesser extent, at least in the region of low (T = 77 K) temperatures. [ABSTRACT FROM AUTHOR]

(Zr 0.196 Hf 0.02 V 0.196 Nb 0.196 Mo 0.196 W 0.196)C x complex concentrated ceramics (CCC) with variable carbon non-stoichiometry are fabricated by hot-pressing sintering at 2100 °C for 1 h. The influence of carbon content on phase decomposition behavior and microstructural evolution is investigated. With the decreasing carbon content, the phase transformation of single-phase solid solution → discontinuous precipitation → spinodal decomposition → single-phase occurs, consistent to the binary phase diagram with miscibility gap. The single-phase solid solution decomposes into (ZrHfNb)C-rich and (VMoW)C-rich phases during the phase separation. For spinodal decomposition, the nodular microstructure is formed with coherent crystal orientation relationship of (ZrHfNb)C-rich phase {011} // (VMoW)C-rich phase {011}. The spinodal decomposition leads to in-situ hardening and toughening effects due to the interface hardening and fine microstructure. The spinodal decomposition into two high entropy phases could potentially be beneficial to tailor properties and demonstrated in a future work. [ABSTRACT FROM AUTHOR]

To study the formation and transformation mechanism of long-period stacked ordered (LPSO) structures, a systematic atomic scale analysis was conducted for the structural evolution of long-period stacked ordered (LPSO) structures in the Mg-Gd-Y-Zn-Zr alloy annealed at 300 °C∼500 °C. Various types of metastable LPSO building block clusters were found to exist in alloy structures at different temperatures, which precipitate during the solidification and homogenization process. The stability of Zn/Y clusters is explained by the first principles of density functional theory. The LPSO structure is distinguished by the arrangement of its different Zn/Y enriched LPSO structural units, which comprises local fcc stacking sequences upon a tightly packed plane. The presence of solute atoms causes local lattice distortion, thereby enabling the rearrangement of Mg atoms in the different configurations in the local lattice, and local HCP-FCC transitions occur between Mg and Zn atoms occupying the nearest neighbor positions. This finding indicates that LPSO structures can generate necessary Schockley partial dislocations on specific slip surfaces, providing direct evidence of the transition from 18R to 14H. Growth of the LPSO, devoid of any defects and non-coherent interfaces, was observed separately from other precipitated phases. As a result, the precipitation sequence of LPSO in the solidification stage was as follows: Zn/Ycluster+Mg layers→various metastable LPSO building block clusters→18R/24R LPSO; whereas the precipitation sequence of LPSO during homogenization treatment was observed to be as follows: 18R LPSO→various metastable LPSO building block clusters→14H LPSO. Of these, 14H LPSO was found to be the most thermodynamically stable structure. [ABSTRACT FROM AUTHOR]

Spinodal decomposition of the ferritic phase, a thermally induced phase transformation process is studied in an LDX 2101 type leanduplex stainless steel by different examination methods. This phase transformation in duplex stainless steels has special importance because it is responsible for the so called "475 °C embrittlement". This deterioration process causes a decrease in toughness and corrosion resistance. Fe-Cr alloys, thus several stainless steels, are susceptible to the spinodal decomposition at intermediate and low temperatures (<600 °C). Therefore, it is important to study this phenomenon in novel lean-duplex stainless steels as well. Our results revealed that spinodal decomposition occurs to a lesser extent in the studied type of lean-duplex stainless steel but its effect is not negligible in applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel multicomponent alloy Al58Zn28Mg6Si8, with a density of 3.46 g/cm3, which incorporates concepts from high entropy alloys. The optimum alloy composition was determined using the CALPHAD approach and binary and ternary diagrams. Microstructural and thermal analyses, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry, revealed a complex phase structure consisting of FCC, HCP, and Laves phases, as well as a metastable miscibility gap. The alloy was heat treated, and the microstructure of each condition was evaluated. The solubilized state exhibited a maximum hardness of 250 HV. Transmission electron microscopy results showed that the alloy undergoes spinodal decomposition during the solution treatment. This study provides valuable information for the future design of lightweight multicomponent alloys combining experimental techniques with the CALPHAD approach.

During the γ phase–δ phase transition, U-50Zr fuel experiences spinodal decomposition, which has a significant effect on fuel properties. However, little is known about the spinodal decomposition of U-50Zr. The spinodal decomposition behavior in U-50Zr is studied in this research using the phase-field approach. The mechanism of spinodal decomposition from a thermodynamic perspective is studied, and the effects of temperature and grain boundary (GB) on spinodal decomposition are analyzed. It is found that the concentration of U atoms in the U-rich phase formed during spinodal decomposition is as high as 90%. The U-rich phase first appears at the GB position, and precipitation phases appear inside the grain later. Ostwald ripening occurs when larger precipitation phases on the GB absorb isolated smaller precipitation phases inside the grain. The coarsening rate of precipitation phases and the time it takes for spinodal decomposition to achieve equilibrium are both influenced by temperature.

The microstructural features of a high-strength body-centered cubic Mg-Li–Al-Ag alloy are investigated and the strengthening mechanisms are discussed. The results show that obvious spinodal decomposition occurs in the alloy. Owing to the diffusion of Al atoms to Ag-vacancy pairs, co-clustering of Al and Ag is observed. The compositional redistribution of Li in the matrix reduces the interfacial lattice misfit and thus lowers the strain energy. Combinatorial spinodal strengthening with coherency strain hardening result in high strength achieved in the Mg-Li–Al-Ag alloy. The dual alloying strategy opens avenues for tuning the microstructure and enhancing mechanical properties of Mg-Li alloys.

The multi-layer composite development primarily aims to develop and test the components of the next generation of hadron colliders (e.g., Large Hadron Collider - LHC) consisting of superconducting raw materials. Multilayer sheet is very similar to the commonly used NbTi wire products, a 2D version of the commercial wire. These composites consist of layers such as NbTi superconductor, Nb diffusion barrier (between NbTi and Cu) and Cu stabilizer. In β-NbTi superconducting alloys, α-Ti precipitates are primary flux pinning centers that maintain stable superconductivity. A multi-step series of heat treatments and cold-forming processes can develop the flux pinning centers. Practically, this process means three heat treatments of constant period and temperature and drawing or rolling between the heat treatments.The study aimed to describe the behavior of the cold-rolled (ε = 3.35) Nb53Ti47w% alloys during isothermal heating at 673 K as a function of heating time. The processes during the aging were investigated by the in-situ XRD method in the heating chamber. The X-ray diffraction patterns were evaluated by Rietveld refinement. The thermally activated spinodal decomposition and precipitation processes were described based on the phases identified at the individual heat treatment steps and their lattice parameters. The in-situ study also revealed an increase in α-Ti precipitation with time and decomposition that co-occurs. This is the basic study that prepares the applicability of the alloy.

The phase-field method, coupled with the micro-elastic model and irradiation-induced cascade mixing model, has been employed to investigate the spinodal decomposition in U-Mo and U-Mo-Zr alloys. The microstructure evolution of U-Mo or U-Mo-Zr alloys under different initial conditions, such as the alloy composition, aging temperature and irradiation intensity, were simulated to study the effect of cascade mixing on the miscibility gap, morphology and volume fraction of the decomposed phases. The simulation results demonstrate that irradiation-induced cascade mixing impedes the process of spinodal decomposition, and that irradiation shrinks the composition range of the miscibility gap in the alloys. Irradiation-induced cascade mixing slows down the anisotropic growth rate of the spinodal decomposition, yet this phenomenon can be weakened with increasing aging temperature. Adding an appropriate amount of Zr to a U-Mo alloy can effectively prevent the contraction of the miscibility gap caused by irradiation. [ABSTRACT FROM AUTHOR]

The criterion of formation of a modulated structure by means of the spinodal mechanism in a spatial distribution of interacting vacancies (as strong concentrators of mechanical stresses) in metals as a target after irradiation is analyzed. For the irradiated body-centered cubic vanadium and tungsten, temperature dependences of the spatial periods of such a structure of the substitutional-vacancies' subsystem are predicted taking into account the total mixing energies consisting of the energies of the (electro)chemical and strain-induced interactions between vacancies, which are cohesive by the nature in short distances and elastic by character at long distances, respectively. [ABSTRACT FROM AUTHOR]

Fe-Cr-Co is a typical spinodal decomposition type magnetic alloy. FeCrCo alloys being highly workable are important for slender feature designs and ductile applications. However, due to the rising prices of cobalt, research is increasingly being focused toward reducing the amount of cobalt in FeCrCo semi-hard magnetic alloys, without compromising on their magnetic properties. Silicon is ferrite stabilizer and therefore, can be utilized as a potential alloying element. Few researchers have reported work on addition of silicon in FeCrCo alloys, especially on the double isothermal magnetic field annealing. In this work, FeCrCo alloy with 2% silicon addition was produced and subjected to different heat treatments. An electromagnetic setup equipped with a tube furnace was designed based on Finite Element Method (FEM) analysis, and developed for thermomagnetic treatments. An increase in remanence for double thermomagnetic treatment was noted. This improvement could be attributed to the transformation of retained α phase into α1 phase. It was also observed that the squareness of the M-H curve improved with the double treatment. [ABSTRACT FROM AUTHOR]

Based on the excellent comprehensive mechanical properties of high–entropy alloy (HEA), the NiAl-based HEA was designed to achieve excellent high-temperature strength, toughness, and wear resistance. In this work, vacuum arc melting technology was used to prepare (NiA1)78(CoCrFe)16.5Cu5.5 HEA, and its microstructure, phase composition, and mechanical properties were systematically studied. The results showed that (NiA1)78(CoCrFe)16.5Cu5.5 HEA was composed of FCC and BCC/B2, with a spinodal decomposition structure in the matrix, and nano-precipitation in the interdendritic, exhibiting a good high-temperature performance. At 600 °C, the compressive fracture strength is 842.5 MPa and the fracture strain is 24.5%. When the temperature reaches 800 °C, even if the strain reaches 50%, the alloy will not fracture, and the stress–strain curve shows typical work hardening and softening characteristics. The wear coefficient of the alloy first increases and then decreases with the increase in temperature in the range of room temperature to 400 °C. However, the specific wear rate shows the opposite trend. At 100 °C, the wear rate reaches the lowest of 7.05 × 10−5 mm3/Nm, and the wear mechanism is mainly abrasive wear. [ABSTRACT FROM AUTHOR]

In high‐viscosity polymer solutions and blends, temperature variations during the quench process of the thermally‐induced phase separation (TIPS) influence the dynamics and thermodynamics of phase separation. Hence, this study aims to investigate the impact of temperature variations on the morphology formation during the TIPS process. First, the influence of temporal temperature variations on phase separation is investigated by coupling a transient heat conduction model and the Cahn–Hilliard equation, and the results are compared with the isothermal phase separation process. Next, the morphology formation during phase separation is inspected by applying quench from two opposite sides of the sample to the same and different temperatures through coupling the Fourier heat transfer equation and the Cahn–Hilliard equation. The influence of the enthalpy of demixing on the morphology formation and the competition between the heat and mass transfer is also evaluated. It is confirmed that temporal variations of temperature alone have a significant impact on the morphology formation during the TIPS process. In addition, quenching the system to the same and different temperatures both leads to anisotropic morphology formation, which is affected by the quench rate, quench temperature, solution viscosity, and enthalpy of demixing. Upon applying different quench temperatures from opposite sides, two different types of morphologies and droplet sizes were formed as a result of the difference in the cooling rates between the two sides. Employing the enthalpy of demixing during phase separation induced a shallow quench effect on the deep quench side due to the fact that the heat moved toward the lowest temperature in the system, which led to the formation of a distinctive structure. [ABSTRACT FROM AUTHOR]

By integrating calculation of phase diagram (CALPHAD) simulations, ab initio molecular dynamics (AIMD) and experimental validation, we shed light on the unexpected spinodal decomposition in as-cast Al30Co10Cr30Fe15Ni15 alloy, as opposed to the eutectic BCC/B2 microstructure predicted by CALPHAD. We showed that the eutectic high entropy alloy (EHEA) and spinodal decomposition (SD) may be correlated with each other. A shift from as-cast EHEA to SD can be triggered by the strong short-range ordering in the EHEA liquid phase and high configuration entropy of the metastable phase. CALPHAD showed that the low eutectic temperature of Al30Co10Cr30Fe15Ni15 alloy is stabilized by the short-range and topological ordering (SRO), rendering a small undercooling ΔT for partitionless solidification of the metastable B2 phase. AIMD calculations showed that the particular metastable-like liquid preordering might reduce interface energy between the eutectic liquid and saturated B2, facilitating metastable saturated phase formation even with a small undercooling and suppressing the eutectic reaction. The single B2 phase might have solidified in the spinodal region of the phase diagram resulting in a shift from as-cast EHEA to SD. The interplay between SD and EHEAs presents an alternative route to explore spinodal HEAs by simple as-casted samples without lengthy heat treatments for homogenization.

The precipitation of Cu-rich phases during the irradiation process will reduce radiation resistance in Fe-Cu-Mn-Ni reactor pressure vessel steels. Therefore, high-entropy alloys with excellent radiation resistance are expected to replace reactor pressure vessel steels and become structural materials for fusion and generation IV fission reactors. This study investigated the phase formation, spinodal decomposition tendency, and radiation resistance of the FeCuMnNi high entropy alloy using a multi-scale method. The results show that FeCuMnNi alloy has a dual-phase face-centered-cubic structure. Here, for the first time, we found that the precipitation phase of the FeCuMnNi high-entropy alloy during the irradiation process is a Mn-rich phase rather than a Cu-rich phase found in conventional Fe-Cu-Mn-Ni reactor pressure vessel steels. Mn separates from the Cu-Mn-rich phase and forms Fe-Mn-Ni clusters with a Fe-Ni phase during irradiation.

The nano-dimple fracture complexions assessed from the published tensile fracture surfaces are perceived to predict the trend of variation in deformation and fracture properties of a supersaturated nanocrystalline face-centered cubic Cu–Co alloy with systematic isothermal annealing treatment. The alteration of different microstructural disposition that led to change in fracture complexions have been quantified, compared and interpreted with the respective mechanical properties of the alloy. [ABSTRACT FROM AUTHOR]

The physical properties of a polymer solution that are composition- and/or temperature-dependent are among the most influential parameters to impact the dynamics and thermodynamics of the phase separation process and, as a result, the morphology formation. In this study, the impact of composition- and temperature-dependent density, heat capacity, and heat conductivity on the membrane structure formation during the thermally induced phase separation process of a high-viscosity polymer solution was investigated via coupling the Cahn–Hilliard equation for phase separation with the Fourier heat transfer equation. The variations of each physical property were also investigated in terms of different boundary conditions and initial solvent volume fractions. It was determined that the physical properties of the polymer solution have a noteworthy impact on the membrane morphology in terms of shorter phase separation time and droplet size. In addition, the influence of enthalpy of demixing in this case is critical because each physical property showed a nonhomogeneous pattern owing to the heat generation during phase separation, which in turn influenced the membrane morphology. Accordingly, it was determined that investigating spinodal decomposition without including heat transfer and the impact of physical properties on the morphology formation would lead to an inadequate understanding of the process, specifically in high-viscosity polymer solutions. [ABSTRACT FROM AUTHOR]

Herein, the occurrence of a B2-phase separation and formation of Cr-rich nanoprecipitates during the solidification process of AlCoCrFeNi2.1 eutectic highentropy alloy is addressed. Toward this end, various advanced characterizations, including high-resolution transmission electron microscopy and atom probe tomography combined with thermodynamic calculations, are employed. The as-solidified microstructure is composed of face-centered cubic (FCC) dendrites and interdendritic regions consisting of a eutectic mixture of FCC and bodycentered cubic (BCC) phases. The presence of uniformly distributed Cr-rich nanoprecipitates is traced through the BCC B2 phase in the interdendritic area. Regarding the occurrence of upward diffusion and Gibbs free energy variation, the formation of Cr-rich nano-precipitates is attributed to the spinodal decomposition where the critical temperature of 800 °C is passed behind during the solidification process. The formation of dense dislocation array in the interdendritic region due to thermal stress induced during solidification is introduced as a pathway for diffusion of alloying elements in the course of cooling stage. [ABSTRACT FROM AUTHOR]

The microstructural features of a high-strength body-centered cubic Mg-Li–Al-Ag alloy are investigated and the strengthening mechanisms are discussed. The results show that obvious spinodal decomposition occurs in the alloy. Owing to the diffusion of Al atoms to Ag-vacancy pairs, co-clustering of Al and Ag is observed. The compositional redistribution of Li in the matrix reduces the interfacial lattice misfit and thus lowers the strain energy. Combinatorial spinodal strengthening with coherency strain hardening result in high strength achieved in the Mg-Li–Al-Ag alloy. The dual alloying strategy opens avenues for tuning the microstructure and enhancing mechanical properties of Mg-Li alloys. Solutes co-clustering and solvents redistribution are responsible for high strength achieved in ultralight BCC Mg-Li-base alloys, which provide strategy for optimizing mechanical properties in such alloys. [ABSTRACT FROM AUTHOR]

The deformation behavior of δ-ferrite in an aged austenitic stainless-steel weld was investigated to obtain insights on the contribution of aging-induced nanofeatures, such as spinodal decomposition and G-phase precipitation, to aging embrittlement. To evaluate the hardening effect of the G-phase, a reversion heat treatment was applied to the aged weld. The strengthening effect of spinodal decomposition and the G-phase was measured using nanopillar compression tests. The deformed microstructure exhibited the dissolution of G-phases but a slight change in the spinodal nanostructure, indicating a clear difference in the stability of the nanofeatures during deformation. The quantitative measurement of the G-phase and the application of the Orowan model showed that the measured strengthening effect from the G-phase was less than that of the estimation, implying that the G-phase was not as effective as an impenetrable obstacle. On the other hand, spinodal decomposition showed high stability after deformation, leading to a noticeable hardening effect.

The results of studies of the structures of rapidly solidified foils of alloys of the Sn – Zn system with a low content of alloying elements (up to ~1,5 wt.%), alloys of near-eutectic compositions, as well as alloys with an alloying element content of 20 – 95 wt.% are presented. In rapidly solidified alloys containing 1,5 wt. % Sn and 1,2 wt. % Zn, supersaturated solid solutions are formed, which decompose according to the mechanism of formation and growth of nuclei of a new phase at room temperature. Alloys (4,4 – 15 wt.% Zn) after rapidly solidification are supercooled and supersaturated with both components, and experience spinodal decomposition followed by the formation of supersaturated solid solutions based on Sn and Zn, which decompose at room temperature. In all other alloys, a two-phase structure is formed from solid solutions based on Sn and Zn. It was found that as the crystallization front moves from the surface of the contacting foil layer with the surface of the mold, the Sn particles coarsen and the specific surface of the interface decreases. It has been established that rapidly solidified foils have a microcrystalline grain structure, with an increase in the concentration of alloying elements, a tendency to a decrease in grain size is observed.

The high-entropy alloy (Al25Fe30Mn25Ni20)1−xNdx (all in at.%) (AlFeMnNi)1−xNdx) was prepared by vacuum arc melting (AM) and casting method (CM). X-Ray Diffraction (XRD) and Scanning Electron Microscopy, transmission electron microscope and Integrated Energy-Dispersive X-ray spectroscopy were used to study the structure of our system. The (Al25Fe30Mn25Ni20)1−xNdx crystallises in a Face-centred cube and centred cubic (BCC), depending on the x (x = 0.00, x = 0.01 at.% Nd). The increase of Neodymium (0.01 at.% Nd) content results in the formation of BCC structure. The chemical composition analysis of FCC and BCC crystal structures, their lattice constants demonstrate that the formation of a single BCC solid solution between 760°C and 1480°C. The Korringa–Kohn–Rostoker Method and Green's function combined with coherent potential approximation were used to study the magnetoelectronic properties of (Al25Fe30Mn25Ni20)1−xNdx. We have obtained the value optimised of lattice parameter 2.9 Å and it is near to that obtained by experimental value using High Score programme and results XRD experimental. [ABSTRACT FROM AUTHOR]

The high-entropy alloy (Al25Fe30Mn25Ni20)1−xNdx (all in at.%) (AlFeMnNi)1−xNdx) was prepared by vacuum arc melting (AM) and casting method (CM). X-Ray Diffraction (XRD) and Scanning Electron Microscopy, transmission electron microscope and Integrated Energy-Dispersive X-ray spectroscopy were used to study the structure of our system. The (Al25Fe30Mn25Ni20)1−xNdx crystallises in a Face-centred cube and centred cubic (BCC), depending on the x (x = 0.00, x = 0.01 at.% Nd). The increase of Neodymium (0.01 at.% Nd) content results in the formation of BCC structure. The chemical composition analysis of FCC and BCC crystal structures, their lattice constants demonstrate that the formation of a single BCC solid solution between 760°C and 1480°C. The Korringa–Kohn–Rostoker Method and Green's function combined with coherent potential approximation were used to study the magnetoelectronic properties of (Al25Fe30Mn25Ni20)1−xNdx. We have obtained the value optimised of lattice parameter 2.9 Å and it is near to that obtained by experimental value using High Score programme and results XRD experimental. [ABSTRACT FROM AUTHOR]