Phase Content Research Articles

Hyaluronic acid-solid lipid nano transporter serum preparation for enhancing topical tretinoin delivery: skin safety study and visual assessment of skin.

The use of nanosized particles is becoming more popular for the topical treatment of skin conditions. In this research work, we created and investigated the effects of solid lipid nanoparticles (SLN) containing hyaluronic acid and tretinoin. Solvent emulsification diffusion method was used to prepare the SLN formulation and characterized for their physicochemical properties. Fourier transform infrared spectroscopy was used to confirm that hyaluronic acid and tretinoin were incorporated in the SLN. Furthermore, X-ray diffractogram, thermal analysis including DSC and TGA and in vitro dissolution, permeation tests were also performed along with microbial assessment. Clinical studies in human were performed to evaluate the effect of the SLN on skin wrinkles. The SLN was 750 ± 31.29nm in size, with a zeta potential of 13.07 ± 0.75mV and a narrow polydispersity index of 0.24 ± 0.12. The entrapment efficiency of tretinoin was found to be 90.07 4.79%. Clinical studies in healthy human volunteers demonstrated that 90% of the tested individuals had improved skin conditions (reduction in wrinkles), by at least one grade after 4weeks of treatment. Regarding the development on SLN, it was found that the internal phase concentration did not considerably affect the physicochemical and microbiological properties. Therefore, Hyaluronic acid has potential for the development of SLN applicable to cosmetic formulations, especially for skin. These findings show that the developed SLN have potential for use as cosmetics in the future.

Optimised phase compositions and achieved ultra-high Q×f values in Ca(2+y)Sn2Al(2+x)O(9+1.5x+y) ceramics by composition modulation

The optimization of phase compositions and microwave dielectric properties in Ca(2+y)Sn2Al(2+x)O(9+1.5x + y) (−0.2 ≤ x ≤ 0.2, −0.2 ≤ y ≤ 0.2) ceramics were investigated. The change in Al content could inhibit the SnO2 second phase of Ca2Sn2Al2O9 ceramic, and the Al deficiency in Ca2Sn2Al(2+x)O(9+1.5x) (−0.2 ≤ x < 0) ceramics contributed to the increase in the content of the CaSnO3 second phase. The enrichment of the Al content could not inhibit the CaSnO3 second phase, and the low content of the CaSnO3 second phase was obtained in Ca2Sn2Al(2+x)O(9+1.5x) (0 < x ≤ 0.2) ceramics. The high content of CaSnO3 second phase was also observed in Ca(2+y)Sn2Al2O(9+y) (0 < y ≤ 0.2) ceramics, and the enrichment of Ca induced the CaSnO3 second phase. Moreover, the slight Ca deficiency inhibited the SnO2 and CaSnO3 second phases, and the Ca2Sn2Al2O9 single-phase ceramic was obtained in Ca(2+y)Sn2Al2O(9+y) (y = −0.1). The Ca(2+y)Sn2Al(2+x)O(9+1.5x + y) (−0.2 ≤ x ≤ 0.2, −0.2 ≤ y ≤ 0.2) ceramics with a high content of CaSnO3 second phases exhibited high εr and moderate Q × f values, which were controlled by the ρrel and the content of the CaSnO3 second phase, respectively. The Q × f value was sensitive to the second phases, and Ca-deficient Ca(2+y)Sn2Al2O(9+y) (y = −0.1) ceramic with Ca2Sn2Al2O9 single-phase composition exhibited the ultra-high Q × f value (Q × f = 121818 GHz at 11.86 GHz).

Direct Synthesis of Dimethyl Carbonate from Methanol and CO2 over ZrO2 Catalysts Combined with a Dehydrating Agent and a Cocatalyst

Zirconia nanocrystals as catalysts for the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide have received significant interest recently. In this paper, three zirconia-based catalysts presenting different monoclinic and tetragonal phase contents are prepared and characterized by X-ray diffraction (XRD), N2 adsorption–desorption, transmission electron microscopy (TEM), and temperature-programmed desorption of NH3 and CO2 (NH3-TPD and CO2-TPD). The catalytic performances of these solids are evaluated in terms of DMC production. This production is low when using the bare zirconias, but it is significantly increased in the presence of 1,1,1-trimethoxymethane (TMM) playing the role of a dehydrating agent, which shifts the thermodynamic equilibrium. Moreover, the production of DMC is further improved by adding a second solid catalyst (cocatalyst), the molecular sieve 13X, to accelerate the hydration of TMM. Hence, the molecular sieve 13X plays a dual role by trapping water molecules formed by the reaction of DMC synthesis and providing strong acidic sites catalyzing TMM hydrolysis. To the best of our knowledge, the combination of two solid catalysts in the reaction medium to accelerate the water elimination to obtain higher DMC production from CO2 and methanol has never been reported.

Mechanical properties of silicone polymer with magnetic filler in magnetic field

Purpose. To investigate the change in the mechanical properties of a magnetorheological silicone elastomer consisting of a polymer filled with magnetite nanoparticles under the influence of an inhomogeneous magnetic field of an electromagnet. Methods. The experiments were carried out on a magnetic response research facility developed and manufactured independently based on known methods. The value of the deflection angle of the magnetically active receiver was determined by the optical method. Two-component silicone rubbers filled with magnetite particles were studied as samples. The manufactured samples differed in geometric dimensions, magnetic phase concentrations of 1%, 5%, 10% and 20%, and polymerization mechanism. The source of the magnetic field was electromagnets of various sizes connected to power sources. The images were captured using a Micmed 5.0 digital USB microscope.Results. The analysis of the structure of the manufactured magnetorheological silicone elastomers was carried out, as well as studies of the effect of the magnetic field strength and sample parameters on the deflection angle of the magnetically active cantilever. A theoretical interpretation of the obtained results is proposed.Conclusion. The experimental dependence of the tilt angle of a magnetically active polymer cantilever on the equilibrium position relative to the magnitude of the magnetic field strength of the electromagnet is determined. The obtained research results can be used to develop actuators and magnetoactive sensors.

Effect of MgO on solidification crystallisation behaviour of high SiO2 content MnO–SiO2–Al2O3-based inclusions in Si–Mn-killed steel

Aiming at avoiding the formation of high-hardness crystalline phase in inclusions, the effect of MgO on the solidification crystallisation behaviour of high SiO2 content MnO–SiO2–Al2O3-based inclusions was investigated. The results showed that the high SiO2 content MnO–SiO2–Al2O3 inclusions precipitated the pure SiO2 phase during the solidification process. With the increase of MgO content in inclusions, the content of the SiO2 phase decreased continuously, while the MgSiO3 phase began to precipitate and the content increased gradually. Besides, 20 wt.% MgO content inclusions first precipitated the Mg2SiO4 phase, and the MgSiO3 phase was formed in the subsequent solidification process. Thermodynamic calculation results indicated that the beginning of crystallisation temperature first decreased and then increased with the increase of MgO content in inclusions. However, the calculation results were partially different from the experiment results, because inclusions became the undercooling system during solidification and led to crystallisation hysteresis. The increase of MgO content in inclusions decreased the content of bridging oxygen and resulted in the depolymerisation of complex network structures, which promoted the crystallisation of inclusions. Moreover, the crystalline phase formed in inclusions transformed along the route of “SiO2 phase–MgSiO3 phase–Mg2SiO4 phase” with the increase of MgO content in inclusions.

A Lab-Scale Evaluation of Parameters Influencing the Mechanical Activation of Kaolin Using the Design of Experiments.

This research investigates the mechanical activation of kaolin as a supplementary cementitious material at the laboratory scale, aiming to optimize milling parameters using the response surface methodology. The study evaluated the effects of rotation speed and milling time on the amorphous phase content, the reduction in crystalline kaolinite, and impurity incorporation into the activated clay through the Rietveld method. The results demonstrated that adjusting milling parameters effectively enhanced clay activation, which is crucial for its use in low-carbon cements. High rotation speeds (300/350 rpm) and prolonged grinding times (90/120 min) in a planetary ball mill increased the pozzolanic activity by boosting the formation of amorphous phases from kaolinite and illite and reducing the particle size. However, the results evidenced that intermediate milling parameters are sufficient for reaching substantial degrees of amorphization and pozzolanic activity, avoiding the need for intensive grinding. Exceedingly aggressive milling introduced impurities like ZrO2 from the milling equipment wear, underscoring the need for a balanced approach to optimizing reactivity while minimizing impurities, energy consumption, and equipment wear. Achieving this balance is essential for efficient mechanical activation, ensuring the prepared clay's suitability as supplementary cementitious materials without excessive costs or compromised equipment integrity.

Ruthenium-doped dual-phase cobalt catalysts for enhanced electrocatalytic hydrogen evolution

Controlling the structural sensitivity and selectivity of metal catalysts in reactions, such as the hydrogen evolution reaction (HER) on cobalt crystals, remains a challenging issue in heterogeneous catalysis. In this study, we introduced a straightforward approach to tuning the phase composition of hexagonal close-packed cobalt (HCP-Co) and face-centered cubic cobalt (FCC-Co) in a core–shell Co/C catalyst through the incorporation of Ru atoms. The HER performance was evaluated by controlling the contents of HCP-Co and FCC-Co phases in the catalysts. Single-atom Ru-doped cobalt catalysts containing dual-phase HCP and FCC were prepared by a mechanical ball-milling zeolitic imidazolate framework (ZIF-67) with appropriate ruthenium chloride, followed by a pyrolysis process. The doping of Ru resulted in changes in the contents of the HCP-Co and FCC-Co phases, which significantly boosted the HER activity of the catalysts. The obtained biphasic Ru-Co/C catalyst demonstrated ultra-low HER overpotential and promising stability in alkaline and acidic media, outperforming single-phase cobalt and commercial Pt/C catalysts. Theoretical calculations revealed the synergistic catalysis effect of biphasic cobalt on HER. These findings, which indicated that significant activity dependence on the crystallographic structure, may inspire new design concepts for efficient metal electrocatalysts.

In Vitro Evaluation of Speed Sintering and Glazing Effects on the Flexural Strength and Microstructure of Highly Translucent Multilayered 5 mol% Yttria-Stabilized Zirconia.

This study aimed to investigate the impact of speed sintering and glazing on the flexural strength and microstructure of multilayered 5 mol% yttria-stabilized (5Y-) zirconia, which remains unknown. Bar-shaped specimens (N = 600) were fabricated from 5Y-zirconia (FX; Ceramill Zolid FX ML, ST; Katana STML) by cutting, polishing, sintering (conventional and speed sintering), and then glazing. A flexural strength test (n = 30/group), field emission scanning electron microscopy (FE-SEM) observation (n = 2/group), and an X-ray diffraction (XRD) study with Rietveld refinement (n = 1/group) were performed. The flexural strength was analyzed using three-way ANOVA and a post hoc Scheffé test. The grain size was analyzed using the Kruskal-Wallis H test and Bonferroni-Dunn post hoc test. Flexural strength slightly decreased in the nonglazed FX after speed sintering (p < 0.05). Glazing with and without glazing paste did not affect flexural strength at both sintering speeds (p > 0.05). Speed sintering and glazing minimally changed the Weibull modulus and phase fraction, and did not affect grain size (p > 0.05). ST had a larger grain size and lower tetragonal phase content than FX and had a lower flexural strength than FX in most groups (p < 0.05). Overall, the multilayered 5Y-zirconia is considered suitable for dental application using speed sintering and glazing.

Research on the Corrosion Resistance of Electrodeposited Ni-SiC Composites Constructed for Steel Storage Tank Application.

In this paper, the effects of the SiC phase incorporated in Ni substrate deposits on storage tank steel during electrodeposition at different current densities are explored. The microstructure, phase content, and corrosion resistance of the resulting Ni-SiC composites were investigated by scanning electron microscopy (SEM) matched with energy disperse spectroscopy (EDS), X-ray diffraction (XRD), and an electrochemical workstation, respectively. SEM micrographs and EDS results show that at 2.5 A/dm2, the composites presented a smooth and compact structure with high SiC content, while at 1.8 or 3.2 A/dm2, it became uneven and loose in structure with low SiC content. XRD patterns showed that the nickel grain size of composites firstly increased and then decreased with the growth of the current density. Notably, the Ni-SiC composite produced at 2.5 A/dm2 possessed a higher corrosion potential (-0.507 V) and lower corrosion current density (2.439 μA/cm2), illustrating that its excellent anti-corrosion ability was superior than that of other two composites. Hence, SiC co-deposited at 2.5 A/dm2 conducted as a protective barrier and inhibited the corrosion rate against a corrosion medium of Cl- and SO42- ions. In addition, the corrosion relationship illustrated that the SiC content of Ni-SiC composite firstly increased and then decreased with the growth of the current density, while the corrosion weight loss of Ni-SiC composites firstly decreased and then increased.

Optimized magnetic properties of a Terfenol-D alloy in an extended temperature range using a high magnetic field

Tb–Dy–Fe alloys are among the most suitable magnetostrictive materials for high-power transducers. Optimizing magnetic properties in an extended temperature range could ensure the stable operation of transducers. In this work, a high magnetic field is applied to the directional solidification of Tb–Dy–Fe alloys. We study the microstructure, crystallographic orientation, magnetic susceptibility, crystal structure, and magnetic domain of samples. When the content and alignment of the magnetic phase along with crystallographic orientation remain basically invariant, the magnetic susceptibility of samples increases with the magnetic flux density of the high magnetic field throughout the temperature range from 273 K to Curie temperature (T C). At 4 T, the maximum magnetic susceptibility is increased by ∼ 40% compared with the sample without a high magnetic field applied, and the advantage is maintained in the range ∼ 300 K. Analysis shows that the enhancement of magnetic susceptibility is not due to the change in crystal structure, as commonly believed, but to the highly ordered alignment of magnetic domains. This research provides a new method for improving the temperature properties of magnetic materials using a high magnetic field.

Gradient composites Al2O3-Ni obtained via the CSC technique in a magnetic field - microstructure and mechanical properties

This article presents the formation of composite microstructures by combining two established concepts: centrifugal slip casting and the utilization of a magnetic field to control the distribution of magnetic particles. The integration of these methodologies offers the potential to create zones within the composite with distinct hardness values. The study introduces a novel method for fabricating ceramic-metal composites, with a key focus on determining the feasibility of manipulating the location of the metallic phase using a magnetic field. Through this innovative approach, the research aims to produce composite hollow cylinders with a gradient distribution of metallic particles. The relative density of the composites was 97 %. The hardness values for the samples range from 970 HV to 2700 HV, displaying variability based on the metallic phase content within the material. The compressive strength for Al2O3-Ni samples was equal to 128.92 MPa. The Al2O3 grains in zone III after the sintering process have an average size of 1.27 ± 0.68 µm. The Al2O3-Ni composites indicate a smaller heat capacity of the material compared to pure Al2O3 samples.

Use of graphene (go and rGO) as a reinforcement filler to increase the beta phase in fluorinated copolymer nanocomposites

The present study aims to evaluate the influence of different types of graphene, graphene oxide (GO, synthesized by the Hummers method) and reduced graphene oxide (rGO, obtained by thermal reduction of GO) on the piezoelectric properties of composites based on PVDF copolymer. Hydrogen-fluorine interaction is expected to occur between GO or rGO and the fluorinated copolymer, increasing the β-conformation content in the polymer. The samples were prepared in the molten state at two concentrations of each charge inside a twin-screw extruder with interpenetrating screws. The characterizations of the nanocomposites were made according to their thermal and electrical properties. The effect of graphene incorporation into the P(VDF-TrFE) matrix was observed from thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results obtained indicated that the incorporation of graphene contributed to the increase in the β phase content of P(VDF-TrFE), which is indicative of the increase in its piezoelectricity.

Discovery of a new volcanic soil material, "Akahoya," as an adsorbent for bacterial and viral pathogens and its application to environmental purification.

Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including Escherichia coli, Campylobacter jejuni, Vibrio parahaemolyticus, Salmonella Enteritidis, Staphylococcus aureus, Clostridium perfringens, spores of Bacillus subtilis and Bacillus anthracis, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and Enterobacteriaceae as indicators of river contamination, as well as E. coli added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable E. coli continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of E. coli to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and Al2O3, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes.IMPORTANCEAlthough a safe and sufficient water supply is essential for the maintenance of hygienic conditions, a major challenge is to develop a comprehensive effective, sustainable, and cost-effective technological approach for the treatment and purification of contaminated water. In this study, we demonstrated that a novel volcanic soil, Akahoya, which has unlimited availability, is a highly effective adsorbent for a wide range of bacterial and viral pathogens, suggesting its potential as a sustainable resource for this purpose. It was suggested that the adsorption of microorganisms on Akahoya was mediated by phosphate groups present on the surface structures of microorganisms, which bind to the alumina component of Akahoya according to the phosphate concentration and pH of the liquid phase. The present findings highlight the exceptional ability of Akahoya to eliminate or reduce phosphate and microorganisms effectively in water purification processes, thus contributing to the development of efficient and sustainable solutions for addressing water pollution challenges.

Quantitative analysis on microstructure characteristic of pre-strained β-solidified TiAl alloy during post-heat treatment

The β/βo phase in β-solidified TiAl alloys plays a contradictory role in improving processability at high temperatures but deteriorating performance at service temperature due to its ordering transformation. After exerting its positive role during thermomechanical processing, it must be eliminated or reduced to a minimum through post-heat treatment. In this study, the microstructural evolution of the pre-strained Ti-43.24Al-8.42Nb-0.20W-0.21B-0.24Y alloy on post-heat treatment is investigated, and a quantitative relationship between βo phase content and the pre-strain is established. Due to the difference in driving force of phase transformation, with decreasing pre-strain the microstructure displays varied characteristics from a mixed structure comprising (α2+γ) lamellar colonies, γ blocks, and βo phase, to a nearly-lamellar structure after post-heat treatment at 1270 °C/4h/FC. Only if the pre-strain is less than 0.78, a refined nearly-lamellar structure can be achieved. This work provides important theoretical guidance for practical forging processing of β-solidified TiAl alloys.

Simultaneous Tailoring of Chemical Composition and Morphology Configuration in Metal Hexacyanoferrate for Ultrafast and Durable Sodium‐ion Storage

Metal hexacyanoferrates (MHCFs) with adjustable composition and open framework structures have been considered as intriguing cathode materials for sodium‐ion batteries (SIBs). Exploiting MHCFs with ultrafast and durable sodium storage capability as well as comparable capacity is always a goal that many investigators pursue, but remains challenging. Herein, simultaneous tailoring of chemical composition and morphology configuration is carried out to design a hollow monoclinic high‐entropy MHCF (HMHE‐HCF) assembled by nanocubes for the first time to realize the objective. The “cocktail effect” of high‐entropy construction, rich sodium content of monoclinic phase, and unique hollow structure endow HMHE‐HCF cathode with fast reaction kinetics and energetically stable performance during continuous charging/discharging processes. As a result, the HMHE‐HCF cathode demonstrates superior rate performance up to an ultra‐high rate of 100 C (71.1% retention to 0.1 C), and remarkable cycling stability with a capacity retention of 77.8% over 25,000 cycles at 100 C, outperforming most reported sodium‐ion cathodes. Further, the HMHE‐HCF//hard carbon full‐cell delivers capacities of 99.0 and 82.3 mAh g–1 at 0.1 C and 10 C, respectively, and retains 98.1% of the initial capacity after 1,600 cycles at 5C, demonstrating its potential application for sodium‐ion storage.

Simultaneous Tailoring of Chemical Composition and Morphology Configuration in Metal Hexacyanoferrate for Ultrafast and Durable Sodium-ion Storage.

Metal hexacyanoferrates (MHCFs) with adjustable composition and open framework structures have been considered as intriguing cathode materials for sodium-ion batteries (SIBs). Exploiting MHCFs with ultrafast and durable sodium storage capability as well as comparable capacity is always a goal that many investigators pursue, but remains challenging. Herein, simultaneous tailoring of chemical composition and morphology configuration is carried out to design a hollow monoclinic high-entropy MHCF (HMHE-HCF) assembled by nanocubes for the first time to realize the objective. The "cocktail effect" of high-entropy construction, rich sodium content of monoclinic phase, and unique hollow structure endow HMHE-HCF cathode with fast reaction kinetics and energetically stable performance during continuous charging/discharging processes. As a result, the HMHE-HCF cathode demonstrates superior rate performance up to an ultra-high rate of 100 C (71.1% retention to 0.1 C), and remarkable cycling stability with a capacity retention of 77.8% over 25,000 cycles at 100 C, outperforming most reported sodium-ion cathodes. Further, the HMHE-HCF//hard carbon full-cell delivers capacities of 99.0 and 82.3 mAh g-1 at 0.1 C and 10 C, respectively, and retains 98.1% of the initial capacity after 1,600 cycles at 5C, demonstrating its potential application for sodium-ion storage.

Effects of post-heat treatments on the microstructure and mechanical properties of Ti–6Al–4V alloy fabricated by selective laser melting

In this study, post-heat treatments were applied to Ti–6Al–4V (TC4) alloy fabricated by selective laser melting (SLM) to investigate the effects of annealing temperature (750–950 °C in 50 °C intervals) on the alloy's microstructure, residual stress and mechanical properties. The initial microstructure of as-SLMed TC4 alloy was dominated by needle-like α′ martensite with a high density of dislocations and minor β phase, resulting in high strength (1190 MPa) but limited ductility (2.2% elongation). Annealing led to the transformation of α′ martensite into α phase, with the β phase content remaining relatively stable. Increasing the annealing temperature caused the acicular martensite to evolve into bundles of coarse α laths, forming a basket-weave microstructure. Annealing at 750 °C for 2 h reduced the yield strength to 1040 MPa and improved elongation to 8.3%. Interestingly, both the strength and ductility decreased with further increases in annealing temperature. This unusual phenomenon was rarely mentioned in current literature and was considered to be associated with the abnormal variations in the Schmid factor of (0001) [11-20] slip system and the reduction of mobile dislocations within the coarsened α martensite. Additionally, annealing combined with air cooling effectively alleviated residual tensile stresses in the SLM-formed TC4 alloy.

Innovative assessment of reactivity in fly ash: The role of particle size distribution characteristics

The relationship between the intrinsic properties of seven different types of fly ash and the compressive strength of the resulting geopolymers was investigated. A comprehensive examination of the effect of chemical and mineralogical compositions, particle size distribution, on the compressive strength of the fly ash-based geopolymers were performed. Results revealed that particle size distribution had a more significant impact on reaction activity than amorphous phase content or average particle size alone. Therefore, a novel concept of 'reaction volume' based on the geopolymerization reaction mechanism was proposed, which reveals a high correlation between the reactivity of fly ash and the compressive strength of geopolymers, thereby enhancing the predictability of the process. The degree of reactivity, formulated through the integration of reaction volume and amorphous silica-aluminum content, was identified as a robust predictor of compressive strength, which can serve as a crucial tool for evaluating fly ash for the production of alkali-activated materials.

Microstructural evolution and mechanical properties of FeNiVAlx medium-entropy alloy

FeNiV alloys exhibit potential applications in magnetic, radiation-resistant, mechanical, and superconducting fields, however, the formation of the hard yet brittle sigma phase enriched with Fe and V hindered their application in extreme environments. Therefore, improving the mechanical properties of FeNiV alloys has been a crucial problem. In this study, a series of as-cast FeNiVAlx (values of x is 0, 0.1, 0.2, 0.3) medium-entropy alloys (MEAs) were fabricated by vacuum arc melting, and the evolution of microstructure and mechanical properties with different Al microalloying were investigated systematically. As the Al content increased, FeNiVAlx MEAs underwent a structural transformation from a dual-phase structure consisting of a FCC phase (46.4 %; phase content) and a sigma phase (53.6 %) at x=0 to a single BCC phase in FeNiVAl0.3, while the mechanical properties of the alloy show a decrease in strength and a significant increase in elongation. Notably, the FeNiV alloy exhibits the highest yield strength of 1851 MPa with 7.8 % ductility. In contrast, the FeNiVAl0.2 alloy demonstrated superior comprehensive compressive properties, with a high yield strength of 1255 MPa and an exceptional ductility exceeding 50 % without fracturing. The elimination of the harmful sigma phase, coupled with the formation of BCC phase, contributes to the observed decrement in strength and increment in ductility. This study elucidates the intrinsic relationship between microstructure and mechanical properties with Al contents in FeNiVAlx alloys, providing insights for the design of MEAs with excellent strength-ductility balance through microalloying.

Spectral induced polarization (SIP) measurements across a PFAS-contaminated source zone

There is a need to develop field-scale, in situ screening technologies for assessing variations in aqueous film-forming foam (AFFF) concentrations in soils at former fire training and storage sites. Field-scale Spectral Induced Polarization (SIP) geophysical measurements were acquired on a transect crossing an AFFF source zone. Soil samples were acquired to determine variations in poly- and per-fluoroalkyl substances (PFAS) concentrations in soils, characterize soil texture, and create triplicate soil columns for laboratory SIP measurements. Field and laboratory observations show that SIP measurements are sensitive to the concentration of AFFF constituents associated with soil pore surface area. The specific polarizability and the phase of the SIP measurements for the laboratory samples were linearly correlated with total soil-sorbed PFAS concentration. The phase from the field SIP measurements was highest over the location of maximum PFAS concentration measured on the laboratory samples. However, a significant correlation between field-measured phase and laboratory-measured total PFAS concentration still needs to be established. These observations, along with the demonstrated sensitivity of the SIP response to the removal of soil PFAS using a methanol wash procedure, support the case for SIP characterization of AFFF source zones.