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The structural, mechanical, thermodynamic and electronic properties of indium (In) substitution for W and Se as well as intercalating In in bulk WSe2 have been investigated by first-principles calculation. The dopant indium is more likely to substitute for W (or Se) under Se-rich (or W rich) conditions. Doping decreases the elastic modulus, hardness, Debye temperature and the minimum thermal conductivity of WSe2 (e.g., InW8Se16 has the lowest values) but effectively improves the ductile and lubrication property (e.g., InW7Se16 and InW8Se16 present a largest ductile and lubrication property, respectively). WSe2 together with the dopant are all anisotropic. InW8Se16 performs the largest degree of anisotropy among them. Indium doping cannot introduce magnetism. However, it can transform the semiconductor of pure WSe2 to semimetal. Both of the substituted structures character the p-type doping nature while the intercalated structure characters the n-type doping nature. The hybridization of W-d and Se-p electrons are the main cause of the W–Se covalent bond. New covalent bonds are formed for the In-doped structures. [ABSTRACT FROM AUTHOR]

MnO2 and CeO2 were doped to improve the corrosion resistance of CSZ (calcia-stabilized zirconia), and we studied the phase formation, mechanical properties, and corrosion resistance by molten mold flux. The volume fraction of the monoclinic phase gradually decreased as the amount of MnO2 doping increased. The splitting phenomenon of the t(101) peak was observed in 2Mn_CSZ, and in 4Mn_CSZ, it was completely split, forming a cubic phase. The relative density increased and the monoclinic phase decreased as the doping amount increased, leading to an increase in Vickers hardness and flexural strength. However, in 3Mn_CSZ and 4Mn_CSZ, where cubic phase formation occurred, the tetragonal phase decreased, leading to a reduction in these properties. MnO2-doped CSZ exhibited a larger fraction of the monoclinic phase compared to the original CSZ after the corrosion test, indicating worsened corrosion resistance. These results are attributed to the predominant presence of Mn3+ and Mn2+ forms, rather than the Mn4+ form, which has a smaller basicity difference with SiO2, and due to the low melting point. The monoclinic phase fraction decreased as the doping amount of CeO2 increased in CeO2-doped CSZ, but the rate of decrease was lower compared to MnO2-doped CSZ. The monoclinic phase decreased as the doping amount increased, but the Vickers hardness and flexural strength showed a decreasing trend due to the low relative density. The destabilization behavior of Ca in SEM-EDS images before and after corrosion was difficult to identify due to the presence of Ca in the slag, and the destabilization behavior of Ce due to slag after corrosion was not observed. In the XRD data of the specimen surface after the corrosion test, the fraction of the monoclinic phase increased compared to before the test but showed a lower monoclinic phase fraction compared to CSZ. It is believed that CeO2 has superior corrosion resistance compared to CaO because Ce predominantly exists in the form of Ce4+, which has a smaller difference in basicity within the zirconia lattice. [ABSTRACT FROM AUTHOR]

High-temperature stability, including sintering resistance and phase stability, is critical for thermal barrier coatings (TBCs) applied at ultra-high temperature over 1500 °C. In this work, we reported a high-entropy rare-earth zirconate (Y 0 2 La 0.2 Nd 0.2 Sm 0.2 Eu 0.2) 2 Zr 2 O 7 (YLNSE) synthesized by solid-state reaction method. X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectrometer (EDS) mapping results confirmed that YLNSE formed a single-phase pyrochlore structure with uniform rare earth elements distribution. YLNSE maintained more uniform microstructure, higher porosity retention, lower grain growth rate and better thermomechanical properties during sintering at 1500 °C, as the results of the ordered crystal structure and sluggish diffusion effect, indicating a better sintering resistance than conventional TBC material yttria-stabilized zirconia (YSZ). In addition, YLNSE also demonstrated high coefficient of thermal expansion (CTE, 11.04 × 10-6K-1, 25–1500 °C) and low thermal conductivity (1.95 W m-1 K-1, 1500 °C), as well as good phase stability at 1500 °C. In view of the excellent high-temperature stability of YLNSE, it is a promising candidate for ultra-high temperature TBCs. [ABSTRACT FROM AUTHOR]

The phase instability of 6–8 wt% Y 2 O 3 partially stabilized ZrO 2 (YSZ) in high temperature and molten salt corrosion environment seriously limits its application above 1200 °C. In this study, the chemical co-precipitation method prepared Yb 2 O 3 and CeO 2 co-doping YSZ (YbCeYSZ) ceramic materials to improve the above issues. It was proposed to improve the defect of high-temperature phase instability of CeO 2 -doped YSZ materials by adding Yb 2 O 3. The phase stability, thermal insulation properties, and Na 2 SO 4 + V 2 O 5 molten salt corrosion behavior of YbCeYSZ ceramic materials were studied. The results showed that 2.5 mol% Yb 2 O 3 -4 mol% CeO 2 -YSZ material (2.5Yb4CeYSZ) had no monoclinic phase (m-ZrO 2) after holding at 1500 °C for 120 h due to forming more defect clusters in the system. Meanwhile, the 2.5Yb4CeYSZ had excellent thermal insulation performance and molten salt corrosion resistance, which was attributed to the strong phonon scattering in the 2.5Yb4CeYSZ material system and the low reactivity between the stabilizer and the corrosive salt. [ABSTRACT FROM AUTHOR]

A new generation of titanium alloys with non-toxic, non-allergenic elements and lower Young's modulus (YM) have been developed, presenting modulus values close to that of bone. In titanium alloys, the value of the Young's modulus is strongly dependent on the chemical composition. Young's modulus also depends on the present phases and on the crystallographic texture related to the thermomechanical processing. A lower YM is normally attributed to the formation of the α″ phase into the β matrix, but there is no consensus for this assumption. In the present work, four alloys were designed and melted, based on the Ti-Nb-Mo-Zr system and heat-treated to favor the formation of the β phase. The alloys were produced by arc melting under argon atmosphere and heat-treated at 1000 °C for 24 h under high vacuum, being subsequently quenched in water to room temperature. Alloys were then characterized by optical microscopy (OM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Young's modulus was determined by the impulse excitation technique and Vickers microhardness. The purpose of the study was to define an optimal chemical composition for the further production on a semi-industrial scale of a new Ti-Nb-Mo-Zr alloy for orthopedic implant manufacturing. The results showed that all of the four studied alloys are potential candidates for biomedical applications. Among them, the Ti-24Nb-4Mo-6Zr alloy has the lowest Young's modulus and the highest microhardness. So, this alloy presents the highest HV/YM ratio, which is a key indicator in order to evaluate the mechanical performance of metallic biomaterials for orthopedic implants. [ABSTRACT FROM AUTHOR]

First-principles studies on phase stability and resistance with respect to the segregation of austenitic and martensitic phases of Ni2 – xCoxMn1 + yZ1 – y Heusler alloys (x = 0, 0.25, 0.5 and y = 0, 0.25, 0.5, 0.75; Z = Ga, In, Sb, Sn) with different types of magnetic ordering. Among all the considered compounds, the stability has been demonstrated only by the Ni1.5Co0.5MnGa and Ni2MnGa alloys in the cubic and tetragonal structures having a ferromagnetic ordering, respectively, as well as by Ni2Mn2 in the tetragonal structure with a staggered and layer-by-layer AFM ordering. For the case of these compositions, the presence of zero energy of the convex hull, as well as the absence of reactions with positive decomposition energy has been shown. The remaining compounds appear to be metastable, both owing to the presence of stable reactions with negative decomposition energy, and decomposition reactions with positive decomposition energy. The number of decomposition reactions exhibits an increase with increasing chemical disorder, i.e., with deviations from stoichiometry. [ABSTRACT FROM AUTHOR]

In this study, microstructure and phase transformation behavior in Fe20Co20Ni20Cr20B20-xSix alloys prepared by the mechanical alloying (MA) method were investigated by X-ray diffraction (XRD) measurements, scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry (DSC). The Fe20Co20Ni20Cr20B20-xSix alloys prepared by the melt-spinning method were composed of FCC and compounds, and the FCC and BCC phases predicted by the valance electron concentration parameter were not formed. However, alloy powders prepared by the MA method were revealed to be composed of the FCC and BCC phases. Small amounts of unreacted pure B and Si particles were observed in alloy powders with high and low B content, respectively. XRD and DSC measurements revealed that the BCC phase in MA powder disappeared, and compounds were formed by heating up to 700°C. Especially the compound formation temperature was higher than that of the same alloy prepared by the melt-spinning method, suggesting that the thermal stability of the alloy powders prepared by the MA method was higher than that of the alloy ribbons prepared by the melt-spinning method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Roseolumiflavin is a deep red microcrystalline derivative of isoalloxazine that exhibits a weak photophysical activity in the solid state. In aqueous as well as in acidic solution of formic or acetic acid, respectively, it tends to form solvates. Herein, we present a set of binary and ternary roseolumiflavin solvates including one hydrate and a solvate hydrate. The impact of the solvent on solvate formation along with an in-depth structural analysis was investigated. Calculations of the lattice energies provide insight into the phase stability of the evaluated systems showing an energetic benefit for all solvates with values up to −395.82 kJ/mol. The total interaction energies between molecules calculated via Crystal Explorer further identified cofacial π···π stacks to be the most strongly bonding fragments in the crystal lattices for all systems except the formic acid solvate, followed by remarkably weaker hydrogen-bonded arrangements. The energetic contributions of single intermolecular interactions within the fragments are evaluated by an atoms-in-molecules approach. It is shown that physicochemical properties, such as thermal stability, can be tuned depending on the incorporated solvent molecules despite a high decomposition temperature of the chromophore. [ABSTRACT FROM AUTHOR]

Alloying plays an important role in controlling the phase stability, mechanical properties, and deformation behavior of ordered intermetallic compounds. In this study, the effects of 3d, 4d, and 5d transition elements on site preference, elastic properties, ideal shear strength, and planar fault energies of L12 Co–Ti-based alloys were systematically investigated by using first-principles calculations. The calculated transfer energy and formation enthalpy indicate that Sc, V, Cr, Y, Zr, Nb, Mo, W, Hf, Ta, and W tend to occupy the Ti site, which reduce the structural stability of L12-Co3Ti. The elastic moduli and ideal shear strength of L12-Co3(Ti,M) increase with average electron density. The electron localization function (ELF) analysis reveals that the Co–M bonds have a stronger covalent character than the Co–Ti bond, which plays an important role in the strengthening of the alloys. The ratio of superlattice intrinsic stacking fault (SISF) to anti-phase boundary (APB) energy of L12-Co3(Ti,M) decreases with increasing atomic number of alloying elements in each period in the range of studied elements, which tends to change the deformation mode from the APB-favored to SISF-favored ones. The APB anisotropy ratio of L12-Co3(Ti,M) decreases with increasing atomic number of alloying elements in each period, which enhances the yield strength anomaly. This study not only sheds insight into the fundamental understanding of phase stability and mechanical behavior of multicomponent L12 compounds, but also provides useful guidelines for designing novel L12-stregnthened Co-based superalloys with superior mechanical properties.

We report on the synthesis and structural characterization of a new naproxen salt. In-situ heating X-ray diffraction experiment allows us to determine the phase stability of the various polymorphic phases. Slow heating rate and repetitive scans strategy were essential to probe all phases in presence. Contrary to previously reported absence of polymorphic forms for naproxen salt, this new salt exhibits one metastable dihydrate form and five anhydrous phases. The crystal structures of all phases were determined using the in-situ X-ray powder diffraction data.

The high-temperature phase stability of the NbCr2 Laves phase has not yet been established beyond disagreement. The well accepted C14 phase field has been eliminated from the Nb-Cr phase diagram in a recent study that claimed that the NbCr2 alloy shows the C15 structure up to melting. The present study was conducted to address these ambiguities. The experimental investigations show the presence of C14, C15, and C36 structures in the as-cast alloy. Differential scanning calorimetry studies of the as-cast alloy show the transformation of the eutectic mixture of bcc + NbCr2 to single-phase NbCr2 at 1338 K. An in-situ X-ray diffraction (XRD) study of as-cast alloy shows a phase transformation of C36 → C14 below 1273 K. Density functional theory (DFT) calculations confirm two phase transformations: (a) a metastable transformation of C36 → C14 at 783 K and (b) an equilibrium transformation of C15 → C14 at 1971 K, which was validated by high temperature DTA and TEM studies. Further, extended DFT calculations on supercells with four compositions of NbCr1.9, NbCr2, NbCr2.1, and NbCr2.2 also corroborated the presence of the C14 phase, and consequently, the Nb-Cr phase diagram is modified. This finding resolves the controversy regarding the existence of an equilibrium C14 phase field before melting.

This study aims to investigate the high-temperature phase stability and hot corrosion behavior of zirconia with triple doping of Sc3+, Ce4+ and Y3+ ions. FESEM result shows that the mean particle size of ScCeYSZ nanoparticles was 80–90 nm. Next, optimal samples regarding the highest high-temperature phase stability (1.9%Sc8.3%Ce1.8%YSZ, 1.1%Sc9.0%Ce1.8%YSZ and 0.5%Sc9.6%Ce1.8%YSZ) were consolidated at 1550 °C for 15 min via the spark plasma sintering (SPS) method. A hot corrosion test was done in the presence of 45%Na2SO4+%55V2O5 salts on three samples at 900 °C for 2 h. Also, the results of hot corrosion were compared with ceramic resulting from the nanostructured YSZ bulk sample (nanoYSZ).Based on the X-ray diffraction results, the formation of the non-transformable tetragonal phase is confirmed in the synthesized nanopowders. Also, the phase and microstructural results after hot corrosion of sintered samples show the formation of a monoclinic phase and destructive YVO4 crystals and quasi-cubic CeO2 crystals on the surface of sintered samples. The results indicated that the sample containing 1.8% scandia, 8.3% ceria, and 1.9% yttria had the highest phase stability and hot corrosion resistance (low monoclinic percentage and low leaching of stabilizer elements of Sc3+:Ce4+:Y3+ from zirconia lattice and low depth of molten salt).

The mismatch of thermal expansion coefficient (CTE) between thermal barrier coatings (TBCs) and environmental barrier coatings (EBCs) is the key factor that affects the durability of T/EBCs in aero-engine environments. To alleviate the CTE mismatch, the novel TBC materials with relatively low CTE are needed. In this study, Lu 4 Hf 3 O 12 with δ-phase rhombohedral structure was synthesized by solid-state reaction using Lu 2 O 3 and HfO 2 as the raw materials. Lu 4 Hf 3 O 12 ceramics exhibited outstanding phase stability up to 1600 °C and comparable mechanical properties to 8 wt% Y 2 O 3 stabilized ZrO 2 (8YSZ) as well as great resistance against water-vapour/oxygen corrosion. Additionally, it possessed the thermal conductivity of 1.20 W/m·K at 1000 °C, about 43% lower compared to traditional 8YSZ material (2.1–2.22 W/m·K), and coefficient of thermal expansion (CTE) of 8.46 × 10−6 K−1 (10.38 × 10−6 K−1 for 8YSZ). These results preliminarily reveal that Lu 4 Hf 3 O 12 could be considered as a potential material for thermal insulation top-coat in the field of T/EBCs. [ABSTRACT FROM AUTHOR]

By combining isoquinoline‐5‐carboxilic acid with Cu(II) ions under several different conditions, we were able to obtain novel metallorganic materials, among which two 2D coordination polymers, CP 1 and CP 2 which were also characterized by SC‐XRD. Ratio of solvents (EtOH : DMF) in the mixture employed during their synthesis has a marked effect in selecting the formation of one species or the other, which basically differ in the coordination at the Cu(II) center due to k1/k2 denticity of the carboxylate ligands. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbX3 (X = I, Br, Cl or their mixtures) perovskites attract enormous attention in recent years due to their excellent optoelectronic properties, outstanding thermal/light stability, and wide range of applications in electronic devices. Encouragingly, the reported power conversion efficiency of CsPbX3 perovskite solar cells (PSCs) rockets up from 2.9% in 2015 to the present 21.0%. In order to further promote the performance of CsPbX3 PSCs toward the Shockley–Queisser efficiency limit, it is important to optimize the quality of perovskite films by crystallization kinetics modulation and defect suppression. In this review, first, some fundamental information about all‐inorganic CsPbX3 perovskites is briefly introduced, including the crystallization mechanism, growth mode, crystal structure, and phase stability as well as possible defects and their effects on device performance. Second, the recent exciting progress of the crystallization modulation strategies for high‐quality CsPbX3 films is summarized and discussed in detail. The advantages of different strategies, including annealing engineering, solvent engineering, precursor engineering, composition engineering, and interface engineering, are highlighted. Finally, methods for improving the efficiency of inorganic PSCs are discussed, and the future development prospects of inorganic PSCs are also outlined. [ABSTRACT FROM AUTHOR]

The equilibrium FeNi alloy prefers face centered cubic (fcc) phase whereas the formation of metastable phases through certain low‐temperature synthesis methods is obscure. FeNi alloy exhibiting nonequilibrium body centered cubic (bcc) structure beyond 5 at% Ni is obtained through chemical reduction at 453 K with noticeable lattice shrinkage. Positron lifetime analysis and Doppler broadening spectroscopy are employed to probe the correlation between defects and phase stability. The mean lifetime of the chemically synthesized alloys is larger than 300 ps, implying an average of 7‐vacancy cluster. The modified two‐state trapping model reveals defect concentration in the range of 1022 m−3$\left(10\right)^{22} \left(\text{ m}\right)^{- 3}$, on par with irradiated alloys. Significant deviation in the high‐momentum component between the bulk and chemically synthesized samples is correlated to the changes in 3d electrons. The Fe and FeNi alloy uncover significant contraction in d‐band of Fe which facilitates bcc phase stabilization above 5 at% Ni through cluster vacancy formation. [ABSTRACT FROM AUTHOR]

CaMnO3 is a promising starting point for the search of perovskites which are suitable as electrode materials for the hydrogen evolution reaction (HER). In a previous theoretical study [Phys. Status Solidi B 2022, 260, 2200427], it was established that the global hybrid functional PW1PW is well suited to obtain structural, energetic, and electronic bulk properties. Herein, the focus is extended to surface properties of CaMnO3. All symmetry‐inequivalent low‐index surfaces of CaMnO3 are investigated with PW1PW. Based on the experience with polar surfaces, it is decided to employ stoichiometric and symmetric models, in some cases with Schottky defects. From the calculated surface energies, the crystal morphologies are predicted based on the Gibbs–Wulff theorem. The (101), (100), (011), (001), and (010) surfaces (space group no. 62) and the (010), (110), (011), and (101) surfaces (space group no. 20) dominate the surfaces of respective single crystals and should be considered in future theoretical calculations of the HER. Furthermore, it is found that the modification with space group no. 20 is significantly more stable than space group no. 62 for nanoparticles with a diameter below 10 nm. [ABSTRACT FROM AUTHOR]

In this study, the structural, electronic, magnetic, mechanical, and dynamical properties of the new d0–d half‐Heusler (d0–d HH) KCrSb compound are investigated using spin‐polarized first‐principles calculations. Two distinct approaches are used: generalized gradient approximation (GGA) and the modified version of the Becke–Johnson GGA (mBJ–GGA). The stability investigations reveal an energetically, mechanically, and dynamically stable d0–d HH KCrSb. The magneto‐electronic research shows a stable compound in the ferromagnetic state with a half‐metallic behavior. The half‐metallic gap is 0.9 and 1.2 eV from GGA and mBJ‐GGA, respectively. It is found that the magnetic moment of the compound is an integer and follows the Slater–Pauling rule MT=(ZT−8)$M_{\text{T}} = \left(\right. Z_{\text{T}} - 8 \left.\right) \left(\mu\right)_{\text{B}}$μB. So, the d0–d HH KCrSb compound is a potential candidate for spintronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Both numerical and experimental studies of the stability and electronic properties of barium–sodium metaborate Ba2Na3(B3O6)2F (P63/m) at pressures up to 10 GPa have been carried out. Electronic-structure calculations with HSE06 hybrid functional showed that Ba2Na3(B3O6)2F has an indirect band gap of 6.289 eV. A numerical study revealed the decomposition of Ba2Na3(B3O6)2F into the BaB2O4, NaBO2, and NaF phases above 3.4 GPa at 300 K. Subsequent high-pressure high-temperature experiments performed using 'Discoverer-1500' DIA-type apparatus at pressures of 3 and 6 GPa and temperature of 1173 K confirmed the stability of Ba2Na3(B3O6)2F at 3 GPa and its decomposition into BaB2O4, NaBO2, and NaF at 6 GPa, which was verified by energy-dispersive X-ray analysis and Raman spectroscopy. The observed Raman bands of the Ba2Na3(B3O6)2F phase were assigned by comparing the experimental and calculated spectra. The experimental Raman spectra of decomposition reaction products obtained at 6 GPa suggest the origin of a new high-pressure modification of barium metaborate BaB2O4. [ABSTRACT FROM AUTHOR]

CaMnO3 is a promising starting point for the search of perovskites which are suitable as electrode materials for the hydrogen evolution reaction (HER). In a previous theoretical study [Phys. Status Solidi B 2022, 260, 2200427], it was established that the global hybrid functional PW1PW is well suited to obtain structural, energetic, and electronic bulk properties. Herein, the focus is extended to surface properties of CaMnO3. All symmetry‐inequivalent low‐index surfaces of CaMnO3 are investigated with PW1PW. Based on the experience with polar surfaces, it is decided to employ stoichiometric and symmetric models, in some cases with Schottky defects. From the calculated surface energies, the crystal morphologies are predicted based on the Gibbs–Wulff theorem. The (101), (100), (011), (001), and (010) surfaces (space group no. 62) and the (010), (110), (011), and (101) surfaces (space group no. 20) dominate the surfaces of respective single crystals and should be considered in future theoretical calculations of the HER. Furthermore, it is found that the modification with space group no. 20 is significantly more stable than space group no. 62 for nanoparticles with a diameter below 10 nm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai University of Engineering Science / Shanghai Gongcheng Jishu Daxue Xuebao is the property of Journal of Shanghai University of Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alloys are beneficial in numerous applications since they combine the desirable properties of different metals. In this regard, Pt/Pd alloys have been investigated as a replacement for Pt, which is the standard catalyst used in various catalytic processes. However, there are still gaps in our understanding of the structural, mechanical, and thermodynamic properties of Pt/Pd alloys. This study was conducted using density functional theory (DFT) calculations to investigate the electronic, elasticity, mechanical, and thermodynamic properties of Pt/Pd alloys and compared them to pristine Pt and Pd structures. The results indicate that the considered Pt/Pd alloy structures, PtPd3, PtPd, Pt3Pd, and Pt7Pd, are energetically favourable based on their formation energies. These structures also satisfy Born's stability criteria and are elastically stable. The phonon density of states showed that the considered Pt/Pd alloy structures are dynamically stable, with no imaginary modes present. Additionally, the Pt atom dominates at lower frequencies, while the Pd atom dominates at higher frequencies, as seen in the phonon band structure. The electronic density of states revealed that the considered Pt/Pd alloy structures have a metallic character and are non-magnetic. These findings contribute to a better understanding of the properties and stability of Pt/Pd alloy structures that are relevant in various fields, including materials science and catalysis. [ABSTRACT FROM AUTHOR]

The possibility of altering the phase equilibria of multicomponent oxide systems through precise control of configurational entropy has opened a platform with unlimited possibilities to fine-tune material properties. The current work is aimed at tailoring the mechanical and thermal properties of (MgNiCoCuZn)O by an intelligent design of constituent phase structure resulting from controlled cooling from the stabilization temperature. Based on the cooling rates, the amount of CuO nucleation was found to vary between 5.4 and 12.3 wt%, along with a corresponding decrease in Cu2+ content in the matrix. It was observed that with the decrease in Cu2+ ion concentration in the matrix, the Young's modulus and hardness increased by 33% and 26%, respectively, along with a corresponding decrease in the coefficient of thermal expansion by 15%. Similarly, an increased nucleation of CuO precipitates led to the improvement of fracture toughness of the material by 15%, while its thermal conductivity remained unaltered. [Display omitted] [ABSTRACT FROM AUTHOR]

The Nb–16Si–18Ti–xB (at%, similarly hereinafter, x = 0, 1, 2, 3) alloys were prepared by arc melting in a water-cooled copper crucible. The influences of B addition on their microstructures and properties were based on the data of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and electronic universal material testing machine. It is found that the addition of B promotes the formation of α-Nb5Si3 phase and suppresses the formation of Nb3Si phase. B addition also tends Nb–16Si–18Ti alloy to form the hypereutectic structures. The content of silicide phases shows a trend of firstly decreasing and then increasing in Nb–16Si–18Ti–xB (x = 0, 1, 2, 3) alloys. The size of Nb solid solution (Nbss) phase increases in Nb–16Si–18Ti–xB (x = 0, 1, 2, 3) alloys after heat treatment at 1523 K for 10 h. The room temperature compression strength of Nb–16Si–18Ti alloy increases firstly and then decreases with B addition. The high-temperature compression strength of Nb–16Si–18Ti alloy decreases firstly and then increases with B addition. It is found that the volume and size of silicide phases have a synergistic effect on the compression strength of Nb–Ti–Si-based alloys. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The total energies of a number of Ti–Si intermetallic phases are calculated by the projector augmented-wave method. It is shown that the formation enthalpies of Ti5Si3 and TiSi are almost equal. The peculiarities of the density of electronic states of the considered titanium silicides and its evolution with increasing silicon content are discussed. The formation energies of doped titanium silicides Ti5Si3 and TiSi are calculated depending on the position of the impurity on different sublattices. It is established that the elements of the 3d-period prefer to replace titanium in Ti5Si3, while the elements of the second half of the 3d‑period substitute silicon in TiSi. The effect of impurities on the relative stability of compounds is studied. It is shown that almost all the considered elements except Cu, Zn, Al, and Ga increase the stability of the Ti5Si3 phase with respect to TiSi. The obtained results agree with the available experimental data. [ABSTRACT FROM AUTHOR]

The phase stability, mechanical properties, and functional properties of Ti–5.5Al–11.8[Mo]eq alloys are focused on in this study by substituting 3d transition metal elements (V, Cr, Co, and Ni) for Mo as β-stabilizers to achieve similar β phase stability and room temperature (RT) superelasticity. The ternary alloy systems with the equivalent chemical compositions of Ti–5.5Al–17.7V, Ti–5.5Al–9.5Cr, Ti–5.5Al–7.0Co, and Ti–5.5Al–9.5Ni (mass%) alloys were selected as the target materials based on the Mo equivalent formula, which has been applied for the Ti–5.5Al–11.8Mo alloy in the literature. The fundamental mechanical properties and functionalities of the selected alloys were examined. The β phase was stabilized at RT in all alloys except for the Ti–Al–V alloy. Among all alloys, the Ti–Al–Ni alloy exhibited superelasticity in the cyclic loading–unloading tensile tests at RT. As a result, similar to the Ti–5.5Al–11.8Mo mother alloy, by utilizing the Mo equivalent formula to substitute 3d transition metal elements for Mo, a RT superelasticity was successfully imposed. [ABSTRACT FROM AUTHOR]

A series of 16 mol% CeO 2 -2 mol% Re 2 O 3 co-stabilised zirconia (ZrO 2) (16Ce4ReSZ, Re Eu, Gd, Dy, Y, Er, Yb) ceramic materials were synthesised using a chemical coprecipitation– high-temperature roasting method. Their phase structure, high-temperature phase stability, mechanical properties, thermal conductivity and coefficient of thermal expansion (CTE) were investigated. The results show that the ZrO 2 tetragonal phase co-stabilised by CeO 2 and Re3+ with a smaller radius has better stability. The 16Ce4ReSZ (Re Dy, Y, Er, Yb) materials have high fracture toughnesses, low thermal conductivities, and high CTE values. As the radius of the Re3+ ions decreases, the lattice energy increased, while the lattice distortion decreases, the CTE decreases slightly and the thermal conductivity of the material increases slightly. Owing to the high phase stability of 16Ce4YbSZ, its mechanical properties are best after 100 h of sintering at 1400 °C. [ABSTRACT FROM AUTHOR]

Formamidinium lead triiodide (FAPbI3) with an optimal bandgap of 1.48 eV and superior thermal stability is regarded as one of the most promising perovskite‐based materials for the application in efficient single‐junction solar cells. However, the metastable properties of FAPbI3 due to phase transition from photoactive α phase into an undesired nonperovskite δ phase in ambient conditions become the major factors limiting its further development. Challenges remain in stabilizing α phase structure and preparing phase‐pure α‐FAPbI3 films for high‐efficiency and stable perovskite solar cells (PSCs) devices. Herein, the recent research progress on the strategies is reviewed to fabricate phase‐pure α‐FAPbI3 perovskite and the advances in their photovoltaic application. The physical parameters affecting the phase instability of intrinsic FAPbI3 are first discussed, followed by various methodologies for regulating phase transition behavior, such as additive engineering, solvent optimization, dimensionality engineering, and fabrication techniques. Finally, the fundamental challenges of preparing efficient α‐FAPbI3 PSCs are discussed, and the perspectives on the further development of high‐quality phase‐pure α‐FAPbI3 for reliable PSCs are proposed. [ABSTRACT FROM AUTHOR]

It has been reported that severely cold worked Fe-24.6Ni-5.8Al-0.4C (mass%) had a yield strength of 2 GPa and a fiacture elongation of 20%, in which huge amount of Liiders-type deformation was observed. In the present article, we summarize the reports for high-strength Fe-Ni-Al-C, Fe-Mn, Fe-Cr-Ni and Fe-Ni-Mn base steels with the Liiders-type deformation so far, and provide our latest data on the effects of alloying elements and the cold-rolling reduction on the microstructure and mechanical properties of cold-rolled Fe-Ni-Al-C alloys. Previous reports imply that the phase stability of y phase affects the size of Lüders elongation, while the strategies to control the microstructure to achieve high strength and high ductility are currently unknown. Our latest study also shows that the y-phase stability affects the Lüders strain. In addition, it is confirmed that severe cold rolling by 80% enables the prolonged Lüders strain as much as 25% in nominal strain. This prolonged Lüders strain is achieved by multiple propagation of Lüders-type bands. [ABSTRACT FROM AUTHOR]

The standard heat treatment of PH 13-8 Mo maraging steels consists of solution annealing and subsequent aging. Herein, it is investigated how an additional intercritical annealing step prior to aging affects the microstructure, and, consequently, the mechanical properties of a PH 13-8 Mo maraging steel. In situ techniques by means of high-temperature electron backscatter diffraction and high-temperature X-ray diffraction are applied to study the microstructural changes during intercritical annealing and subsequent aging. In addition, highresolution investigation methods, such as transmission electron microscopy and atom probe tomography supplemented by transmission Kikuchi diffraction, are used for an in-depth characterization of the microstructure. The results reveal that a diffusion-controlled martensite to austenite transformation accompanied by partitioning of the substitutional atoms Cr, Ni, and Mo takes place during intercritical annealing. As a result of partitioning during intercritical annealing, an inhomogeneous distribution of Ni remains in the microstructure after the martensitic transformation. Consequently, the formation of reverted austenite is facilitated during subsequent aging due to existing Ni-enriched zones in martensite. Since the fracture toughness is significantly enhanced compared to the standard heat treatment, it is suggested that this improvement is related to the increased phase fraction of reverted austenite. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the influence of grain growth during heat treatment on the phase stability of AZO: A 2 Zr 2 O 7 compounds at 1300°C. To this end, three cations of La3+, Gd3+, and Yb3+ (corresponding to large, medium and small cations, respectively) were placed in the A-site of the AZO compounds through co-precipitation–calcination technique at 1000°C for 3 h to achieve LaZO: La 2 Zr 2 O 7 , GdZO: Gd 2 Zr 2 O 7 , and YbZO: Yb 2 Zr 2 O 7 , respectively. The phase stability of LaZO, GdZO, and YbZO was assessed under 50 h of heat treatment at 1300°C. Characterization techniques such as conventional and high-temperature XRD, Raman and Fourier transform infrared (FTIR) spectroscopies, simultaneous thermal analysis (DTA/TG), and field-emission scanning electron microscopy (FESEM) were employed to assess the synthesized compounds. FESEM results of LaZO, GdZO and YbZO calcinated powders indicated orderly particles, uniform in shape and size, with a relative tendency of agglomeration and with an average particle size of less than ∼100 nm. XRD results of LaZO and YbZO powders after calcination indicated the formation of pyrochlore and defect fluorite structures, respectively. The placement of Gd3+ (GdZO) led to the formation of a dual pyrochlore-defect fluorite structure. The current research also indicated an enhancement in the tendency to form pyrochlore structure in GdZO and YbZO compounds along with the growth of the grains after 20 (mean grain size of ∼250 nm) and 50 h (mean grain size of ∼800 nm) of exposure to the temperature of 1300°C, respectively. [ABSTRACT FROM AUTHOR]

Phase stability and equilibrium calculations are very significant in the process industries, ranging from process simulation, equipment design, operation and design. These problems involve several systems of complex and nonlinear equations, which are mathematically challenging. An alternative solution is formulating the problems into a global optimisation problem. A robust and reliable optimisation technique is required to solve these global optimisation problems. In this study, two recently developed stochastic global optimisation algorithms, POA and GTO were applied to phase stability and equilibrium problems. The need to enhance their performance necessitated the development of two modified algorithms, PGOA1 and PGOA2, which are the hybridisation of POA and GTO. All the algorithms' abilities were explored for solving computationally challenging and multidimensional phase stability and equilibrium problems, and their performances were compared. The implementation of POA and GTO was good in solving most problems, though GTO slightly outperformed POA. The hybridisation of both to develop PGOA1 and PGOA2 was worthwhile as both outperformed the POA and GTO. PGOA2 is more robust and reliable in solving phase stability and equilibrium, and its performance superseded the performances of the other algorithms. • Pelican and Gorilla troops algorithms applied to phase problems. • Phase stability and equilibrium for non-reactive and reactive benchmark problems. • Hybrid of Pelican and Gorilla troop algorithms outperformed the parent algorithms. • The inclusion of a local optimizer improved the algorithms. [ABSTRACT FROM AUTHOR]

Ta2O5-Y2O3 co-doped ZrO2 (TYSZ) powders were prepared by high-temperature solid-phase synthesis, and a TYSZ coating was prepared by atmospheric plasma spraying (APS). The phase structures, coefficient of thermal expansion (CTE), and thermal conductivity of the TYSZ and YSZ coating were studied. Thermal cycling was performed at 1400 °C to evaluate the feasibility of TYSZ as an optimal ceramic material for next-generation gas-turbine thermal barrier coatings. The results indicate that the sintered agglomerated TYSZ powders are regular solid spheres with uniform particle size and good flow performance, which meet the requirements of the APS. The TYSZ coating had a typical layered structure, and the coating bond strength was 27.5 MPa. In contrast to the stable t phase of the powder, the TYSZ coating has a cubic phase due to oxygen defects caused by oxygen escaping during spraying. After high-temperature heat treatment (>1300 °C), the cubic phase of the TYSZ coating reverted to the t phase. Due to the specially designed substitution defects, the coefficient of thermal expansion of TYSZ is slightly lower than that of YSZ, and the thermal conductivity is much lower than that of the YSZ coating. After 84 cycles, spalling and cracking occurred in the TYSZ coating near the bond coat and ceramic interface. The mismatch in the coefficient of thermal expansion between the TYSZ coating and the substrate appears to be the primary reason for the coating failure. [ABSTRACT FROM AUTHOR]

In a previous theoretical study [B. Grimm and T. Bredow, Oxygen Defect Formation Thermodynamics of CaMnO3: A Closer Look. Phys. Status Solidi B 2022, https://doi.org/10.1002/pssb.202200427], the structural, thermodynamic, and electronic properties of CaMnO3 have been studied. The present study increases the range of compounds to ternary perovskites in a search for suitable anode materials for high‐temperature water electrolysis. (A,A′)(B,B′)O3 compounds containing the abundant elements A = Mg,Ca,Sr and B = Ti,Mn,Cr,Fe,Mo are studied theoretically on hybrid density functional theory level. Criteria for a suitable electrode material are low‐oxygen defect formation energy and high reaction energy for decomposition into other phases. Based on these criteria, the most suitable ABO3 perovskites are chosen as starting points to create stable mixed compounds. The compound Ca0.5Sr0.5Fe0.25Mn0.75O3−δ is found to be the optimal choice as electrode material, with an oxygen defect concentration of at least δ = 0.1875 present at 520 K and highly endothermic decomposition reactions. [ABSTRACT FROM AUTHOR]

In this study, for the concentrations of x=0.0, 0.25, 0.5, 0.75 and 1.0, the calculations of the physical properties of GaP1–xNx mixed alloys are presented. To perform these calculations, we employ WIEN2k computational code based on the approach of full-potential linearized augmented plane wave plus local orbital FP(L(APW+lo)), which is framed within density functional theory. At first, at the level of the WC-GGA scheme, the phase stability of the GaP1–xNx alloys in their sodium chloride (B1), zinc-blende (B3) and wurtzite (B4) structures were analysed. The analysis of our results shows that GaP, GaP0.75N0.25, GaP0.5N0.5 and GaP0.25N0.75 are stable in B3 crystal structure, whereas GaN is found to be stabilized in wurtzite structure. Moreover, for each concentration, the pressure-induced phase transition of B3 and B4 structures to B1 structure is also explored. On the other hand, the calculations of the band structures show changeover of indirect band gap energy for GaP with energy gap 2.23 eV to direct band nature for GaN with band gap energy 3.183 eV. Likewise, the optical properties are explored for the energy range of 0.0–40 eV. The investigations of the thermodynamic properties, for example, entropy, Debye temperature, specific heat are carried out at the level of the 'quasi-harmonic Debye model'. Moreover, the effect on the thermodynamic properties by temperature and pressure is also predicted. The results obtained for band gap energy as well as the optical absorption coefficients endorse that the investigated compositions of the alloys are very right for infrared to visible region optoelectronic applications. [ABSTRACT FROM AUTHOR]

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