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Hastelloy X (HX) is used in a wide range of aerospace applications due to its excellent high-temperature properties, Dynamic strain aging (DSA) and Dynamic recrystallization (DRX) are of great interest as they affect the mechanical behavior at high temperatures. In this study, the serrated flow behavior of highly textured Hastelloy X fabricated by laser powder bed fusion (LPBF) is investigated during uniaxial straining over a wide range of temperatures (20–800 °C) and strain rates (5×10−2 s−1 to 5×10−4 s−1). The alloy exhibits different types of tensile serrated flow in the temperature range of 200–600 °C. The alloy has been shown to have a very good tensile flow behavior. The presence of the Portevin-Le Chatelier effect (PLC) due to dynamic strain failure was observed at temperatures lower than 600 °C, respectively, with an average activation energy value of 45 kJ/mol calculated using the quasi-static aging (McCormick) model, and an average activation energy value calculated using the solute resistance (Cottrell) model of 41.8 kJ/mol, which is significantly lower than the 80–130 kJ/mol of conventionally fabricated HX. The effects of temperature and strain rate on fracture morphology and microstructure were analyzed by SEM, and the dynamic recrystallization behavior and nucleation mechanism were characterized by electron backscatter diffraction (EBSD). The changes in the content of recrystallized texture Cube and deformed texture Goss at different deformation temperatures are explained, and the dynamic recrystallization mode changes, from continuous dynamic recrystallization (CDRX) to discontinuous dynamic recrystallization (DDRX) as the deformation temperature increase. Verification of the different DRX mechanisms contributes to a comprehensive understanding of the microstructural evolution of the hot deformation of HX fabricated by LPBF. • The highly textured Hastelloy X was fabricated by laser powder bed fusion. • Influence of temperature and strain rate on serrated flow behavior of HX were investigated. • EBSD was utilized to determine the dynamic recrystallization mechanism and changes in texture content. [ABSTRACT FROM AUTHOR]

With an emphasis on the development of machine learning-based constitutive modeling approaches, the state of constitutive modeling techniques and applications for metals and alloys was examined. This study explored three distinct methods of constitutive modeling: phenomenological constitutive models, physical-based constitutive models, and machine learning-based constitutive models. There was discussion of the benefits and drawbacks of three constitutive models. Analyzed and reviewed were the corresponding uses of neural networks in phenomenological models and physics-based constitutive models. In-depth analysis was conducted on the development of machine learning-based constitutive modeling methods and their uses, particularly the application of machine learning in combination with finite elements (FE). The trends of constitutive modeling approaches are finally covered after going over and summarizing the advantages and current trends of employing machine learning modeling techniques in place of numerical constitutive modeling techniques. The review may offer a more comprehensive reference for the advancement of constitutive modeling techniques for metallic materials research. [ABSTRACT FROM AUTHOR]

A method for predicting fatigue life using damage variables coupled with multi-modal microstructure damage evolution was proposed after analyzing the weights of the multi-modal microstructure of directionally solidified Ni-based superalloys DZ125 in this paper. Mechanical property tests and metallographic observation tests were carried out, and the microstructure weights of the superalloys were quantified using principal component analysis (PCA) and entropy-based inter-criteria correlation (CRITIC) weight analysis. The relationship between mechanical properties and multi-modal microstructures of the superalloys was analyzed, and fatigue life was predicted using damage variables coupled with multi-modal microstructure damage evolution. The weights of multi-modal microstructures of Ni-based superalloys and the influence of multi-modal microstructural damage evolution on mechanical properties were quantified by taking into account the interactions among the microstructural factors and their combined effects, which were important references for the design and processing of the superalloy as well as the prediction of mechanical properties. [Display omitted] • Quantifying the weights of multi-modal microstructure morphology parameters. • Quantifying the weights of multi-modal microstructure. • Proposed damage variables coupled with multi-modal microstructure damage evolution. • A fatigue life prediction method coupled with multi-modal microstructure damage was proposed. [ABSTRACT FROM AUTHOR]

The effective characterization of the mechanical property degradation of turbine blades in service for an ultra-long-term had a significant impact on the service safety and maintenance decisions of turbine blades. In this study, the microstructure observation and mechanical property study of the K403 polycrystalline Ni-based superalloy turbine blade under four service times were carried out, using microstructure characterization methods to quantify the microstructure evolution of the superalloy at different parts of the turbine blade with increasing service time. The effects of the microstructure degradation of the superalloy under ultra-long-term service on the mechanical properties of the turbine blade were analyzed. The results show that the microstructural degradation characteristics of the superalloy turbine blades under ultra-long-term service were strongly correlated with the spatial structural characteristics of the turbine blades after service, and it was found that the carbon elements and other elements inside and at the boundary of the carbide showed regular migration behavior with the increase in service time. The regular influence of microstructural degradation of superalloy turbine blades under ultra-long-term service on their mechanical properties was demonstrated. These results can provide empirical support for the study of the predicted residual properties of nickel-based superalloy turbine blades under ultra-long-term service. [Display omitted] • Microstructure evolution of turbine blades under ultra-long-term service was studied. • Mechanical properties of turbine blades under ultra-long-term service were studied. • Influence of microstructure evolution on mechanical properties was studied. • Position-related microstructure evolution and mechanical properties was studied. • Quantitative study of carbide evolution with service time was performed. [ABSTRACT FROM AUTHOR]

The Magnetocaloric Effect (MCE) of directionally solidified Ni 50 Mn 18 Cu 7 Ga 25 alloy was improved based on texturation and introduction of extra phase transition in this paper. Magneto-structural transition is realized in directionally solidified Ni 50 Mn 18 Cu 7 Ga 25 alloy, with a value of Adiabatic Temperature Variation (Δ T ad) of − 1.35 K under magnetic field of 1.5 T. Through simple unidirectional compression, preferred orientation is formed and intermartensitic transformation is introduced in the present alloy. Preferred orientation strengthens the coupling of magnetic and structural transition, intermartensitic transformation makes transformation path more diverse, which both enhance Δ T ad of the directionally solidified alloy. A value of Δ T ad of − 2.34 K is obtained in the deformed alloy under magnetic field of 1.5 T, with a 73.3 % increase compared with the initial state. Moreover, the two incompletely overlapping structural transitions broadens the temperature range of MCE from 4.3 K to 7 K. The present work provides new insight on the MCE optimization of Ni-Mn-Ga alloy by simple and short-term unidirectional compression in view of merging different strengthening mechanisms. [Display omitted] • MCE optimized by different mechanisms: orientation and intermediate transition. • Simple compression to achieve equivalent effect with thermal-stress training. • Incomplete variant selection enriches transition path to increase transition scale. • Partly overlapped CMMT and CMIT improve Δ T ad and widen MCE temperature range. [ABSTRACT FROM AUTHOR]

To improve the electrochemical performance of supercapacitors, pseudocapacitive electrode materials must be synthesized with high surface activity, high electrical conductivity, and ultralong cycle life, which presents a significant challenge. In this study, we reported on the synthesis of sulfur-vacancy-enriched sheet-like Ni 3 S 2 @ZnS composites based on 3D network porous nickel foam (NF) using a two-step electrodeposition protocol. The Ni 3 S 2 @ZnS/NF exhibited a specific capacitance of 1141.9 C g−1 (241.0 mC cm−2) at a current density of 19 A g−1 (5 mA cm−2). The Ni 3 S 2 @ZnS/NF positive electrode was used to fabricate an all-solid asymmetric supercapacitor, which demonstrated an ultrahigh energy density of 12.0 μWh cm−2 at a power density of 7.2 mW cm−2, as well as an ultrahigh capacitance retention rate of 86.7% after 50,000 cycles. Experimental and theoretical results indicated that the introduction of sulfur vacancies could improve the surface activity of the electrode, as well as its hydroxide diffusion and adsorption ability by adjusting the surrounding local electron concentration of cations around them. This accelerated the interfacial redox reaction and resulted in remarkable electrochemical performance for the Ni 3 S 2 @ZnS/NF electrode. This research provides a pathway for the controlled synthesis of 2D nanosheets with vacancy-rich structures and their potential electrochemical applications. • The sulfur-vacancy-enriched sheet-like Ni 3 S 2 @ZnS composite has been conceived. • Abundant sulfur vacancies make the material have high capacitive properties. • The theoretical studies further deepen structure-activity relationship of sulfur vacancies. • An ultrahigh capacitance retention supercapacitor is fabricated. [ABSTRACT FROM AUTHOR]

Hastelloy X is widely used in aerospace because of its excellent high-temperature performance. Laser powder bed fusion (LPBF) can be used to manufacture Hastelloy X and its reinforced materials with more complex structures and better performance. In this study, Hastelloy X reinforced materials added Fe-based metallic glass powder was manufactured using LPBF, and four sequences of 0, 3, 5, and 7 wt%. The introduction of Fe-based metallic glass powder has exhibited notable improvements in the mechanical properties at room and high temperatures. At room temperature (RT), the 5 wt% reinforced material exhibited a larger increase in hardness, with a yield strength and ultimate tensile strength of 856Mpa and 1081 MPa, and the reduction in elongation was only 9.6%. At high temperatures, introducing Fe-based metallic glass enhanced the yield strength and ultimate tensile strength, and the elongation was greatly improved at 800 ℃. The enhancements are mainly due to the grain size refinement caused by the introduction of Fe-based metallic glass powder, which increases dislocation density and grain boundary strengthening. In addition, as the content of Fe-based metallic glass increased, the corrosion resistance of the samples was also improved due to increased Cr and W content and the refinement of grains. This study provides a new research direction for improving the properties of Hastelloy X. • The Hastelloy X and its reinforced materials added Fe-based metallic glass were fabricated via laser powder bed fusion. • The microstructure, corrosion resistance, and mechanical properties of HX, HX3, HX5, and HX7 were investigated. • The addition of Fe-based metallic glass refined the grain size and eliminated microcracks. • HX5 exhibited better comprehensive mechanical properties at both room and high temperatures. • The corrosion resistance improved with the increase in the content of Fe-based metallic glass. [ABSTRACT FROM AUTHOR]

Microstructures and mechanical properties of Ni matrix composites reinforced with amorphous SiO 2 particles by in-situ pyrolysis of polycarbosilane (PCS) coated on Ni powders were studied in this paper. The submicron spherical amorphous SiO 2 particles instead of traditional SiC uniformly distributing in the composites result from the generated silicon source by PCS pyrolysis combined with oxygen impurity in the preparation. The prepared composites achieve high yield strength, 172 MPa, and ultimate tensile strength, 494 MPa, as well as outstanding ductility, total elongation 28.4 %, which is improved 13.9 %, 50.6 % and 160.6 % compared with those for pure Ni samples, respectively. The effects of solid solution strengthening, grain refinement strengthening, reinforcement particle strengthening and dislocations behavior of at amorphous/crystalline interface on the combination of high strength and ductility of the composites were discussed. [Display omitted] • Amorphous SiO 2 reinforced Ni matrix composites were fabricated by in-situ pyrolysis of polycarbosilane coated on Ni powders. • Amorphous SiO 2 instead of crystalline SiC formed by the combination of silicon generated in the pyrolysis with oxygen. • The composites exhibit a combination of excellent tensile strength and ductility. [ABSTRACT FROM AUTHOR]

Exploring newly regulative strategies to design highly efficient electrode materials is of great importance for supercapacitors. Herein, we highlight an interfacial engineering strategy for fabricating NiMn-LDH/V 2 CT x /NF hybrids with heterogeneous structure via a simple hydrothermal reaction. Detailed analysis confirms that the interfacial effect between NiMn-LDH and V 2 CT x enables electron transfer from NiMn-LDH to V 2 CT x in the hybrid material, resulting in improved electrochemical reactivity. As expected, the optimal NiMn-LDH/V 2 CT x /NF-2 demonstrates much better specific capacity than that of its counterparts. Moreover, this strategy can be extended to NiFe-LDH/V 2 CT x /NF hybrids, further proving the coupling effect between MXene and LDH is beneficial for the electrochemical performance. This work presents a new pathway to design advanced materials for supercapacitors. [Display omitted] • Interface engineering of heterogeneous LDH/V 2 CT x MXene hybrids facilitates high reactivity and conductivity. • V 2 CT x nanosheets effectively prevent the agglomeration of LDH nanosheets, which ensure the full exposure of active centers. • LDH/V 2 CT x nanosheet arrays exhibit improved electrochemical performance for supercapacitors. [ABSTRACT FROM AUTHOR]

Pd-based composite electrocatalysts made up of metallic oxide decorated Pd nanoparticles are gaining increasing interest due to their higher catalytic activity and superior stability. In this work, the WO 3 decorated Pd/C nanocomposite (Pd-WO 3 /C) was experimentally prepared using a simple microwave irradiation procedure to probe the electrocatalytic performance toward ethanol oxidation. The electrochemical tests reveal that the Pd-WO 3 /C composite outperforms the commercial Pd/C catalyst in terms of electrocatalytic efficiency. For instance, the mass activity can approach ∼2236 mA·mg−1 Pd , which is roughly twice that of the commercial Pd/C with the same Pd loading (10 wt%). Furthermore, the oxidation-peak current decays slowly over time and cycle, showing the exceptional durability. Based on first-principles calculations, the stronger electronic coupling interplay between Pd and WO 3 based on electron transfer, which provides more active sites by modifying the electron density on the Pd surface, could account for these emphasized advantages. • WO 3 decorated Pd/C composites were synthesized by a microwave irradiation approach. • The mass activity of ethanol oxidation for Pd-WO 3 /C composites is approximately twice that of the commercial Pd/C (10 wt%). • The stronger electronic coupling between Pd and WO 3 is responsible for the improved electrocatalytic activity and stability. [ABSTRACT FROM AUTHOR]

Solid-state electrolytes have become a promising approach for rechargeable lithium batteries with enhanced safety and high energy density. However, the rigid nature of ceramic electrolytes would result in the poor interfacial contact, and polymer electrolytes suffer from inferior electrochemical performance and unsatisfied mechanical strength to suppress Li dendrites. In this work, we report a flexible Li 1.3 Al 0.3 Ti 1.7 (PO 4) 3 (LATP)-reinforced polyvinylidene fluoride (PVDF)-based solid composite electrolyte with superior performances in terms of high ionic conductivity (1.64 × 10−3 S cm−1 at room temperature), high lithium transference number (0.45), wide electrochemical window (0–4.76 V) and enhanced tensile strength (14.2 MPa). The existence of LATP permits the utilization of high Li-salt content which increases the charge carrier concentration. Meanwhile, LATP facilitates the Li+ conduction process and enhances the mechanical strength, leading to a long-term electrochemical stability of symmetric Li cell for 600 h at 0.2 mA cm−2. Assembled with LiFePO 4 cathode, the all-solid-state Li battery delivers a high capacity of 153.7 mA h g−1 at 0.3 C with remarkable cycle stability. This work provides a bright future for composite polymer electrolytes in the application of all-solid-state lithium batteries. • A LATP-reinforced PVDF-based solid-state composite electrolyte was prepared. • The existence of LATP permits the utilization of high Li-salt content. • A long-term electrochemical stability of the Li symmetric cell was achieved. • LiFePO 4 | CPE |Li battery delivers excellent cycle stability at room temperature. [ABSTRACT FROM AUTHOR]

• Pt/g-C 3 N 4 composite photocatalysts synthesized by the low-temperature plasma treatment. • Ultrafine Pt nanoparticles were formed with appropriate ratio of Pt to PtO x and Pt‒N coordination bonds. • Ar plasma can modify the surface structure of g-C 3 N 4 to form oxygen-containing species. • Pt/g-C 3 N 4 -A150 composite exhibited the highest activity with a rate of 1150.8 μmol/h. Advanced photocatalytic systems are actively pursued to address a large number of pressing issues facing chemical engineering in applications. In the photocatalytic process, high-performance catalysts well beyond the current capacity and cost of platinum-carbon composites are required. In this work, Pt/g-C 3 N 4 composite photocatalysts were synthesized using a low-temperature inductively coupled plasma technique to substantially improve the photocatalytic performance for hydrogen production. After the plasma reduction of H 2 PtCl 6 , ultrafine Pt nanoparticles were uniformly deposited on g-C 3 N 4. By changing the plasma discharge power, the size of Pt nanoparticles, the composition and electronic structure of Pt and the interaction between Pt and g-C 3 N 4 can be effectively controlled. Moreover, Ar plasma modified the surface structure of g-C 3 N 4 to form new active oxygen-containing groups. The Ar-plasma-treated Pt/g-C 3 N 4 composites showed excellent activity for hydrogen evolution under visible light. When Pt/g-C 3 N 4 composite was plasma-treated at 150 W for 40 min, the achieved hydrogen production rate was 1150.8 μmol/h, which is about 63.2 and 4.6 times higher compared to the pristine g-C 3 N 4 and Pt/g-C 3 N 4 composite prepared by the photodeposition method, respectively. Our results indicate that the low-temperature inductively coupled plasma treatment is an effective and promising tool to fabricate high-performance catalytic materials. [ABSTRACT FROM AUTHOR]