Inconel 718 is the most popular nickel-based superalloy and is extensively used in aerospace, automotive, and energy industries owing to its extraordinary thermomechanical properties. The effects of different two-step solid solution treatments on microstructure and δ phase precipitation of Inconel 718 alloy were studied, and the transformation mechanism from γ″ metastable phase to δ phase was clarified. The precipitates were statistically analyzed by X-ray diffractometry. The results show that the δ phase content firstly increased, and then decreased with the temperature of the second-step solid solution. The changes in microstructure and δ phase were studied by scanning electron microscopy and transmission electron microscopy. An intragranular δ phase formed in Inconel 718 alloy at the second-step solid solution temperature of 925°C, and its orientation relationship with γ matrix was determined as $[\bar{1}00]_{\delta}//[01\bar{1}]_{\gamma}$ and (010)_δ//(111)_γ. Furthermore, the Vickers hardness of different heat treatment samples was measured, and the sample treated by second-step solid solution at 1010°C reached the maximum hardness of HV 446.84.

The basal texture of traditional magnesium alloy AZ31 is easy to form and exhibits poor plasticity at room temperature. To address these problems, a multi-micro-alloyed high-plasticity Mg–1.8Zn–0.8Gd–0.1Ca–0.2Mn (wt%) alloy was developed using the unique role of rare earth and Ca solute atoms. In addition, the influence of the annealing process on the grain size, second phase, texture, and mechanical properties of the warm-rolled sheet at room temperature was analyzed with the goal of developing high-plasticity magnesium alloy sheets and obtaining optimal thermal-mechanical treatment parameters. The results show that the annealing temperature has a significant effect on the microstructure and properties due to the low alloying content: there are small amounts of larger-sized block and long string phases along the rolling direction (RD), as well as several spherical and rodlike particle phases inside the grains. With increasing annealing temperature, the grain size decreases and then increases, and the morphology, number, and size of the second phase also change correspondingly. The particle phase within the grains vanishes at 450°C, and the grain size increases sharply. In the full recrystallization stage at 300–350°C, the optimum strength-plasticity comprehensive mechanical properties are presented, with yield strengths of 182.1 and 176.9 MPa, tensile strengths of 271.1 and 275.8 MPa in the RD and transverse direction (TD), and elongation values of 27.4% and 32.3%, respectively. Moreover, there are still some larger-sized phases in the alloy that influence its mechanical properties, which offers room for improvement.

A high-zinc composite, 12vol% SiC/Al–13.3 Zn–3.27 Mg–1.07Cu (wt%), with an ultra-high-strength of 781 MPa was successfully fabricated through a powder metallurgy method, followed by an extrusion process. The effects of solid-solution and aging heat treatments on the microstructure and mechanical properties of the composite were extensively investigated. Compared with a single-stage solid-solution treatment, a two-stage solid-solution treatment (470°C/1 h + 480°C/1 h) exhibited a more effective solid-solution strengthening owing to the higher degree of solid-solution and a more uniform microstructure. According to the aging hardness curves of the composite, the optimized aging parameter (100°C/22 h) was determined. Reducing the aging temperature and time resulted in finer and more uniform nanoscale precipitates but only yielded a marginal increase in tensile strength. The fractography analysis revealed that intergranular cracking and interface debonding were the main fracture mechanisms in the ultra-high-strength SiC/Al–Zn–Mg–Cu composites. Weak regions, such as the SiC/Al interface containing numerous compounds and the precipitate-free zones at the high-angle grain boundaries, were identified as significant factors limiting the strength enhancement of the composite. Interfacial compounds, including MgO, MgZn₂, and Cu₅Zn₈, reduced the interfacial bonding strength, leading to interfacial debonding.

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical simulations. Moreover, an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium theory. The results show the following: (1) surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics, and (2) the behavior of the strata as they fail exhibits superimposition characteristics. Generally, failure first occurs in certain superimposed strata slightly far from the goaf. Subsequently, with the constant downward excavation of the orebody, the superimposed strata become damaged both upwards away from and downwards toward the goaf. This process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the goaf. The deep fracture plane generally makes an angle of 12°–20° with the normal to the steeply dipping discontinuities. The effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than expected. The strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling failure. However, the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure, in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever beams. By taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum, the failure scope of the strata (and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving) can be obtained via iterative computations from the key stratum, moving downward toward and upwards away from the goaf.

Magnesium (Mg) alloys are gaining great consideration as body implant materials due to their high biodegradability and biocompatibility. However, they suffer from low corrosion resistance and antibacterial activity. In this research, semi-powder metallurgy followed by hot extrusion was utilized to produce the magnesium oxide@graphene nanosheets/magnesium (MgO@GNS/Mg) composite to improve mechanical, corrosion and cytocompatibility characteristics. Investigations have revealed that the incorporation of MgO@GNS nanohybrids into Mg-based composite enhanced microhardness and compressive strength. In vitro, osteoblast cell culture tests show that using MgO@GNS nanohybrid fillers enhances osteoblast adhesion and apatite mineralization. The presence of MgO@GNS nanoparticles in the composites decreased the opening defects, micro-cracks and micro-pores of the composites thus preventing the penetration of the corrosive solution into the matrix. Studies demonstrated that the MgO@GNS/Mg composite possesses excellent antibacterial properties because of the combination of the release of MgO and physical damage to bacterium membranes caused by the sharp edges of graphene nanosheets that can effectively damage the cell wall thereby facilitating penetration into the bacterial lipid bilayer. Therefore, the MgO@GNS/Mg composite with high mechanical strength, antibacterial activity and corrosion resistance is considered to be a promising material for load-bearing implant applications.

Vanadium and its derivatives are used in various industries, including steel, metallurgy, pharmaceuticals, and aerospace engineering. Although China has massive reserves of stone coal resources, these resources have low grades. Therefore, the effective extraction and recovery of metallic vanadium from stone coal is an important way to realize the efficient resource utilization of stone coal vanadium ore. Herein, Bacillus mucilaginosus was selected as the leaching strain. The vanadium leaching rate reached 35.5% after 20 d of bioleaching under optimal operating conditions. The cumulative vanadium leaching rate in the contact group reached 35.5%, which was higher than that in the noncontact group (9.3%). The metabolites of B. mucilaginosus, such as oxalic, tartaric, citric, and malic acids, dominated in bioleaching, accounting for 73.8% of the vanadium leaching rate. Interestingly, during leaching, the presence of stone coal stimulated the expression of carbonic anhydrase in bacterial cells, and enzyme activity increased by 1.335–1.905 U. Enzyme activity positively promoted the production of metabolite organic acids, and total organic acid content increased by 39.31 mg·L⁻¹, resulting in a reduction of 2.51 in the pH of the leaching system with stone coal. This effect favored the leaching of vanadium from stone coal. Atomic force microscopy illustrated that bacterial leaching exacerbated corrosion on the surface of stone coal beyond 10 nm. Our study provides a clear and promising strategy for exploring the bioleaching mechanism from the perspective of microbial enzyme activity and metabolites.

This study focused on the investigation of the edge effect of diamond films deposited by microwave plasma chemical vapor deposition. Substrate bulge height is a factor that affects the edge effect, and it was used to simulate plasma and guide the diamond-film deposition experiments. Finite-element software COMSOL Multiphysics was used to construct a multiphysics (electromagnetic, plasma, and fluid heat transfer fields) coupling model based on electron collision reaction. Raman spectroscopy and scanning electron microscopy were performed to characterize the experimental growth and validate the model. The simulation results reflected the experimental trends observed. Plasma discharge at the edge of the substrate accelerated due to the increase in Δh (Δh = 0–3 mm), and the values of electron density (n _e), molar concentration of H (C _H), and molar concentration of $\text{CH}_{3} \ (C_{\text{CH}_{3}})$ doubled at the edge (for the special concave sample with Δh = −1 mm, the active chemical groups exhibited a decreased molar concentration at the edge of the substrate). At Δh = 0–3 mm, a high diamond growth rate and a large diamond grain size were observed at the edge of the substrate, and their values increased with Δh. The uniformity of film thickness decreased with Δh. The Raman spectra of all samples revealed the first-order characteristic peak of diamond near 1332 cm⁻¹. When Δh = −1 mm, tensile stress occurred in all regions of the film. When Δh = 1–3 mm, all areas in the film exhibited compressive stress.

The effects of deformation temperature on the transformation-induced plasticity (TRIP)-aided 304L, twinning-induced plasticity (TWIP)-assisted 316L, and highly alloyed stable 904L austenitic stainless steels were compared for the first time to tune the mechanical properties, strengthening mechanisms, and strength–ductility synergy. For this purpose, the scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), X-ray diffraction (XRD), tensile testing, work-hardening analysis, and thermodynamics calculations were used. The induced plasticity effects led to a high temperature-dependency of work-hardening behavior in the 304L and 316L stainless steels. As the deformation temperature increased, the metastable 304L stainless steel showed the sequence of TRIP, TWIP, and weakening of the induced plasticity mechanism; while the disappearance of the TWIP effect in the 316L stainless steel was also observed. However, the solid-solution strengthening in the 904L superaustenitic stainless steel maintained the tensile properties over a wide temperature range, surpassing the performance of 304L and 316L stainless steels. In this regard, the dependency of the total elongation on the deformation temperature was less pronounced for the 904L alloy due to the absence of additional plasticity mechanisms. These results revealed the importance of solid–solution strengthening and the associated high friction stress for superior mechanical behavior over a wide temperature range.

In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction of the explosion stress wave and blasting effect. Herein, we examine the explosion wave field and rock breaking effect in terms of shock wave collision, stress change of the blast hole wall in the collision zone, and crack propagation in the collision zone. The produced shock wave on the collision surface has an intensity surpassing the sum of the intensities of the two colliding explosion shock waves. At the collision location, the kinetic energy is transformed into potential energy with a reduction in particle velocity at the wave front and the wave front pressure increases. The expansion form of the superposed shock wave is dumbbell-shaped, the shock wave velocity in the collision area is greater than the radial shock wave velocity, and the average propagation angle of the explosion shock waves is approximately 60°. Accordingly, a fitted relationship between blast hole wall stress and explosion wave propagation angle in the superposition area is plotted. Under the experimental conditions, the superimposed explosion wave stress of the blast hole wall is approximately 1.73 times the singleexplosion wave incident stress. The results of the model test and numerical simulations reveal that large-scale radial fracture cracks were generated on the blast hole wall in the superimposed area, and the width of the crack increased. The width of the large-scale radial fracture cracks formed by a strong impact is approximately 5% of the blast hole length. According to the characteristics of blast hole wall compression, the mean peak pressures of the strongly superimposed area are approximately 1.48 and 1.84 times those of the weakly superimposed and nonsuperimposed areas, respectively.

In low-density steel, κ-carbides primarily precipitate in the form of nanoscale particles within austenite grains. However, their precipitation within ferrite matrix grains has not been comprehensively explored, and the second-phase evolution mechanism during aging remains unclear. In this study, the crystallographic characteristics and morphological evolution of κ-carbides in Fe–28Mn–10Al–0.8C (wt%) low-density steel at different aging temperatures and times and the impacts of these changes on the steels’ microhardness and properties were comprehensively analyzed. Under different heat treatment conditions, intragranular κ-carbides exhibited various morphological and crystallographic characteristics, such as acicular, spherical, and short rod-like shapes. At the initial stage of aging, acicular κ-carbides primarily precipitated, accompanied by a few spherical carbides. κ-Carbides grew and coarsened with aging time, the spherical carbides were considerably reduced, and rod-like carbides coarsened. Vickers hardness testing demonstrated that the material’s hardness was affected by the volume fraction, morphology, and size of κ-carbides. Extended aging at higher temperatures led to an increase in carbide size and volume fraction, resulting in a gradual rise in hardness. During deformation, the primary mechanisms for strengthening were dislocation strengthening and second-phase strengthening. Based on these findings, potential strategies for improving material strength are proposed.

NiMZn/C@melamine sponge-derived carbon (MSDC) composites (M = Co, Fe, and Mn) were prepared by a vacuum pumping solution method followed by carbonization. A large number of carbon nanotubes (CNTs) homogeneously attached to the surfaces of the three-dimensional cross-linked of the sponge-derived carbon in the NiCoZn/C@MSDC composite, and CNTs were detected in the NiFeZn/C@MSDC and NiMnZn/C@MSDC composites. Ni₃ZnC_0.7, Ni₃Fe, and MnO in-situ formed in the NiFeZn/C@MSDC and NiMnZn/C@MSDC composites. The CNTs in the NiCoZn/C@MSDC composite efficiently modulated its complex permittivity. Thus, the composite exhibited the best performance among the composites, with the minimum reflection loss (RL_min) of −33.1 dB at 18 GHz and thickness of 1.4 mm. The bandwidth for RL of ≤−10 dB was up to 5.04 GHz at the thickness of 1.7 mm and loading of 25wt%. The optimized impedance matching, enhanced interfacial and dipole polarization, remarkable conduction loss, and multiple reflections and scattering of the incident microwaves improved the microwave absorption performance. The effects of Co, Ni, and Fe on the phase and morphology provided an alternative way for developing highly efficient and broadband microwave absorbers.

The precipitation of Fe₃O₄ particles and the accompanied formation of Fe₃O₄-wrapped copper structure are the main obstacles to copper recovery from the molten slag during the pyrometallurgical smelting of copper concentrates. Herein, the commercial powdery pyrite or anthracite is replaced with pyrite–anthracite pellets as the reductants to remove a large amount of Fe₃O₄ particles in the molten slag, resulting in a deep fracture in the Fe₃O₄-wrapped copper microstructure and the full exposure of the copper matte cores. When 1wt% composite pellet is used as the reductant, the copper matte droplets are enlarged greatly from 25 µm to a size observable by the naked eye, with the copper content being enriched remarkably from 1.2wt% to 4.5wt%. Density functional theory calculation results imply that the formation of the Fe₃O₄-wrapped copper structure is due to the preferential adhesion of Cu₂S on the Fe₃O₄ particles. X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy results all reveal that the high-efficiency conversion of Fe₃O₄ to FeO can decrease the volume fraction of the solid phase and promote the depolymerization of silicate network structure. As a consequence, the settling of copper matte droplets is enhanced due to the lowered slag viscosity, contributing to the high efficiency of copper–slag separation for copper recovery. The results provide new insights into the enhanced in-situ enrichment of copper from molten slag.

In the present work, plastic deformation mechanisms were initially tailored by adjusting the deformation temperature in the range of 0 to 200°C in AISI 304L austenitic stainless steel, aiming to optimize the strength-ductility synergy. It was shown that the combined twinning-induced plasticity (TWIP)/transformation-induced plasticity (TRIP) effects and a wider strain range for the TRIP effect up to higher strains by adjusting the deformation temperature are good strategies to improve the strength-ductility synergy of this metastable stainless steel. In this regard, by consideration of the observed temperature-dependency of plastic deformation, the controlled sequence of TWIP and TRIP effects for archiving superior strength-ductility trade-off was intended by the pre-designed temperature jump tensile tests. Accordingly, the optimum tensile toughness of 846 MJ/m³ and total elongation to 133% were obtained by this strategy via exploiting the advantages of the TWIP effect at 100°C and the TRIP effect at 25°C at the later stages of the straining. Consequently, a deformation-temperature-transformation (DTT) diagram was developed for this metastable alloy. Moreover, based on work-hardening analysis, it was found that the main phenomenon constraining further improvement in the ductility and strengthening was the yielding of the deformation-induced α′-martensite.

With the continuous development of mineral resources to high altitude areas, the study of sulfide ore flotation in unconventional systems has been emphasized. There is a consensus that moderate oxidation of sulfide ore is beneficial to flotation, but the specific suitable dissolved oxygen value is inconclusive, and there are few studies on sulfide ore flotation under low dissolved oxygen environment at high altitude. In this paper, we designed and assembled an atmosphere simulation flotation equipment to simulate the flotation of pyrite at high altitude by controlling the partial pressure of N₂/O₂ and dissolved oxygen under atmospheric conditions. X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), Fourier transform infrared spectrometer (FT-IR), UV-vis spectrophotometer, zeta potential, and contact angle measurements were used to reveal the effects of surface oxidation and agent adsorption on pyrite at high altitude (4600 m dissolved oxygen (DO) = 4.0 mg/L). The results of pure mineral flotation indicated that the high altitude and low dissolved oxygen environment is favorable for pyrite flotation. Contact angle measurements and XPS analysis showed that the high altitude atmosphere slows down the oxidation of pyrite surface, facilitates S _n ²⁻/S⁰ production and enhances surface hydrophobicity. Electrochemical calculations and zeta potential analysis showed that the influence of atmosphere on the form of pyrite adsorption is small, and the different atmospheric conditions are consistent with dixanthogen electrochemical adsorption, with lower Zeta potential under high altitude atmosphere and significant potential shift after sodium isobutyl xanthate (SIBX) adsorption. The results of FT-IR, UV-vis, and AFM analysis showed that SIBX adsorbed more on the surface of pyrite under high altitude atmosphere and adsorbed on the surface in a mesh structure composed of column/block. The results of the experimental study revealed the reasons for the easy flotation of sulfide ores at high altitude with less collector dosage, and confirmed that the combined DO–pH regulation is beneficial to achieve more efficient flotation of pyrite.

We discussed the decrease in residual stress, precipitation evolution, and mechanical properties of GH4151 alloy in different annealing temperatures, which were studied by the scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), and electron backscatter diffraction (EBSD). The findings reveal that annealing processing has a significant impact on diminishing residual stresses. As the annealing temperature rose from 950 to 1150°C, the majority of the residual stresses were relieved from 60.1 MPa down to 10.9 MPa. Moreover, the stress relaxation mechanism transitioned from being mainly controlled by dislocation slip to a combination of dislocation slip and grain boundary migration. Meanwhile, the annealing treatment promotes the decomposition of the Laves, accompanied by the precipitation of μ-(Mo₆Co₇) starting at 950°C and reaching a maximum value at 1050°C. The tensile strength and plasticity of the annealing alloy at 1150°C reached the maximum (1394 MPa, 56.1%) which was 131%, 200% fold than those of the as-cast alloy (1060 MPa, 26.6%), but the oxidation process in the alloy was accelerated at 1150°C. The enhancement in durability and flexibility is primarily due to the dissolution of the brittle phase, along with the shape and dispersal of the γ′ phase.

BiFeO₃ (BFO) has received considerable attention as a lead-free ferroelectric film due to its large theoretical remnant polarization. However, BFO suffers from a large leakage current, resulting in poor ferroelectric properties. Herein, the sol–gel method was used to deposit a series of BFO-based thin films on fluorine-doped tin oxide substrates, and the effects of the substitution of the elements Co, Cu, Mn (B-site) and Sm, Eu, La (A-site) on the crystal structure, ferroelectricity, and leakage current of the BFO-based thin films were investigated. Results confirmed that lattice distortion by X-ray diffraction can be attributed to the substitution of individual elements in the BFO-based films. Sm and Eu substitutions contribute to the lattice distortion in a pseudo-cubic structure, while La is biased toward pseudo-tetragonal. Piezoelectric force microscopy confirmed that reversible switching of ferroelectric domains by nearly 180° can be realized through the prepared films. The ferroelectric hysteresis loops showed that the order for the polarization contribution is as follows: Cu > Co > Mn (B-site), Sm > La > Eu (A-site). The current density voltage curves indicated that the order for leakage contribution is as follows: Mn < Cu < Co (B-site), La < Eu < Sm (A-site). Scanning electron microscopy showed that the introduction of Cu elements facilitates the formation of dense grains, and the grain size distribution statistics proved that La element promotes the reduction of grain size, leading to the increase of grain boundaries and the reduction of leakage. Finally, a Bi_0.985Sm_0.045La_0.03Fe_0.96Co_0.02Cu_0.02O₃ (SmLa-CoCu) thin film with a qualitative leap in the remnant polarization from 25.5 (Bi_0.985Sm_0.075FeO₃) to 98.8 µC/cm² (SmLa-CoCu) was prepared through the synergistic action of Sm, La, Co, and Cu elements. The leakage current is also drastically reduced from 160 to 8.4 mA/cm² at a field strength of 150 kV/cm. Thus, based on the increasing entropy strategy of chemical engineering, this study focuses on enhancing ferroelectricity and decreasing leakage current, providing a promising path for the advancement of ferroelectric devices.

To increase the processability and plasticity of the selective laser melting (SLM) fabricated Al–Mn–Mg–Er–Zr alloys, a novel TiB₂-modified Al–Mn–Mg–Er–Zr alloy with a mixture of Al–Mn–Mg–Er–Zr and nano-TiB₂ powders was fabricated by SLM. The processability, microstructure, and mechanical properties of the alloy were systematically investigated by density measurement, microstructure characterization, and mechanical properties testing. The alloys fabricated at 250 W displayed higher relative densities due to a uniformly smooth top surface and appropriate laser energy input. The maximum relative density value of the alloy reached (99.7 ± 0.1)%, demonstrating good processability. The alloy exhibited a duplex grain microstructure consisting of columnar regions primarily and equiaxed regions with TiB₂, Al₆Mn, and Al₃Er phases distributed along the grain boundaries. After directly aging treatment at a high temperature of 400°C, the strength of the SLM-fabricated TiB₂/Al–Mn–Mg–Er–Zr alloy increased due to the precipitation of the secondary Al₆Mn phases. The maximum yield strength and ultimate tensile strength of the aging alloy were measured to be (374 ± 1) and (512 ± 13) MPa, respectively. The SLM-fabricated TiB₂/Al–Mn–Mg–Er–Zr alloy demonstrates exceptional strength and thermal stability due to the synergistic effects of the inhibition of grain growth, the incorporation of TiB₂ nanoparticles, and the precipitation of secondary Al₆Mn nanoparticles.

The substantial arsenic (As) content present in arsenic-containing bio-leaching residue (ABR) presents noteworthy environmental challenges attributable to its inherent instability and susceptibility to leaching. Given its elevated calcium sulfate content, ABR exhibits considerable promise for industrial applications. This study delved into the feasibility of utilizing ABR as a source of sulfates for producing super sulfated cement (SSC), offering an innovative binder for cemented paste backfill (CPB). Thermal treatment at varying temperatures of 150, 350, 600, and 800°C was employed to modify ABR’s performance. The investigation encompassed the examination of phase transformations and alterations in the chemical composition of As within ABR. Subsequently, the hydration characteristics of SSC utilizing ABR, with or without thermal treatment, were studied, encompassing reaction kinetics, setting time, strength development, and microstructure. The findings revealed that thermal treatment changed the calcium sulfate structure in ABR, consequently impacting the resultant sample performance. Notably, calcination at 600°C demonstrated optimal modification effects on both early and long-term strength attributes. This enhanced performance can be attributed to the augmented formation of reaction products and a densified microstructure. Furthermore, the thermal treatment elicited modifications in the chemical As fractions within ABR, with limited impact on the As immobilization capacity of the prepared binders.

Electronic devices have become ubiquitous in our daily lives, leading to a surge in the use of microwave absorbers and wearable sensor devices across various sectors. A prime example of this trend is the aramid nanofibers/polypyrrole/nickel (APN) aerogels, which serve dual roles as both microwave absorbers and pressure sensors. In this work, we focused on the preparation of aramid nanofibers/polypyrrole (AP15) aerogels, where the mass ratio of aramid nanofibers to pyrrole was 1:5. We employed the oxidative polymerization method for the preparation process. Following this, nickel was thermally evaporated onto the surface of the AP15 aerogels, resulting in the creation of an ultralight (9.35 mg·cm⁻³). This aerogel exhibited a porous structure. The introduction of nickel into the aerogel aimed to enhance magnetic loss and adjust impedance matching, thereby improving electromagnetic wave absorption performance. The minimum reflection loss value achieved was −48.7 dB, and the maximum effective absorption bandwidth spanned 8.42 GHz with a thickness of 2.9 mm. These impressive metrics can be attributed to the three-dimensional network porous structure of the aerogel and perfect impedance matching. Moreover, the use of aramid nanofibers and a three-dimensional hole structure endowed the APN aerogels with good insulation, flame-retardant properties, and compression resilience. Even under a compression strain of 50%, the aerogel maintained its resilience over 500 cycles. The incorporation of polypyrrole and nickel particles further enhanced the conductivity of the aerogel. Consequently, the final APN aerogel sensor demonstrated high sensitivity (10.78 kPa⁻¹) and thermal stability. In conclusion, the APN aerogels hold significant promise as ultra-broadband microwave absorbers and pressure sensors.

The synthesis of carbide coatings on graphite substrates using molten salt synthesis (MSS), has garnered significant interest due to its cost-effective nature. This study investigates the reaction process and growth kinetics involved in MSS, shedding light on key aspects of the process. The involvement of Ti powder through liquid-phase mass transfer is revealed, where the diffusion distance and quantity of Ti powder play a crucial role in determining the reaction rate by influencing the C content gradient on both sides of the carbide. Furthermore, the growth kinetics of the carbide coating are predominantly governed by the diffusion behavior of C within the carbide layer, rather than the chemical reaction rate. To analyze the kinetics, the thickness of the carbide layer is measured with respect to heat treatment time and temperature, unveiling a parabolic relationship within the temperature range of 700–1300°C. The estimated activation energy for the reaction is determined to be 179283 J·mol⁻¹. These findings offer valuable insights into the synthesis of carbide coatings via MSS, facilitating their optimization and enhancing our understanding of their growth mechanisms and properties for various applications.

The safety and longevity of key blast furnace (BF) equipment determine the stable and low-carbon production of iron. This paper presents an analysis of the heat transfer characteristics of these components and the uneven distribution of cooling water in parallel pipes based on hydrodynamic principles, discusses the feasible methods for the improvement of BF cooling intensity, and reviews the preparation process, performance, and damage characteristics of three key equipment pieces: coolers, tuyeres, and hearth refractories. Furthermoere, to attain better control of these critical components under high-temperature working conditions, we propose the application of optimized technologies, such as BF operation and maintenance technology, self-repair technology, and full-lifecycle management technology. Finally, we propose further researches on safety assessments and predictions for key BF equipment under new operating conditions.

This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel. Results indicated that the microstructure of the Cr–Si micro-alloyed press hardened steel consisted of lath martensite, M₂₃C₆ carbides, and retained austenite. The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel. In addition, after oxidation at 930°C for 5 min, the thickness of the oxide scales on the Cr–Si micro-alloyed press hardened steel is less than 5 µm, much thinner than 45.50 µm-thick oxide scales on 22MnB5. The oxide scales of the Cr–Si micro-alloyed steel are composed of Fe₂O₃, Fe₃O₄, mixed spinel oxide (FeCr₂O₄ and Fe₂SiO₄), and amorphous SiO₂. Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase. Due to the increase of spinel FeCr₂O₄ and Fe₂SiO₄ phase in the inner oxide scale and the amorphous SiO₂ close to the substrate, the oxidation resistance of the Cr–Si micro-alloyed press hardened steel is improved.

This work aims to investigate the mechanical properties and interfacial characteristics of 6061 Al alloy plates fabricated by hot-roll bonding (HRB) based on friction stir welding. The results showed that ultimate tensile strength and total elongation of the hot-rolled and aged joints increased with the packaging vacuum, and the tensile specimens fractured at the matrix after exceeding 1 Pa. Non-equilibrium grain boundaries were formed at the hot-rolled interface, and a large amount of Mg₂Si particles were linearly precipitated along the interfacial grain boundaries (IGBs). During subsequent heat treatment, Mg₂Si particles dissolved back into the matrix, and Al₂O₃ film remaining at the interface eventually evolved into MgO. In addition, the local IGBs underwent staged elimination during HRB, which facilitated the interface healing due to the fusion of grains at the interface. This process was achieved by the dissociation, emission, and annihilation of dislocations on the IGBs.

Inhibitors are important for flotation separation of quartz and feldspar. In this study, a novel combined inhibitor was used to separate quartz and feldspar in near-neutral pulp. Selective inhibition of the combined inhibitor was assessed by micro-flotation experiments. And a series of detection methods were used to detect differences in the surface properties of feldspars and quartz after flotation reagents and put forward the synergistic strengthening mechanism. The outcomes were pointed out that pre-mixing combined inhibitors were more effective than the addition of Ca²⁺ and SS in sequence under the optimal proportion of 1:5. A concentrate from artificial mixed minerals that was characterized by a high quartz grade and a high recovery was acquired, and was found to be 90.70wt% and 83.70%, respectively. It was demonstrated that the combined inhibitor selectively prevented the action of the collector and feldspar from Fourier-transform infrared (FT-IR) and adsorption capacity tests. The results of X-ray photoelectron spectroscopy (XPS) indicated that Ca²⁺ directly interacts with the surface of quartz to increase the adsorption of collectors. In contrast, the chemistry property of Al on the feldspar surface was altered by combined inhibitor due to Na⁺ and Ca²⁺ taking the place of K⁺, resulting in the composite inhibitor forms a hydrophilic structure, which prevents the adsorption of the collector on the surface of feldspar by interacting with the Al active site. The combination of Ca²⁺ and SS synergically strengthens the difference of collecting property between quartz and feldspar by collector, thus achieving the effect of efficient separation. A new strategy for flotation to separate quartz from feldspar in near-neutral pulp was provided.

To enhance the Young’s modulus (E) and strength of titanium alloys, we designed titanium matrix composites with interconnected microstructure based on the Hashin-Shtrikman theory. According to the results, the in-situ reaction yielded an interconnected microstructure composed of Ti₂C particles when the Ti₂C content reached 50vol%. With widths of 10 and 230 nm, the intraparticle Ti lamellae in the prepared composite exhibited a bimodal size distribution due to precipitation and the unreacted Ti phase within the grown Ti₂C particles. The composites with interconnected microstructure attained superior properties, including E of 174.3 GPa and ultimate flexural strength of 1014 GPa. Compared with that of pure Ti, the E of the composite was increased by 55% due to the high Ti₂C content and interconnected microstructure. The outstanding strength resulted from the strong interfacial bonding, load-bearing capacity of interconnected Ti₂C particles, and bimodal intraparticle Ti lamellae, which minimized the average crack driving force. Interrupted flexural tests revealed preferential crack initiation along the {001} cleavage plane and grain boundary of Ti₂C in the region with the highest tensile stress. In addition, the propagation can be efficiently inhibited by interparticle Ti grains, which prevented the brittle fracture of the composites.

To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs), 10mol% Ta⁵⁺ doped in the B site of strontium ferrite perovskite oxide (SrTa_0.1Fe_0.9O_3−δ, STF) is investigated and optimized. The effects of Ta⁵⁺ doping on structure, transition metal reduction, oxygen nonstoichiometry, thermal expansion, and electrical performance are evaluated systematically. Via 10mol% Ta⁵⁺ doping, the thermal expansion coefficient (TEC) decreased from 34.1 × 10⁻⁶ (SrFeO_3−δ) to 14.6 × 10⁻⁶ K⁻¹ (STF), which is near the TEC of electrolyte (13.3 × 10⁻⁶ K⁻¹ for Sm_0.2Ce_0.8O_1.9, SDC), indicates excellent thermomechanical compatibility. At 550–750°C, STF shows superior oxygen vacancy concentrations (0.262 to 0.331), which is critical in the oxygen-reduction reaction (ORR). Oxygen temperature-programmed desorption (O₂-TPD) indicated the thermal reduction onset temperature of iron ion is around 420°C, which matched well with the inflection points on the thermos-gravimetric analysis and electrical conductivity curves. At 600°C, the STF electrode shows area-specific resistance (ASR) of 0.152 Ω·cm² and peak power density (PPD) of 749 mW·cm⁻². ORR activity of STF was further improved by introducing 30wt% Sm_0.2Ce_0.8O_1.9 (SDC) powder, STF + SDC composite cathode achieving outstanding ASR value of 0.115 Ω·cm² at 600°C, even comparable with benchmark cobalt-containing cathode, Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCF). Distribution of relaxation time (DRT) analysis revealed that the oxygen surface exchange and bulk diffusion were improved by forming a composite cathode. At 650°C, STF + SDC composite cathode achieving an outstanding PPD of 1117 mW·cm⁻². The excellent results suggest that STF and STF + SDC are promising air electrodes for IT-SOFCs.

A novel method was developed to enhance the utilization rate of steel slag (SS). Through treatment of SS with phosphoric acid and aminopropyl triethoxysilane (KH550), we obtained modified SS (MSS), which was used to prepare MSS/wood-plastic composites (MSS/WPCs) by replacing talcum powder (TP). The composites were fabricated through melting blending and hot pressing. Their mechanical and combustion properties, which comprise heat release, smoke release, and thermal stability, were systematically investigated. MSS can improve the mechanical strength of the composites through grafting reactions between wood powder and thermoplastics. Notably, MSS/WPC#50 (16wt% MSS) with an MSS-to-TP mass ratio of 1:1 exhibited optimal comprehensive performance. Compared with those of WPC#0 without MSS, the tensile, flexural, and impact strengths of MSS/WPC#50 were increased by 18.5%, 12.8%, and 18.0%, respectively. Moreover, the MSS/WPC#50 sample achieved the highest limited oxygen index of 22.5%, the highest vertical burning rating at the V-1 level, and the lowest horizontal burning rate at 44.2 mm/min. The formation of a dense and stable char layer led to improved thermal stability and a considerable reduction in heat and smoke releases of MSS/WPC#50. However, the partial replacement of TP with MSS slightly compromised the mechanical and flame-retardant properties, possibly due to the weak grafting caused by SS powder agglomeration. These findings suggest the suitability of MSS/WPCs for high-value-added applications as decorative panels indoors or outdoors.

The structure of the oxide film on FGH96 alloy powders significantly influences the mechanical properties of superalloys. In this study, FGH96 alloy powders with various oxygen contents were investigated using high-resolution transmission electron microscopy and atomic probe technology to elucidate the structure evolution of the oxide film. Energy dispersive spectrometer analysis revealed the presence of two distinct components in the oxide film of the alloy powders: amorphous oxide layer covering the γ matrix and amorphous oxide particles above the carbide. The alloying elements within the oxide layer showed a laminated distribution, with Ni, Co, Cr, and Al/Ti, which was attributed to the decreasing oxygen equilibrium pressure as oxygen diffused from the surface into the γ matrix. On the other hand, Ti enrichment was observed in the oxide particles caused by the oxidation and decomposition of the carbide phase. Comparative analysis of the oxide film with oxygen contents of 140, 280, and 340 ppm showed similar element distributions, while the thickness of the oxide film varies approximately at 9, 14, and 30 nm, respectively. These findings provide valuable insights into the structural analysis of the oxide film on FGH96 alloy powders.

To enhance the long-term corrosion resistance of the plasma electrolytic oxidation (PEO) coating on the magnesium (Mg) alloy, an inorganic salt combined with corrosion inhibitors was used for posttreatment of the coating. In this study, the corrosion performance of PEO-coated AM50 Mg was significantly improved by loading sodium lauryl sulfonate (SDS) and sodium dodecyl benzene sulfonate into Ba(NO₃)₂ post-sealing solutions. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectrometer, and ultraviolet–visible analyses showed that the inhibitors enhanced the incorporation of BaO₂ into PEO coatings. Electrochemical impedance showed that post-sealing in Ba(NO₃)₂/SDS treatment enhanced corrosion resistance by three orders of magnitude. The total impedance value remained at 926 Ω·cm² after immersing in a 0.5wt% NaCl solution for 768 h. A salt spray test for 40 days did not show any obvious region of corrosion, proving excellent post-sealing by Ba(NO₃)₂/SDS treatment. The corrosion resistance of the coating was enhanced through the synergistic effect of BaO₂ pore sealing and SDS adsorption.

Hot torsion tests were performed on the Al-7Mg alloy at the temperature ranging from 300 to 500°C and strain rates between 0.05 and 5 s⁻¹ to explore the progressive dynamic recrystallization (DRX) and texture behaviors. The DRX behavior of the alloy manifested two distinct stages: Stage 1 at strain of ≤2 and Stage 2 at strains of ≥2. In Stage 1, there was a slight increase in the DRXed grain fraction (X _DRX) with predominance of discontinuous DRX (DDRX), followed by a modest change in X _DRX until the transition to Stage 2. Stage 2 was marked by an accelerated rate of DRX, culminating in a substantial final X _DRX of ∼0.9. Electron backscattered diffraction (EBSD) analysis on a sample in Stage 2 revealed that continuous DRX (CDRX) predominantly occurred within the ($(1\bar{2}1)$) [001] grains, whereas the (111) [110] grains underwent a geometric DRX (GDRX) evolution without a noticeable sub-grain structure. Furthermore, a modified Avrami’s DRX kinetics model was utilized to predict the microstructural refinement in the Al-7Mg alloy during the DRX evolution. Although this kinetics model did not accurately capture the DDRX behavior in Stage 1, it effectively simulated the DRX rate in Stage 2. The texture index was employed to assess the evolution of the texture isotropy during hot-torsion test, demonstrating significant improvement (>75%) in texture randomness before the commencement of Stage 2. This initial texture evolution is attributed to the rotation of parent grains and the substructure evolution, rather than to an increase in X _DRX.