Cu-diamond composites (CDCS) possess great potential in thermal management materials. However, they face critical scientific challenges, including weak interfacial bonding and poor high-temperature performance of the Cu matrix. To improve the bonding at the Cu-diamond interface and to construct a structure of ceramic-reinforced matrix, this study employed Cr2AlC and Cu-coated diamond powders as the raw materials to prepare the composites sintered at 970 °C via vacuum hot-press sintering. Cu(Al)-diamond composites co-reinforced with Cr3C2 and Al2O3 (CDCSCA) were successfully fabricated. Microstructure results obtained by XRD, SEM, and EDS indicate that Cr2AlC decomposes within the composites during sintering to form Cr3C2 and promotes the formation of Al2O3, which together act as ceramic phases embedded in the Cu(Al) matrix to improve its high-temperature performance. In addition, Cr2AlC promotes the formation of a Cr3C2 interfacial layer at the Cu(Al) matrix-diamond interface, thereby improving the interfacial bonding.
The transition toward sustainable materials has generated growing interest in biocomposites that combine bio-based polymers with natural fillers. In this study, polylactic acid (PLA) was reinforced with two biomass fillers, specifically Ailanthus altissima (AIL) and Chamaerops humilis (CH), incorporated at 10 and 20 wt%, and processed via melt extrusion followed by Fused Deposition Modeling (FDM) to obtain printable filaments. A comprehensive characterization of mechanical, morphological, thermal, and environmental properties was carried out. Although all biocomposites showed moderate reductions in flexural and impact strength compared with neat PLA, their tensile strength and elongation at break improved significantly, particularly in AIL-based composites. SEM analysis revealed superior filler dispersion and matrix-filler adhesion in AIL systems, correlating with enhanced ductility and reduced void content. The introduction of the ''intraphase'' parameter (i.e., polymeric phase filling the pores) quantified by pycnometry and supported by FTIR-ATR analysis allowed the description of the degree of matrix penetration into filler lumens and its effect on mechanical performance. AIL-based composites exhibited higher intraphase values and retained more polymer within filler voids, resulting in better stress transfer and reduced brittleness. Additionally, a preliminary assessment of sustainability benefit highlighted significant environmental advances, with CO2 savings up to 5.4 kg per 100 kg of product for AIL20 due to both the renewable origin of PLA and the valorization of invasive or waste biomasses. These findings suggest that AIL and CH fillers represented viable and sustainable alternatives to conventional reinforcements in FDM-printed PLA composites.
Giga-strength Al/SiC composites with exceptional strength (>1 GPa) and stiffness (>200 GPa), yet low density (<3.0 g/cm3), are produced through a simple yet transformative process that utilizes nitrogen's critical influence on the matrix-reinforcement interface, known as Nitrogen-Induced Self-Forming Aluminum Composites (NISFAC). The Al matrix, reinforced with 20–50 vol% microsized SiC particles, exhibited significant enhancements of mechanical properties, with a 471.93 % increase in compressive strength and a 189.33 % improvement in Young's modulus compared to monolithic aluminum. These improvements are attributed to the formation of aluminum nitride (AlN) and aluminum oxynitride (Al(O)N), which originate on the Al powder surface and integrate into the matrix and Al–SiC interface during the nitrogen-induced self-sintering process. Detailed microstructural analysis revealed the critical role of these phases in load transfer from the matrix to the reinforcement. Mechanistic insights and novel predictive models further validated the contributions of reinforcements to the yield strength and Young's modulus. The Al/50 %SiC composite achieved compressive strength over 1 GPa and Young's modulus over 200 GPa, highlighting its potential for advanced structural applications.
Mg batteries have high energy density, economic safety, and environmental friendliness. They show great potential as an ideal energy storage technology. This review summarizes the limitations of Mg batteries and explores the complex reactions at the Mg anode/electrolyte interface. It focuses on critical issues such as the dissolution of Mg anodes, the evolution of hydrogen gas, the formation of a passivation layer that hinders Mg²⁺ migration, and dendrite growth. To address these interface problems, the review discusses strategies to improve interface reactions. These include the structural design of Mg anodes, suitable substitute materials for the anode, and artificial solid electrolyte interphase films. Finally, it outlines the future research directions for the ideal Mg anode interfaces. The goal is to develop more efficient interface design schemes and optimization strategies to advance Mg battery technology further.
Increasing the amount of cheap and renewable wood flour (WF) in traditional wood–plastic composites (WPCs) can effectively enhance the cost performance and competitiveness of WPCs. This strategy aligns with global goals for sustainable and efficient resource use and carbon neutrality. In this study, ultrahigh-filled WF–polyethylene composites (UWFPEs, WF content >70 wt %) were prepared using maleic anhydride grafted polyethylene (MAPE) as an interface compatibilizer through hot pressing. Increasing the WF content can raise the internal energy consumption of the system under dynamic conditions, weaken water absorption resistance, and reduce melt fluidity, while also improving the creep resistance of the system. The MAPE-compatibilized UWFPEs exhibited high interfacial bond strength, significantly enhancing mechanical strength. When the WF content was 80 %, the bending and tensile strengths increased by 137.7 % and 152.1 %, respectively. When the WF content reached 90 %, the bending and tensile moduli further increased by 28.9 % and 22.1 %, respectively. The effective interfacial combination and improved uniformity of the architecture significantly enhanced the water resistance, dimensional stability, and creep resistance of UWFPEs. The solid-like properties of the UWFPEs were demonstrated using frequency scanning tests conducted at a strain of 0.01 %. The experimental results of this study provide reliable theoretical guidance for the practical production and application of UWFPEs.
Coal fly ash, a by-product of coal combustion in thermal power plants, offers valuable opportunities for reuse in construction and material engineering. This study explores the thermal behaviour of fly ash samples collected from different sections of the REK Bitola Power Plant. Thermal characteristics of the fly ashes obtained from hot stage microscopy revealed distinct transformation stages, including sintering, softening, and melting intervals. X-ray fluorescence analysis was employed for determination of the chemical composition, while sieve analysis was used for investigation of granulometry of the materials. The physical and chemical characteristics of the ashes, particularly their grain size and content of silica, alumina, calcium oxide, and iron oxide play a crucial role in determining their response to heat. These findings help guide more effective use of fly ash in environmentally friendly applications, supporting waste reduction and promoting sustainable practices.
High stress and multi faults lead to rising burst frequency in deep coal mine. Though backfilling mining serves as the most straightforward method for stress-decreasing and burst-preventing, it fails to eliminate coal burst completely. In order to decrease the influence of coal burst on safety mining of deep-buried seam with bursting liability, stress surge and drop mechanisms emerging in backfilling panel are studied with field measurement, theoretical analysis and laboratory test, and destressing effect of roof pre-blasting and large borehole drilling methods is analyzed. High stress, multi faults, width-changing pillar and mining disturbance leads to the emergence of stress concentration, stress surge and stress drop phenomenon in backfilling panel, but the concentration coefficient is smaller than 2.0. At the normal region, influence range reaches 30 m. It increases to 50 m when fault influence is considered and the value grows to 70 m if both fault and pillar influences are added to the panel. Fault activation and rock failure results in sudden release of strain energy, the mechanisms underlying the transition between strain energy and kinetic energy as well as dynamic stress wave are revealed. Note transition ratio reaches 17%. The superposition between dynamic stress wave and static stress field leads to sudden change in mining induced stress. Surrounding rock presents consolidation hardening behavior if it fails before load superposition, resulting in stress surge. Brittle caving behavior emerges if surrounding rock transits from intact into broken state, leading to stress drop. If surrounding rock still keeps intact after stress superposition, it presents elastic rebound behavior and experiences dynamic load. Large-scale rupture of hard roof is not observed due to supporting effect provided by backfilling materials and thus, microseismic energy associated with single event is smaller than 105 J. But microseicmic events presents asymmetrical distribution due to fault influences. They present high frequency and low energy mode at maingate side while low frequency and high energy mode is observed at tailgate side. As a result, burst monitoring pre-warning happens two times in the latter roadway and one time is observed in the former one. Hard roof pre-blasting and large borehole drilling methods are used to decrease mining-induced stress. Large-scale blasting fractures are formed in roof strata, which control stress concentration degree and stress increase speed effectively. Thus, coal burst danger is significantly decreased in deep mining.
In order to reduce the concentration of coal dust in open-pit coal mines, reduce and prevent the harm of coal dust, based on the microbial induced calcite precipitation solidification dust technology, the influence of environmental factors（temperature, pH） on the growth of Bacillus pasteuri was explored, and the effects of bacterial concentration, cement concentration and nutrient solution concentration on the solidification effect were evaluated by measuring the production of CaCO3. Through the experiment, the matrix analysis method was used to optimize the proportion of Bacillus pasteuri microbial dust suppressant and a new type of high-efficiency and environmentally friendly microbial dust suppressant for mining was proposed. The results show that the suitable culture conditions of Bacillus pasteuri are 30 ℃-35 ℃, pH 7.5, and the microbial dust suppressant is suitable for opencast coal mines under high temperature and moderate alkaline environment; there was a positive correlation between the concentration and the bacterial concentration. With the increase of cement concentration (urea, calcium chloride), the generation amount of CaCO3 increases and then decreases; Bacillus pasteurelli microbial dust suppressant has good permeability, strong wind resistance, water retention, rain resistance and other comprehensive properties; the optimization scheme of the composition ratio of Bacillus pasteuri microbial dust suppressant is: the OD600 value of Bacillus pasteuri bacteria solution is 1, the cementing solution （urea, calcium chloride mixed solution）is 0.5 mol/L, and the nutrient solution is 2 g/L.
The limited hydration capacity and challenges related to delayed expansion prevent fly ash (𝐹𝐴) and 𝑀𝑔𝑂 expansive additive (𝑀𝐸𝐴) from being used significantly. Nonetheless, utilizing these two procedures in hydraulic mass concrete applications is a frequently used approach that yields favorable outcomes. To construct and assess machine learning-based algorithms to assess the volume expansion (𝑉𝑒) of cement paste, which consists of 𝐹𝐴 and 𝑀𝐸𝐴, 170 experimental findings from published studies are employed. A novel approach called least square support vector regression (𝐿𝑆𝑆𝑉𝑅) has been developed. The efficacy of 𝐿𝑆𝑆𝑉𝑅 is significantly impacted by its hyperparameters (𝑐 and 𝑔), which were fine-tuned using the Dwarf Mongoose Optimization Algorithm (𝐷𝑀𝑂𝐴) and the Equilibrium Optimization Algorithm (𝐸𝑂𝐴). Based on the results obtained, it can be inferred that there exists a significant potential for both 𝐿𝑆𝑆𝑉𝑅𝐸 and 𝐿𝑆𝑆𝑉𝑅𝐷 models to accurately predict the 𝑉𝑒 of cement paste that incorporates fly ash and 𝑀𝑔𝑂 expansive addition. In the training and testing phases, the Theil inequality coefficient (𝑇𝐼𝐶) values for 𝐿𝑆𝑆𝑉𝑅𝐸 are observed to be 0.0906 and 0.01043, which are comparatively higher than the 𝑇𝐼𝐶 values for 𝐿𝑆𝑆𝑉𝑅𝐷, which are 0.0382 and 0.0044, respectively. By predicting the volume expansion accurately, engineers can adjust the proportions of 𝐹𝐴 and 𝑀𝐸𝐴 to achieve desired expansion properties, improving the durability and stability of concrete structures. Accurate prediction models allow for better control of thermal stresses, reducing the risk of thermal cracking and extending the structure's lifespan.
3C silicon carbide (3C-SiC) has great potential and value for innovated high-precision devices. However, the high hardness make it a daunting task to understand its deformation behavior and anisotropy effect, which impedes its processing and application. In this study, we performed molecular dynamic simulations of nanoindentation to study the deformation behavior and anisotropy effect of 3C-SiC. It is found that the elastic deformation and incipient plastic deformation are orientation-dependent, exhibiting fourfold symmetry, central symmetry and threefold symmetry while indenting on 3C-SiC (010), (110) and (111) surfaces. The dislocations nucleate and propagate due to the high shear stress induced by indentation, which in turn leads to the dissipation of shear stress in the sample. In the plastic stage, the dislocations evolve from embryonic dislocations to ribbon dislocations, and finally to prismatic dislocations. The prismatic dislocation loops are surrounded by stacking faults in {111} planes, most of which are enclosed by four stair-rod dislocations in <110> orientations. Moreover, we find that Thompson tetrahedron is suitable for understanding the anisotropy effect of ceramics with cubic diamond structure, and it is applied to investigate the formation and evolution of dislocations systematically in 3C-SiC. This research is meaningful for understanding the deformation behavior and anisotropy effect of 3C-SiC. The results may provide theoretical support for the processing and application of 3C-SiC.
In contrast with studies such as those on the effect of a single elemental variable on Zn-Al-Mg coatings, Mg/Al is considered a variable parameter for evaluating the microstructure of Zn-Al-Mg coatings in this work, and the combined effect of the two elements is also taken into account. The Mg/Al ratios in the continuous hot-dip plating of low-alumina Zn-Al-Mg coatings were 0.63, 0.75, 1.00, 1.25, and 1.63. respectively, and the microstructures of the different coatings were observed using scanning electron microscopy (SEM). The surface elemental distributions of the coatings were analyzed with energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) analysis to understand the phase distributions of the coatings, which mainly consisted of a zinc monomeric phase, a binary eutectic phase (Zn/MgZn<sub>2</sub>), and a ternary eutectic phase (Zn/Al/MgZn<sub>2</sub>). Statistical calculations of the phase distributions in colored SEM images were performed using ImageJ-win64 software, comparative analysis of the solidification simulation results was carried out with thermodynamic simulation software (PANDAT-2023), and evaluation of the corrosion resistance of the platings was performed using macroscopic cyclic immersion corrosion experiments. The results show that with the increase in the Mg/Al ratio, the binary eutectic phase in the coatings gradually increased, the variation trend of the ternary eutectic phase was not obvious, and the corrosion resistance of the coatings gradually improved.
Oil-rich coal is a special coal resource with a tar yield ≥ 7% and a combination of coal, oil, and gas attributes. It is an important resource and development direction for the clean utilization of coal, and has important scientific value in alleviating the shortage of national oil and gas resources and promoting the breakthrough development of coal chemical industry. There are a large number of tar-rich coal resources in the eastern basin of Xinjiang Uygur Autonomous Region. In order to find out the occurrence and distribution of tar-rich coal, the coal accumulation and occurrence characteristics of tar-rich coal were studied by means of sedimentary environment analysis, proximate analysis of coal, ultimate analysis of coal, and Gray-King assay for coal. The geological block method was used to estimate the resources of tar-rich coal. The results show that the tar-rich coal seams in the Santanghu Basin are mainly distributed in the upper section of the Badaowan Formation (J1b2), the Sangonghe Formation (J1s) and the lower section of the Xishanyao Formation (J2x1), the tar yield is about 13.67%, which is high tar-rich coal. The tar-rich coal seams in the Turpan-Hami Basin are developed in the middle section of the Xishanyao Formation (J2x2), and the tar yield is about 7.6%, which are tar-bearing coal and tar-rich coal. The tar-rich coal in the area is generally characterized by ultra-low to medium-low water content, low to medium-low ash content, medium-high to high volatile content, high tar yield, rich in oil generating components such as vitrinite and lipitnite, low degree of coalification, and formed in the lacustrine-deltaic sedimentary environment. The potential of rich oil coal resources in the study area is large. The resources of tar-rich coal in the Santanghu Basin is estimated to be 67.083 billion tonnes above a depth of 2 000 m, and the resources of tar-rich coal in the Turpan-Hami Basin is estimated to be 41.755 billion tonnes above a depth of 2 000 m, and the average thickness of the coal seams is more than 9 m. In order to effectively utilize the development of oil rich coal resources, the technical assumption of Underground Coal Pyrolysis (UCP) is proposed. The UCP refers to the establishment of heat introduction and product production channels in underground coal seams through petroleum engineering technology. Through artificial heating, coal undergoes in-situ carbonization reactions. The pyrolysis products include tar, gas (CH4, H2, light hydrocarbon C2+, etc.), and water. The carbon element in coal is mainly left underground in the form of semicoke, and the generated carbon dioxide can be used to drive oil in the Santanghu and Turpan-Hami Basins. The remaining carbon dioxide can be buried in-situ using the semicoke layer. The UCP achieves a clean conversion of coal resources through “hydrogen extraction and carbon retention”, which is expected to become a technical direction for the low-carbon green development of tar-rich coal.