Surface Technology (表面技术)•2026•DOI: 10.16490/j.cnki.issn.1001-3660.2026.08.008
Cavitation erosion and wear failure critically limit the service life of flow-passing components such as pump impellers, turbine blades, and propeller systems subjected to high-speed liquid impact and cyclic flow-induced stresses. This work aims to design a high-performance surface coating with enhanced hardness, wear resistance, and cavitation erosion resistance by tailoring the Nb content in a CoCrNi medium-entropy alloy (MEA) system. CoCrNiNbx (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2) coatings were fabricated on 316L stainless-steel substrates with an FL020 fiber laser under identical processing parameters. The effect of Nb addition on the phase constitution, microstructure, mechanical properties, tribological behavior, and cavitation performance of the coatings was comprehensively investigated to determine the optimal composition for balanced mechanical and anti-erosion properties. Phase analysis by X-ray diffraction (XRD) showed that increasing Nb content promoted a transition from a single face-centered cubic (FCC) solid solution to a dual FCC + hexagonal close-packed (HCP) phase structure. The emergence and growth of the Nb-rich HCP phase were accompanied by pronounced lattice distortion and precipitation strengthening. Microstructural characterization using field-emission scanning electron microscopy (SEM) combined with energy-dispersive spectroscopy (EDS) revealed that Nb preferentially segregated along interdendritic regions, where fine HCP-phase precipitates gradually formed a semi-continuous strengthening network. Electron backscatter diffraction (EBSD) analysis further quantified grain size and phase distribution. The average microhardness of the coatings initially increased and then decreased with increasing Nb molar ratio x, peaking at 689 HV0.1 for x = 0.6, approximately 3.7 times that of the substrate. Wear performance followed the same trend. Cavitation erosion tests demonstrated that the CoCrNiNb1.0 coating exhibited optimal cavitation erosion resistance, with mass loss significantly lower than that of the 316L substrate, achieving an order-of-magnitude improvement. The optimal Nb addition (x = 0.6–1.0) balances strength and toughness, significantly enhancing the wear and cavitation erosion resistance of CoCrNi-based MEA laser-cladded coatings. This study provides experimental evidence and process references for engineering applications of CoCrNi-based MEA coatings in high-flow-velocity liquid impact environments.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2026•DOI: 10.1016/j.ijmst.2026.01.003
Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.
New Carbon Materials (新型炭材料)•2025•DOI: 10.1016/S1872-5805(NCM2026-41-03-05)
Carbon/carbon (C/C) composites are ideal materials for electromagnetic interference (EMI) shielding and thermal management in the aerospace field because of their low density. However, traditional C/C composites primarily rely on repeated densification to increase their EMI shielding effectiveness (SE), which not only increases density but also involves lengthy preparation cycles. We have constructed a unidirectional (1D) C/C composite using a matrix of mesophase pitch-derived carbon and graphite flakes, reinforced with mesophase pitch-based carbon fibers. Using a one-step consolidation process produced by spontaneous assembly during heating, the open pores and a continuous conductive network give the composite an EMI SE of up to 83.97 dB in the 8.2–12.4 GHz (X-band). The material also has a thermal conductivity of 191.84 W·m−1·K−1 and an electrical conductivity of 6.50 × 104 S·m−1 along the fiber direction, together with a flexural strength exceeding 100 MPa, while having a bulk density of only 1.01 g·cm−3. This work therefore presents a short-cycle fabrication strategy for low-density C/C composites that integrate high EMI SE, efficient thermal management, and good mechanical properties.
Journal of Semiconductors (半导体学报 - 中国科学院半导体研究所)•2025•DOI: 10.1088/1674-4926/25010005
A 4H-SiC superjunction (SJ) MOSFET (SJMOS) with integrated high-K gate dielectric and split gate (HKSG-SJMOS) is proposed in this paper. The key features of HKSG-SJMOS involve the utilization of high-K (HK) dielectric as the gate dielectric, which surrounds the source-connected split gate (SG) and metal gate. The high-K gate dielectric optimizes the electric field distribution within the drift region, creating a low-resistance conductive channel. This enhancement leads to an increase in the breakdown voltage (BV) and a reduction in the specific on resistance (Ron,sp). The introduction of split gate surrounded by high-K dielectric reduces the gate−drain capacitance (Cgd) and gate−drain charge (Qgd), which improves the switching characteristics. The simulation results indicate that compared to conventional 4H-SiC SJMOS, the HKSG-SJMOS exhibits a 110.5% enhancement in figure of merit (FOM, FOM = BV2/Ron,sp), a 93.6% reduction in the high frequency figure of merit (HFFOM) of Ron,sp·Cgd, and reductions in turn-on loss (Eon) and turn-off loss (Eoff) by 38.3% and 31.6%, respectively. Furthermore, the reverse recovery characteristics of HKSG-SJMOS has also discussed, revealing superior performance compared to conventional 4H-SiC SJMOS.
Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2025•DOI: 10.1016/S1003-6326(25)67033-6
The phase composition at the slag−iron interface and the distribution behavior of titanium, vanadium, chromium and silicon between hot metal and Ti-bearing electric furnace slag were thoroughly explored. The basicity range for the anosovite phase region was defined by using a phase diagram and a minimum smelting temperature was set at 1540 °C. Thermodynamic calculations demonstrate that the activities of TiO2 and SiO2 in the slag decrease with increasing basicity, while those of V2O3 and Cr2O3 increase. Similarly, the activities of [Ti] and [Si] in the molten metal decrease, while those of [V] and [Cr] rise with increasing basicity. As basicity increases, the distribution ratios, LTi and LSi decrease, whereas LV and LCr increase. Significantly, the recovery efficiencies of vanadium and titanium are improved with higher basicity. The primary phases identified in the slag include anosovite, diopside, and titanium spinel. However, when the basicity exceeds 0.8, the formation of the perovskite phase becomes less favorable, suggesting that basicity should be maintained at or below 0.8.
Transactions of Nonferrous Metals Society of China (中国有色金属学报)•2025•DOI: 10.1016/S1003-6326(25)66953-6
A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface, which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate. The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate, which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing. In addition, the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing, which has a large effect on the texture components of the substrates near the corrugated interface. The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong “mechanical gearing” effect. Moreover, the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.05.002
Coal pillars are critical supporting structures between underground coal gasification gasifiers. Its bearing capacity and structural stability are severely threatened by high-temperature environments. To elucidate the high-temperature deterioration mechanism of coal pillars at multiple scales, coal strength features as a function of temperature were investigated via uniaxial compression and acoustic emission equipment. The pyrolysis reaction process and microstructure evolution were characterized via X-ray diffractometer (XRD), scanning electron microscope (SEM), thermogravimetric (TG), Fourier transform infrared spectroscopy (FTIR), and computed tomography (CT) tests. Experimental results reveal a critical temperature threshold of 500 °C for severe degradation of the coal bearing capacity. Specifically, both the strength and elastic modulus exhibit accelerated degradation above this temperature, with maximum reductions of 45.53% and 61.34%, respectively. Above 500 °C, coal essentially undergoes a pyrolysis reaction under N2 and CO2 atmospheres. High temperatures decrease the quantity of O2-based functional groups, growing aromaticity and the degree of graphitization. These changes induce dislocation and slip inside the coal crystal nucleus and then lead to deformation of the coal molecular structural units and strain energy generation. This process results in a great increase in porosity. Consequently, the stress deformation of coal increases, transforming the type of failure from brittle to ductile failure. These findings are expected to provide scientific support for UCG rock strata control.
Int. Journal of Mining Science and Technology (采矿与安全工程)•2025•DOI: 10.1016/j.ijmst.2025.06.009
Borehole pressure relief helps prevent rock bursts. However, this may change the physical and mechanical properties of the surrounding rock, affect the variation of the plastic zone of the roadway, and lead to the failure of roadway support, thus threatening the safety of the roadway. In this paper, the variable angle shear test of drilled specimens under the action of static and dynamic loads is used to study the evolution of mechanical parameters of the specimens and their influence on the plastic zone of the surrounding rock. The shear strength decreases linearly with the increase of drilling diameter. With the increase of pre-static load level and dynamic load amplitude, the cohesion first increases and then decreases, and the internal friction angle decreases. Moreover, the shear failure surface changes from rough to smooth. The reasons include that the static load enhances the tooth cutting effect and the repeated friction of cracks caused by the dynamic load. Borehole pressure relief leads to an increase in the radius of the plastic zone of the surrounding rock following a quadratic function. The research results of this paper provide a theoretical basis for designing drilling unloading parameters and supporting parameters for rock burst roadways.