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2026 Vol. 31, No. 4
Published: 2026-08-15
Engineering and Technology
Theoretical Research
 
       Theoretical Research
321 Thermodynamic study of the Cu-Mg-Y system
YAN Jingzhe, LIU Shuhong, DU Yong
DOI: 10.19976/j.cnki.43-1448/TF.2026042
Thermodynamic study of the Cu-Mg-Y system serve as the foundation for constructing the Al-Cu-Mg-Y quaternary database, designing long-period stacking ordered (LPSO) strengthened Mg alloys, and optimizing the glass-forming ability (GFA) of Mg-based amorphous alloys. Based on literature data, the present work re-optimized the thermodynamic parameters of the Cu-Mg-Y system using the calculation of phase diagram (CALPHAD) method. The substitutional solution model was employed to describe the liquid phase, and a general model for LPSO structures was adopted to characterize the τ11 phase (14H). The calculated isothermal sections at 673, 573, and 723 K, vertical sections at 17.2% Cu, 7.2% Y, and 10% Y (mole fraction), as well as the liquidus projection, all agree well with experimental data. At 673 K, the solubility of Y in the τ11 phase ranges from 7.96% to 8.69% (mole fraction), and the invariant reaction Liquid+αMg↔τ11+CuMg2 is determined to occur at 715 K. Furthermore, Scheil non-equilibrium solidification simulations were carried out for two typical high-GFA alloys, Cu12.8Mg80.4Y6.8 and Cu36.9Mg55.6Y7.5 (mole fraction, %), clarifying their solidification paths and phase precipitation behavior, and providing a thermodynamic basis for the compositional design of alloys in this system.
2026 Vol. 31 (4): 321-332 [Abstract] ( ) HTML (0 KB)  PDF  (709 KB)  ( )
333 Acoustic performance of acoustic liner for thermoacoustic oscillation muffler of additive manufacturing heavy-duty gas turbine
ZHENG Runchi, WANG Qingmei, LI Zhengyang, DONG Yisheng, GUI Wanyuan
DOI: 10.19976/j.cnki.43-1448/TF.2026015
In this study , 316L stainless steel thermoacoustic oscillation muffler liners with different pore structure parameters were fabricated via laser powder bed fusion technology. The acoustic properties were examined in the frequency range below 2 500 Hz, with a focus on transmission loss, combining COMSOL finite element simulations and experimental methods. The results show that below 1 500 Hz, simulation results using the narrow area acoustics and internal perforated plate boundary conditions align well. In the frequency range of 1 500~2 500 Hz, discrepancies arise due to enhanced thermal-viscous effects. When the total perforation area remains constant, the shape of the perforation has little influence on transmission loss. Increasing the pore diameter shifts the peak transmission loss toward lower frequencies and increases its value. When the number of pores is less than 120, increasing the number of pores shifts the peak to higher frequencies and increases its value; however, increasing the number beyond 120 leads to a reduction in the peak value. The integration of additive manufacturing with simulations provides technical support for the optimization of mufflers used for thermoacoustic oscillation control in gas turbine combustion chambers.
2026 Vol. 31 (4): 333-341 [Abstract] ( ) HTML (0 KB)  PDF  (574 KB)  ( )
       Engineering and Technology
342 Fabrication and high-temperature energy storage performance of ZIF-8/PEI dielectric composites
YANG Chenchen, LI Xiaona, WANG Fan, LUO Hang, ZHANG Dou
DOI: 10.19976/j.cnki.43-1448/TF.2026020
To address the issue of deteriorated energy storage performance in traditional polyetherimide (PEI) dielectrics under high-temperature conditions, this work prepared zeolitic imidazolate framework-8 (ZIF-8) with highly uniform morphology via a mild precipitation method. Dielectric composites with varying filler contents were fabricated by incorporating ZIF-8 as a functional filler into the PEI matrix. Scanning electron microscope, impedance analyzer, high-temperature dielectric spectrometer, and ferroelectric analyzer were employed to investigate the microstructure, dielectric properties, and high-temperature energy storage performance of ZIF-8/PEI dielectric composites. The results indicate that when w(ZIF-8)=2%, the composite exhibits optimal energy storage performance. The maximum energy density at room temperature reaches 9.50 J/cm3, representing a 57% improvement over pristine PEI (6.05 J/cm3). Under harsh conditions of 150 ℃ and an energy efficiency exceeding 90%, the composite maintains an energy density of 3.44 J/cm3, significantly outperforming the 1.00 J/cm3 of pristine PEI and demonstrating excellent high-temperature energy storage stability. The enhanced performance of the composite stems from the wide bandgap of ZIF-8, which builds electron migration barrier that effectively suppresses leakage current and inhibits space charge accumulation.
2026 Vol. 31 (4): 342-354 [Abstract] ( ) HTML (0 KB)  PDF  (967 KB)  ( )
355 Self-propagating high-temperature synthesis and characterization of W-Mo alloy nanopowders
ZHANG Baoguang, HUANG Yuanping
DOI: 10.19976/j.cnki.43-1448/TF.2026023
To address the issues of complex processing, high energy consumption, and difficulties in uniformity control associated with existing methods for preparing W-Mo alloy nanopowders, this study proposes a novel combined process of chemical coprecipitation, calcination, and self-propagating high-temperature synthesis. Using ammonium paratungstate and ammonium molybdate as raw materials, a composite oxide precursor with a single W0.4Mo0.6O3 solid solution structure was prepared via coprecipitation followed by calcination at 550  ℃, thereby achieving atomic-scale homogeneous mixing of W and Mo elements. The effects of the material ratio on the phase constitution and microstructure of the products obtained by magnesiothermic reduction self-propagating high-temperature synthesis were systematically investigated by scanning electron microscope, energy dispersive spectrometer, X-ray diffractometer, and X-ray photoelectron spectrometer. The results indicate that a fully alloyed single solid-solution phase can be obtained when the mass ratio of the precursor to Mg powder is 1∶1. The addition of an equal mass of NaCl diluent effectively moderates the combustion temperature and mass transfer conditions, inhibits grain growth and particle agglomeration, and enables the successful preparation of crushable W-44Mo alloy nanopowder with an average particle size of approximately 30 nm and uniform composition. This method provides a new approach for the efficient preparation of high-melting-point alloy powders.
2026 Vol. 31 (4): 355-363 [Abstract] ( ) HTML (0 KB)  PDF  (614 KB)  ( )
364 Effects of Hf microalloying on the microstructure and mechanical properties of Al-0.2Zr alloys
SUN Ke, WEI Qirong, YANG Shuchao, WANG Bin
DOI: 10.19976/j.cnki.43-1448/TF.2026027
Al-0.2Zr-(0-0.2)Hf alloys were prepared by casting and thermomechanical processing in this study. Optical microscope, scanning electron microscope, and transmission electron microscope were employed to investigate the effects of the combined addition of Zr and Hf on the microstructure, aging behavior, electrical conductivity, and mechanical properties of the Al-Zr-Hf alloys. The results show that primary Al3(Zr,Hf) precipitates are formed during solidification of Al-0.2Zr-0.2Hf alloy. These phases act as heterogeneous nucleation sites and significantly refine the as-cast grains, reducing the average grain size by 60 μm compared with the Al-0.2Zr alloy. After peak aging at 400 ℃/100 h, a large number of finely dispersed Al3(Zr,Hf) phases (with an average diameter of 28 nm) precipitate in the Al-0.2Zr-0.2Hf alloy. These precipitates possess an L12 structure and are fully coherent with the α-Al matrix. They enhance the strength of the alloy via precipitation strengthening, while simultaneously reducing electron scattering by depleting Zr and Hf solute atoms from the Al matrix. After aging at 400 ℃/300 h, the alloy achieves an optimal comprehensive performance, with a tensile strength of 103 MPa, an elongation of 21%, and an electrical conductivity of 33.3 MS/m.
2026 Vol. 31 (4): 364-376 [Abstract] ( ) HTML (0 KB)  PDF  (1024 KB)  ( )
377 Microstructure and mechanical properties of 321 stainless steel fabricated by laser powder bed fusion
PENG Kerui, HUANG Yang, CHEN Zhongquan, LI Zhiqing, ZHU Dejing, YUAN Tiechui
DOI: 10.19976/j.cnki.43-1448/TF.2026030
321 austenitic stainless steel is widely used in the aerospace and petrochemical industries due to its excellent corrosion resistance. However, conventional manufacturing methods struggle to meet the engineering requirements for the integrated fabrication of its complex structures. In this study, laser powder bed fusion was adopted to fabricate 321 stainless steel. The regulatory laws of laser process parameters on the porosity, formability, and microhardness of the 321 stainless steels were systematically investigated to screen out the optimal forming process parameters. Furthermore, the microstructure, room-temperature tensile properties, and high-cycle fatigue properties of the 321 stainless steels prepared under the optimal parameters were systematically characterized. The results show that the 321 stainless steel fabricated under the optimal process parameters (laser power of 220 W, scanning speed of 800 mm/s, layer thickness of 0.03 mm, and hatch spacing of 0.08 mm) achieves a high relative density of 99.94%. Its microstructure exhibits a typical mixed grain structure composed of columnar and equiaxed grains, with a small amount of retained ferrite (3.5%). The 321 stainless steel possess superior tensile properties, with the yield strength and tensile strength reaching 553 MPa and 662 MPa, respectively, and the elongation being 31.9%. In addition, the fatigue limit of the material attains 530 MPa, and both tensile and fatigue failures follow the ductile fracture mechanism. This study provides an important experimental basis for the process control and engineering service of additively manufactured 321 stainless steel components.
2026 Vol. 31 (4): 377-390 [Abstract] ( ) HTML (0 KB)  PDF  (1224 KB)  ( )
391 Preparation and properties of graphene-reinforced W-30Cu alloy
LIU Jianle, WANG Dezhi, WU Zhuangzhi, LIU Xinli, DUAN Bohua
DOI: 10.19976/j.cnki.43-1448/TF.2026035
Using ammonium metatungstate, copper nitrate, and graphene oxide as raw materials, W-30Cu ultrafine composite powders with different graphene contents were prepared via freeze drying-calcination-reduction process. After formed by pressing, graphene-reinforced W-30Cu alloys were fabricated by sintering in hydrogen atmosphere at 1 050 ℃. The microstructure, mechanical properties, electrical and thermal conductivity of the alloys were systematically investigated. The results show that the mechanical properties, electrical conductivity, and thermal conductivity of the alloys increase first and then decrease with the rising content of graphene. When the mass fraction of graphene is 1%, the comprehensive properties of the alloy reach the optimum through load transfer, grain refinement strengthening and interface strengthening mechanisms. At this condition, the powder possesses high purity and small particle size with uniformly dispersed graphene. The relative density of the alloy is 98.6%, the hardness (HV) is 293.1, the tensile strength is 545 MPa, the electrical conductivity is 49.33 %IACS, and the thermal conductivity is 273.4 W/(m·K).
2026 Vol. 31 (4): 391-400 [Abstract] ( ) HTML (0 KB)  PDF  (838 KB)  ( )
401 Microstructure and wear mechanism of laser cladding AlCoCrFeNiTi0.5 coating
ZHOU Hao, LI Zhuan, ZHAO Yibo, HU Chun
DOI: 10.19976/j.cnki.43-1448/TF.2026033
Soil-engaging components of agricultural machinery commonly suffer from wear failure and short service life under complex service conditions in sandy abrasive soil. Depositing a wear-resistant coating on their surfaces can effectively enhance the surface hardness and prolong the service life of the components. In this study, an AlCoCrFeNiTi0.5 coating was fabricated on the surface of 30MnB5 steel via laser cladding technology. The effects of annealing treatment on the phase composition, microstructure, hardness and wear performance of the coating were systematically investigated. Combined with the laboratory wet sand rubber wheel wear test and annular soil trough-accelerated wear bench test, the wear mechanism and performance regulation mechanism of the coating were revealed. The results show that the as-deposited AlCoCrFeNiTi0.5 coating possesses a dual-phase solid solution structure composed of FCC and BCC phases. After annealing treatment, Laves and σ phases precipitate in the coating, and the microstructure transforms from coarse petal-like morphology to uniform and fine worm-like structure. The average microhardness (HV0.5) of the annealed coating reaches 770.7, which is 10.3% higher than that of the as-deposited coating. The annealing treatment can significantly optimize the wear resistance of the coating. There are only slight ploughing marks on the worn surface, which effectively inhibit the micro-cutting and plastic deformation dominated by abrasive wear. At the same time, the coating can significantly reduce the wear failure of the rotary blade, and the wear degree of the coating is gradiently distributed along the cutting edge of the rotary blade. This study provides a systematic theoretical basis and technical reference for the design and engineering application of high-wear-resistant high-entropy alloy coatings for soil-engaging components of agricultural machinery.
2026 Vol. 31 (4): 401-412 [Abstract] ( ) HTML (0 KB)  PDF  (940 KB)  ( )
413 Enhancement mechanism of one-step exfoliation-fluorination of h-BN powder on high-temperature dielectric energy storage of composites
MA Xiaoqin, YANG Fengyuan, ZHAO Dongxu, XIE Meiling, JIN Xudong, WANG Jian
DOI: 10.19976/j.cnki.43-1448/TF.2026029
To meet the demand of film capacitors under high-temperature extreme conditions, this work employed a powder surface engineering strategy to prepare surface fluorinated boron nitride nanosheet (F-BNNS) via a one-step ultrasonic exfoliation and simultaneous fluorination process. The F-BNNS was dispersed into a polyetherimide (PEI) matrix to fabricate nanocomposite films, and their high-temperature dielectric peformance, high-temperature breakdown strength, and energy storage performance were investigated. The results show that the exfoliation of hexagonal boron nitride (h-BN) and the construction of surface chemical active sites have been achieved in this paper. The incorporation of F-BNNS significantly enhances the high-temperature breakdown strength and energy density, achieving 575 MV/m and 5.01 J/cm3 at 150 ℃, and 501 MV/m and 3.89 J/cm3 at 200 ℃, far superior to pure PEI film and composite film with unmodified BN. The powder surface fluorination engineering introduces a highly electronegative fluorinated layer and deep energy level traps on BNNS, modulating charge transport and energy band structure at the filler-matrix interface, which significantly suppresses leakage current and space charge accumulation at high temperature, offering a new strategy for designing and preparing high-performance high-temperature polymer dielectrics via functional filler densign.
2026 Vol. 31 (4): 413-422 [Abstract] ( ) HTML (1 KB)  PDF  (773 KB)  ( )
423 Microstructure and fracture behavior of graphite-based and carbon fiber-based carbon strips for high-speed railway pantographs
CHEN Xubin, HE Nan, HUANG Shuai, ZHOU Hongli, HUI Dongxu, WU Shengti, WU Tao, FANG Huachan
DOI: 10.19976/j.cnki.43-1448/TF.2026037
To investigate the influence of reinforcement phase configuration on the performance of carbon strips, this study systematically compared the microstructure, mechanical properties, and fracture behavior of graphite- based (pure carbon, metal-impregnated carbon) and carbon fiber-based (C/C, C/C-Cu) strips. The results show that graphite-based strips belong to a discrete particle-type discontinuous load-bearing system. Due to interconnected pores (open porosity of (17.2±0.7)%) and weak interfacial bonding, the pure carbon strip exhibits a bending strength of only (68.2±1.8) MPa and an impact toughness of (0.44±0.02) J/cm2. After metal impregnation, although the electrical resistivity decreases to (2.4±0.6) μΩ·m, the impact toughness increases only slightly to (0.48±0.09) J/cm2 due to the weak Cu/C interface. In contrast, carbon fiber-based strips rely on a three-dimensional continuous fiber skeleton. The C/C strip achieves an electrical resistivity of (22.0±1.5) μΩ·m and an impact toughness of (1.75±0.02) J/cm2. Although the C/C-Cu strip exhibits a low electrical resistivity of (1.5±0.3) μΩ·m due to its dual continuous structure, the thermal expansion mismatch between copper and carbon leads to interfacial microcracks and bundle-type fiber pullout instead of single-fiber toughening, reducing its impact toughness to (1.00±0.14) J/cm2, though it remains significantly superior to graphite-based strips. Regarding fracture mechanisms, graphite-based strips are dominated by intergranular and cleavage brittle fracture. The C/C strip achieves pseudoplastic fracture through interface debonding, fiber pullout, and crack deflection. In contrast, the C/C-Cu strip exhibits quasi-ductile fracture due to partial failure of toughening mechanisms. The introduction of carbon fiber reinforced phase is key to improving impact toughness, with interfacial bonding strength and reinforcement phase dispersion morphology being the core for property regulation.
2026 Vol. 31 (4): 423-438 [Abstract] ( ) HTML (0 KB)  PDF  (1395 KB)  ( )
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