- 中国科学引文数据库(CSCD)核心期刊
- 中国核心期刊
- 文摘与引文数据库(Scopus)
- 剑桥科学文摘(CSA)
- 英国INSPEC数据库
Continuous fiber-reinforced SiC composites have shown significant potential in aerospace applications due to their lightweight, high-temperature resistance, and corrosion tolerance. The introduction of continuous fibers improves the brittleness of the ceramic matrix, while additive manufacturing (AM) provides new opportunities for designing and fabricating complex components. Research on additive manufacturing of continuous fiber-reinforced SiC composites is still in its early stage, making a systematic review of recent progress highly valuable. This work summarizes the latest advances in three representative AM techniques: fused deposition modeling (FDM), direct ink writing (DIW), and automated fiber placement (AFP), with a comparative analysis of domestic and international studies. The results indicate that FDM using continuous fiber filaments achieves high forming accuracy but has an upper limit on fiber volume fraction; DIW suffers from fiber aggregation and insufficient interfacial protection due to in-situ infiltration; AFP with continuous fiber sheets offers high fiber content and fracture toughness, though infiltration remains incomplete. Regarding fiber reinforcement, future research should focus on high-performance multi-series fibers, specifically targeting fiber protection and interfacial regulation. In terms of defect control, synergistic optimization of printing strategies and ceramic process parameters will be employed to achieve high forming precision, ultimately enabling the additive manufacturing of high-performance SiC composite components.
Precision casting is the primary manufacturing process for core components of high-end critical equipment such as turbine blades for aero-engines and gas turbines, which directly determines the quality and performance of components and affects the efficiency and reliability of high-end equipment. Nevertheless, the precision casting process still faces challenges including casting defect control, dimensional accuracy and deformation control, and casting quality inspection. The rapid advancement of artificial intelligence technology offers new technical approaches for investment-casting process optimization and casting inspection. This paper systematically reviews the research progress of artificial intelligence in the field of investment casting. It mainly covers the applications of artificial intelligence in the preparation of key intermediate products including ceramic cores, wax patterns, and ceramic shells; the advances of artificial intelligence in assisting defect-performance control and dimensional control during casting solidification; as well as its applications in casting inspection, involving surface and internal defect detection, metallographic microstructure analysis, and other aspects. Finally, the advantages and challenges of applying artificial intelligence to precision casting processes and casting inspection are summarized, and future research directions are prospected: (1) promote the evolution of artificial intelligence from empirical prediction for individual process links toward unified full-process and multi-scale modelling; (2) drive the transformation of investment casting from independent shape control or performance control toward coordinated shape-performance regulation; (3) develop physics-informed neural networks tailored for the investment-casting process; (4) realize the transition of investment-casting processes from offline optimization to autonomous closed-loop control; (5) large-language models provide new technical pathways for the intelligent development of precision casting.
This study systematically investigates the effects of the constrained aging process on the microstructure, martensitic transformation, and functional properties of Ni-48.85Ti-0.3Cr shape memory alloys using DSC, TEM and DMA. The experimental findings reveal that following constrained aging, directionally distributed Ni4Ti3 phase is discretely precipitated within the alloy matrix. Under the condition of 400 ℃/100 MPa, extending the constrained aging time leads to a significant increase in the length of Ni4Ti3 phase. When subjected to the process of 1 h/100 MPa, raising the temperature not only increases the length and width of the precipitated phases simultaneously but also transforms their morphology from fine granular to larger lenticular, resulting in a corresponding improvement in the aspect ratio. At 400 ℃/100 MPa, when the constrained aging time is prolonged from 0.5 h to 2 h, both the R transformation and B19′ martensitic transformation temperatures rise. This can be attributed to the precipitation of Ni4Ti3 phase, which reduces the Ni element content in the matrix. Under the condition of 1 h/100 MPa, aging at 400 ℃ enlarges the size of the precipitated phases and weakens their strengthening effect on the matrix, thereby facilitating the increase in the transformation temperature. At 500 ℃, the transformation process shifts from a two-step to a three-step, with A→R→M1 transformation occurring in the regions near the precipitated phases and A→M2 transformation in the regions far from them. Isothermal entropy change tests indicate that at 400 ℃/1 h, the isothermal entropy change decreases as the constrained stress increases. At 400 ℃/100 MPa, the isothermal entropy change initially increases and then decreases with the extension of the aging time. Similarly, at 1 h/100 MPa, the isothermal entropy change also exhibits a trend of first increasing and then decreasing as the aging temperature rises.
GH3230 superalloy is widely used in the fields of aero-engine and nuclear industry. Due to its extensive application, the accurate assessment of service life of its components highly relies on the precise prediction of uniaxial tensile properties and stress rupture life. This paper focuses on investigating uniaxial tensile properties of this superalloy at different temperatures, as well as its stress rupture life under various combinations of temperature and stress. Correspondingly, the R-O constitutive model and the Chaboche constitutive model are established to describe the tensile behaviour of the alloy, while the isothermal line extrapolation method and the L-M parameter model are developed for predicting its stress rupture life. The results indicate that in terms of predicting uniaxial tensile properties, compared to the Chaboche constitutive model, the R-O model can only reasonably predict the stress near the yield point, showing a significant deviation in the overall prediction trend of the stress-strain curve. In contrast, the Chaboche constitutive model can more effectively describe the tensile behaviour of the GH3230 superalloy, with fitting correlation coefficients close to 0.9 at most test temperatures. Regarding the prediction of stress rupture life, both the isothermal line extrapolation method and the L-M method demonstrate high prediction accuracy. These models are capable of providing reasonable predictions for the stress rupture life of the superalloy under different service conditions.
During welding thermal cycles, magnesium alloys are highly susceptible to grain coarsening and structural changes of precipitates, leading to microstructural damage and subsequently deteriorating the performance of welded joints. Consequently, mitigating the strength degradation of magnesium alloys during welding has attracted considerable research attention in the field of magnesium alloy processing. In this study, an ultrasonic vibration-assisted solid-state joining process is employed to join a Ce-containing rare-earth magnesium alloy, and the microstructural evolution and strengthening mechanisms of the joints are systematically investigated. The results indicate that the acoustic plasticity and thermal effects induced by ultrasonic vibration promote intense dynamic recrystallization at the contact interface, resulting in significant grain refinement within the ultrasonic-affected zone, with grain sizes reduced from 250 μm in the base metal to 10-30 μm in the joint region. Simultaneously, the high-frequency mechanical shearing generated by ultrasonic vibration fragments coarse precipitates into uniformly distributed micro- and submicro-sized particles, thereby significantly enhancing precipitation strengthening. In addition, the segregation of rare-earth element Ce at the grain boundaries leads to the formation of thermally stable phases, which effectively pin grain boundaries and suppress dislocation motion, thereby mitigating microstructural degradation during the joining process. Mechanical testing demonstrates that the synergistic effects of grain-refinement strengthening, dispersion strengthening, and rare-earth strengthening enable the joint to achieve a lap-shear strength of 194.9 MPa, equivalent to 92.4% of the base metal strength. Additionally, the fracture mode transitions from interfacial brittle fracture to matrix ductile fracture. The findings provide theoretical basis and technical guidance for the development of low-damage, highly reliable joining technologies for rare-earth magnesium alloys.
In order to satisfy the requirements of civil aircraft crashworthiness, a method of using aluminium foam as fuselage section filling material is proposed, and on this basis the energy absorption characteristics and impact response characteristics of fuselage structures filled with different relative densities of aluminium foam are investigated. Firstly, quasi-static and medium strain rate (0.001～100 s–1) compression tests are carried out on aluminium foams with low, medium, and high relative densities, using an electronic universal testing machine and high-speed power loading systems. Secondly, an equivalent finite element model for different relative densities of aluminium foam is established and the validity of the model is verified by comparing the results of the model analysis with the experiments. Finally, the aluminium foam equivalent model is applied to the analysis of civil aircraft crashworthiness and the damage pattern, energy absorption, and acceleration time course of the fuselage section in the passenger cabin floor after placing aluminium foam of different relative densities are analyzed. The results show that the platform stress and volume specific energy absorption of the aluminium foam increase with increasing relative density, while the opposite is true for densified strain. The addition of aluminium foam-filled energy-absorbing structures better balances the energy absorption rate of the fuselage frame components than classic frame construction. At the same time, as the relative density increases, the energy absorption of the aluminium foam gradually increases and the peak acceleration of the cabin floor decreases, indicating that high relative density aluminium foam has a stronger cushioning and energy absorption properties than low and middle relative density aluminium foam, and these provide theoretical support for the application of aluminium foam to the crashworthiness design of civil aircraft.
The mechanical properties of ceramic matrix composite structures are predominantly influenced by their micro-scale damage evolution features, given that material failure fundamentally stems from the initiation and progression of microstructural damage. To precisely characterize the micro-damage behavior of composites, multi-scale analysis methods grounded in parameter cross-scale transfer have been extensively employed in the study of composite mechanical properties. Nevertheless, traditional multiscale methods are plagued by low computational efficiency and a geometric increase in computational effort with nested scales, rendering them ill-suited for real-time engineering applications. To tackle this issue, this work puts forward a concurrent multiscale modeling method based on self-consistent clustering analysis. This method utilizes clustering to reduce the dimensionality of the microscale stress/strain field. It substitutes full-scale microscale finite element computations with homogenized response results, thereby substantially enhancing the efficiency of multiscale computations. Numerical results reveal that for both unidirectional and woven composite material cases, the proposed method achieves an overall improvement in computational efficiency of approximately one order of magnitude (10-15 times faster) while keeping computational errors below 3%. By effectively cutting down on computational costs while maintaining high accuracy, this approach provides new insights and technical means for efficient damage analysis and life prediction of composite structures.
Ultra-high temperature ceramics (UHTCs) are regarded as highly promising materials for aerospace applications due to their exceptional thermal and mechanical stability under harsh environmental conditions. In this study, to further enhance the performance of UHTCs across a broad temperature range, multiphase ceramics are fabricated through a combination of in-situ reaction and hot-pressing techniques, utilizing TaSi2, ZrSi2, B4C, and C as raw materials. Subsequently, the microstructure, micromechanical properties, and oxidation resistance of the prepared ceramics are thoroughly investigated. The results reveal that the ZrB2-TaB2-SiC multiphase ceramic is formed at 1200 ℃. As the temperature increasing to 1500 ℃, the ZrB2-TaB2-SiC ceramic undergoes an in-situ solid-solution reaction, transforming into (Zr0.5Ta0.5)B2-SiC. In terms of mechanical properties, the hardness values are 12.59 GPa for ZrB2-TaB2-SiC and 15.11 GPa for (Zr0.5Ta0.5)B2-SiC, respectively. Similarly, the fracture toughness values are 3.66 MPa·m1/2 for ZrB2-TaB2-SiC and 5.89 MPa·m1/2 for (Zr0.5Ta0.5)B2-SiC, respectively. Thermogravimetric analysis demonstrates that the (Zr0.5Ta0.5)B2-SiC solid-solution multiphase ceramics exhibit outstanding oxidation resistance. Specifically, the mass gain is only 0.48 mg/cm2 when the temperature reaches up to 1600 ℃. The mechanism underlying this excellent oxidation resistance can be attributed to synergistic effect of multiphase oxides, which stabilizes oxidation film and reduces diffusion rate of oxygen.
To address the issues of volatile oxide scale and insufficient oxidation/ablation resistance of monolithic SiC ceramics in extreme environments, this study employs polysiloxane as a ceramic precursor and titanium acetylacetonate (TiO(acac)2) as a modifier. SiC/TiC composite ceramics are prepared via a precursor conversion method combined with spark plasma sintering. The cross-linking and curing mechanism of the precursor, as well as the high-temperature pyrolysis behavior, are systematically investigated, and the influence mechanism of Ti doping on the oxidation/ablation resistance of the composite ceramics is elucidated. The results show that Ti promotes precursor cross-linking through the formation of Si―O―Ti bonds, achieving a ceramic yield as high as 79.18%. When the TiO(acac)2 mass content reaches 20%, the TiC mass content in the composite increases to 19%, and the densification of the sintered ceramic is significantly improved. Oxy-propane ablation tests at 1600 ℃ demonstrate that the 20% modified sample exhibits greatly enhanced ablation resistance, with linear and mass ablation rates of 0.017 μm/s and −0.140 mg/s, respectively. This superior ablation resistance is attributed to the formation of a continuous composite oxide layer consisting of TiO2 and SiO2, which suppresses the volatilization of SiO2 and further oxygen diffusion.
Ti48Al2Cr2Nb-0.5GO-xTiB2 (x is mass fraction/%) composites synergistically reinforced by TiB2 and Ti2AlC are fabricated via spark plasma sintering. The effects of TiB2 content on the microstructural evolution and mechanical properties of the composites at room and high temperatures are systematically investigated. The results reveal that the addition of TiB2 significantly refines the lamellar colony size and promotes the transformation of the matrix microstructure from fully lamellar to duplex microstructure, which effectively improves the microstructural homogeneity of the material. The composite with 0.3%TiB2 exhibits optimal comprehensive mechanical properties, with a compressive strength of 1870 MPa and compressive strain of 27.5% at room temperature, respectively. When the TiB2 content is 0.2%, the high-temperature tensile strength at 850 ℃ is approximately 500 MPa, representing a 32.5% improvement compared with the base alloy. Micromechanical analysis demonstrates that the enhanced performance mainly originates from grain refinement strengthening and second-phase strengthening jointly induced by TiB2 and Ti2AlC. During deformation, the reinforcing phases cooperatively regulate plastic deformation behavior and fracture processes through mechanisms including microcrack deflection, interfacial debonding, and stress redistribution, thus optimizing the strength-ductility balance of the material.
Composite rotor blade becomes one of the important components in the aerospace and energy industries, owing to its advantages of lightweight, high specific strength and modulus, and tunable mechanical properties. Determining the effects of material parameters and layup on structural load-bearing capacity is valuable for engineering application. With energy method, a theoretical model for strength evaluation, stiffness analysis, and layup optimization of this structure are proposed. Based on Rayleigh-Ritz method, theoretical models about the simulating specimen for composite rotor blade under different loading conditions are established, including the blade solely under centrifugal force and the blade under combined centrifugal force and uniform pressure. The theoretical model is verified by the finite element method (FEM). And a higher order of the trial function induces higher prediction accuracy of the model. Finally, the effects of different layups on the strength and stiffness of the rotor blade simulator with ply drops are evaluated with this model. The results show that the prediction error of the theoretical model in radial deformation is lower than 6%. And for transverse deformation prediction, the error is no higher than 15%. The theoretical analysis aligns well with simulation results in predicting stress distribution. Besides, it shows that the layup significantly influence the mechanical performance of the structure. The deformation in x-direction of the structure with [0]n layup is the smallest, followed by the structure with [0/90]ns layup and [±30]ns layup. The deformation in x-direction of the structure with [±45]ns layup is the largest. The increase in proportion of 0° plies improves the structural stiffness. As for stress along the principal material axes, the structures with [0]n, [±30]ns and [±45]ns layups have similar magnitude, which are smaller than that of the structure with [0/90]ns layup. The theorical model proposed in this paper provides a method for efficiently evaluating the mechanical properties of the composite rotor blade. Compared to traditional method, this model can shorten the design period and improve the efficiency, which is helpful for optimal design of composite power components.
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