2023年, 第20卷, 第5期 
刊出日期:2023-09-28

  • 全选
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    Superalloy
  • Jia-yan Sun, Rong Yin, Ye-yuan Hu, Yun-xiang Tan, Qing-yan Xu
    《中国铸造》英文版. 2023, 20(5): 365-375. https://doi.org/10.1007/s41230-023-3028-z
    摘要 ( 72 ) PDF全文 ( 38 )   可视化   收藏
    To enhance the accuracy of mechanical simulation in the directional solidification process of turbine blades for heavy-duty gas turbines, a new constitutive model that employs machine learning methods was developed. This model incorporates incremental learning and transfer learning, thus improves the predictive accuracy and generalization performance. To account for the anisotropy of the directionally solidified alloy, a deformation direction parameter is added to the model, enabling prediction of the stress-strain relationship of the alloy under different deformation directions. The predictive capabilities of both models are evaluated using correlation coefficient (R), average relative error (δ), and value of relative error (RE). Compared to the traditional model, the machine learning constitutive model achieves higher prediction accuracy and better generalization performance. This offers a new approach for the establishment of flow constitutive models for other directionally solidified and single-crystal superalloys.
  • Peng Peng, Zi-jie Liu, Yuan-li Xu, Xu-dong Zhang, Zhi-kun Ma, Jia-tai Wang
    《中国铸造》英文版. 2023, 20(5): 376-386. https://doi.org/10.1007/s41230-023-2118-2
    摘要 ( 47 ) PDF全文 ( 28 )   可视化   收藏
    The effects of Ta content (2.72wt.%, 3.10wt.% and 4.00wt.%) on the solidification characteristics and mechanical properties of directionally solidified DZ411 Ni-based superalloys were investigated. It is found that the content of Mo decreases with the increase of Ta in liquid phase after directional solidification, indicating the addition of Ta can reduce the element segregation in alloys. The primary and secondary dendrite arm spacings (PDAS and SDAS) of the DZ411 alloy increase with the addition of Ta, which are consistent with the models by Hunt and Wagner. The increase of PDAS and SDAS can provide enough space for the growth of tertiary dendrite arms, which hinders the growth of unfavorably oriented primary dendrites. As a result, the addition of Ta facilitates the growth of favorably oriented dendrites. More MC carbides and γ-γ’ eutectics are formed in the interdendritic regions, which is attributed to the segregation of Ta in the liquid phase. Furthermore, the degree of supersaturation of W, Mo in γ matrix increases with the increase of Ta, thus, the addition of Ta promotes the formation of TCP phase. The addition of Ta also increases the microhardness in both the primary dendrite and interdendritic regions of the alloy, and the microhardness of the primary dendrite is closer to that in interdendritic regions with the increase of Ta.
  • Wen-jun Dong, Qiao-lei Li, Tian-ci Chen, Ming-ke Zou, Jing-jing Liang, Li-rong Liu, Hui Mei, Jin-guo Li
    《中国铸造》英文版. 2023, 20(5): 387-394. https://doi.org/10.1007/s41230-023-2122-6
    摘要 ( 46 ) PDF全文 ( 33 )   可视化   收藏
    Ceramic cores are the key intermediate components of hollow blades for aero-engine. Conventional processes, such as hot-press molding and gel film casting, face difficulties in fabricating complex-structured ceramic cores due to the complexity of moulds and long process cycles. Stereolithography 3D printing provides a new idea for the fabrication of complex-structured ceramic cores. The effect of sintering temperature on open porosity, bulk density, weight loss rate, shrinkage rate, flexural strength and microstructure of the Al2O3-based ceramic core doped with 10vol.% polysilazane (PSZ) was studied. The sintering mechanism of PSZ-reinforced ceramic cores was analyzed. Results show that the optimum sintering temperature of PSZ-reinforced ceramic cores is 1,450 ℃. At this temperature, the open porosity of the ceramic core is 36.60%, bulk density is 2.33 g·cm-3, weight loss rate is 22.11%, shrinkage rate along the X, Y, Z directions is 5.72%, 5.01%, 9.61%, respectively; the flexural strength is 28.794 MPa at 25 ℃ and 13.649 MPa at 1,500 ℃. Properties of 3D printing PSZ-reinforced ceramic cores can meet the casting requirement of superalloy hollow blades, which is expected to promote the industrial application of 3D printing complex structure ceramic cores.
  • Zhi-hong Jia, Chen-yang Li, Wen-xiang Jing, Xiang-feng Liang, Ze-kun Zhang, Jia-le Xiao, Yu-tao Zhao
    《中国铸造》英文版. 2023, 20(5): 395-402. https://doi.org/10.1007/s41230-023-2117-3
    摘要 ( 53 ) PDF全文 ( 28 )   可视化   收藏
    The evolution of microstructure and formation mechanism of incipient melting microstructure of DD5 single crystal superalloy during solution heat treatment were studied by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and energy dispersive spectroscopy (EDS). The solidus and liquidus of single crystal alloy were obtained by differential scanning calorimetry (DSC). Results show that the mosaic-like eutectic and fan-like eutectic are dissolved at first, and the coarse γ' phase is dissolved later during the solution heat treatment of 1,390 ℃/2 h+1,310 ℃/4 h+1,320 ℃/10 h + air cooling (AC). The composition segregations of Al, Ta, W and Re are 0.99, 0.96, 1.04 and 1.16, respectively, which close to 1. The incipient melting is caused by the low local temperature of the alloy, and the micropore region with a lower melting point is the preferred position for incipient melting.
  • Da-shan Sui, Yu Shan, Dong-xin Wang, Jun-yi Li, Yao Xie, Yi-qun Yang, An-ping Dong, Bao-de Sun
    《中国铸造》英文版. 2023, 20(5): 403-413. https://doi.org/10.1007/s41230-023-2119-1
    摘要 ( 47 ) PDF全文 ( 39 )   可视化   收藏
    K439B nickel-based superalloy is a new type of high-temperature material. There is insufficient research on its constitutive equations and numerical modeling of thermal stress. Isothermal tensile experiments of K439B superalloy at different temperatures (20 ℃-1,000 ℃) and strain rates (1.33×10-3 s-1-5.33×10-3 s-1) were performed by using a Gleeble-3800 simulator. The elastic moduli at different temperatures (20 ℃-650 ℃) were measured by resonance method. Subsequently, stress-strain curves were measured for K439B superalloy under different conditions. The elastic-viscoplastic constitutive equations were established and the correspongding parameters were solved by employing the Perzyna model. The verification results indicate that the calculated values of the constitutive equations are in good agreement with the experimental values. On this basis, the influence of process parameters on thermal stress was investigated by numerical simulation and orthogonal experimental design. The results of orthogonal experimental design reveal that the cooling mode of casting has a significant influence on the thermal stress, while pouring temperature and preheating temperature of shell mold have minimal impact. The distribution of physical fields under optimal process parameters, determined based on the orthogonal experimental design results, was simulated. The simulation results determine separately the specific positions with maximum values for effective stress, plastic strain, and displacement within the casting. The maximum stress is about 1,000.0 MPa, the plastic strain is about 0.135, and the displacement is about 1.47 mm. Moreover, the distribution states of thermal stress, strain, and displacement are closely related to the distribution of the temperature gradient and cooling rate in the casting. The research would provide a theoretical reference for exploring the stress-strain behavior and numerical modeling of the effective stress of the alloy during the casting process.
  • Research & Development
  • Tian-yu Liu, Yan-chun Lou, Shuang Zhang, Zhi-hao Zhu, Jun Zhao, Shi-bing Liu, Kun Shi, Ning Zhao
    《中国铸造》英文版. 2023, 20(5): 414-422. https://doi.org/10.1007/s41230-023-3019-0
    摘要 ( 46 ) PDF全文 ( 48 )   可视化   收藏
    A novel Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy was designed using the cluster formula approach (cluster-plus-glue-atom model) and prepared by laser melting deposition (LMD). Its composition formula 12[Al-Ti12](AlTi2)+5[Al0.8Si0.2-Ti12Zr2](V0.8Mo0.2Nb1Ti) features an enhanced β-Ti via co-alloying of Zr, V, Mo, Nb and Si. The experimental results show that the cluster formula of α and β phases in the novel alloy are respectively α-[Al-Ti11.5Zr0.5](Al1Ti2) and β-[Al0.8Si0.2-Ti13.2Zr0.8](V1Mo0.4Nb1.6), both containing Zr elements. The fitted composition via the α and β phase cluster formulas has little difference with the actual alloy composition, suggesting that the validity of cluster-plus-glue-atom model in the alloy composition design. After hot isostatic pressing (HIP), both the Ti-6Al-4V and the novel alloy by LMD are characterized by prior-β columnar grains, while the typical <100> texture disappears. Compared with Ti-6Al-4V, Ti-5.55Al-6.70Zr-1.50V-0.70Mo-3.41Nb-0.21Si alloy exhibits a combination of higher strength (1,056 MPa) and higher ductility (14%) at room temperature and higher strength (580 MPa) at 550 ℃ after HIP, and can potentially serves as LMD materials.
  • Wei-long Wang, Kun Shi, Jun Zhao, Shi-bing Liu, Jiao-jiao Cheng, Wei-chen Qiu, Tian-yu Liu, Zhi-yong Zhang
    《中国铸造》英文版. 2023, 20(5): 423-431. https://doi.org/10.1007/s41230-023-2185-4
    摘要 ( 46 ) PDF全文 ( 26 )   可视化   收藏
    The in situ (TiC+TiB)/TA15 composites with different volume percentages of reinforcement (10%, 15%, 20% and 25%) were prepared by water-cooled copper crucible vacuum suspension melting technology. The structures and compositions of the TA15 alloy and its composites were analyzed by XRD and EDS, and their electrochemical corrosion behavior in the 3.5% NaCl solution was studied. Corrosion wear testing was conducted using a reciprocating ball-on-disc wear tester under a 10 N load. Results show that the in situ fibrous TiB phase and the granular TiC phase are uniformly distributed on the composite matrix. The microhardness can reach up to 531 HV as 10vol.% TiC+TiB reinforcement is added. Compared with the TA15 alloy, the volume wear rate decreases from (2.21±0.07)×10-4 to (1.75±0.07)×10-4 mm3·N-1·m-1 by adding 15vol.% TiC+TiB reinforcement, and the wear mechanism is adhesive wear. When the volume percentage of the reinforcement phase reaches 25%, the volume wear rate increases from (1.75±0.07)×10-4 to (2.41±0.07)·10-4 mm3·N-1·m-1, and the wear mechanism changes into abrasive wear. The volume loss resulted by the interaction between corrosion and wear accounts for more than 27% of the total wear volume. The volume loss due to wear-induced corrosion changes from 1.94% to 4.06% with different addition of reinforcement. The volume loss caused by corrosion-induced wear initially increases from 24.08% to 26.90% as the reinforcement increases from 0 to 15% due to the increase of corrosion potential, and then decreases from 26.90% to 25.68% as the reinforcement increases from 15% to 25% due to the peeling of TiC phase.
  • Chang-sheng Zhu, Tian-yu Li, Bo-rui Zhao, Cang-long Wang, Zi-hao Gao
    《中国铸造》英文版. 2023, 20(5): 432-442. https://doi.org/10.1007/s41230-023-2128-0
    摘要 ( 40 ) PDF全文 ( 32 )   可视化   收藏
    In this work, Al-4.5wt.%Cu was selected as the research object, and a phase field-lattice Boltzmann method (PF-LBM) model based on compute unified device architecture (CUDA) was established to solve the problem of low serial computing efficiency of a traditional CPU and achieve significant acceleration. This model was used to explore the evolution of dendrite growth under natural convection. Through the study of the tip velocities, it is found that the growth of the dendrite arms at the bottom is inhibited while the growth of the dendrite arms at the top is promoted by natural convection. In addition, research on the inclined dendrite under natural convection was conducted. It is observed that there is a deviation between the actual growth direction and the preferred angle of the inclined dendrite. With the increase of the preferred angle of the seed, the difference between the actual growth direction and the initial preferred angle of the inclined dendrite shows a trend of increasing at first and then decreasing. In the simulation area, the relative deflection directions of the primary dendrite arms in the top right corner and the bottom left corner of the same dendrite are almost counterclockwise, while the relative deflection directions of the other two primary dendrite arms are clockwise.
  • Ming Xu, Yan-guo Yin, Cong-min Li, Guo-tao Zhang, Cong-chong Duan
    《中国铸造》英文版. 2023, 20(5): 443-451. https://doi.org/10.1007/s41230-023-2095-5
    摘要 ( 33 ) PDF全文 ( 29 )   可视化   收藏
    The macrosegregation behaviors of Al-Sn-Cu ternary immiscible alloy castings and their effects on mechanical and tribological properties were investigated. The results demonstrate that Sn and Cu segregate in the casting simultaneously, and the mass fraction of the two elements has a “U” shaped distribution. Significantly, positive and negative segregation occur in the casting, with positive segregation appearing on the top and lower surfaces and negative segregation on the remaining surfaces, with the 1/2 surface (hot node location) having the highest degree of negative segregation. Furthermore, the results of Vickers hardness, tensile strength, and elongation show that Sn and Cu cooperatively affect the mechanical properties of castings. The higher the mass fraction of Sn and Cu elements, the higher the hardness, the greater the tensile strength, and the better the elongation. The findings of the step-by-step loading tests demonstrate that the segregation of Sn and Cu significantly impacts the tribological characteristics of the castings. The higher the mass fraction of Sn and Cu on the sample surface, the better the tribological characteristics.
  • Xiao-gang Fang, Qi Wei, Tian-yang Zhang, Ji-guang Liu, You-wen Yang, Shu-lin Lü, Shu-sen Wu, Yi-qing Chen
    《中国铸造》英文版. 2023, 20(5): 452-460. https://doi.org/10.1007/s41230-023-2146-y
    摘要 ( 42 ) PDF全文 ( 27 )   可视化   收藏
    The ultrasonic melt treatment (UMT) is widely used in the fields of casting and metallurgy. However, there are certain drawbacks associated with the conventional process of single-source ultrasonic (SSU) treatment, such as the fast attenuation of energy and limited range of effectiveness. In this study, the propagation models of SSU and four-source ultrasonic (FSU) in Al melt were respectively established, and the distribution patterns of acoustic and streaming field during the ultrasonic treatment process were investigated by numerical simulation and physical experiments. The simulated results show that the effective cavitation zone is mainly located in a small spherical region surrounding the end of ultrasonic horn during the SSU treatment process. When the FSU is applied, the effective cavitation zone is obviously expanded in the melt. It increases at first and then decreases with increasing the vibration-source spacing (Lv) from 30 mm to 100 mm. Especially, when the Lv is 80 mm, the area of effective cavitation zone reaches the largest, indicating the best effect of cavitation. Moreover, the acoustic streaming level and flow pattern in the melt also change with the increase of Lv. When the Lv is 80 mm, both the average flow rate and maximum flow rate of the melt reach the highest, and the flow structure is more stable and uniform, with the typical morphological characteristics of angular vortex, thus significantly expanding the range of acoustic streaming. The accuracy of the simulation results was verified by physical experiments of glycerol aqueous solution and tracer particles.
  • Li-dong Xing, Yan-ping Bao, Min Wang, Yi-hong Li
    《中国铸造》英文版. 2023, 20(5): 461-468. https://doi.org/10.1007/s41230-023-2155-x
    摘要 ( 47 ) PDF全文 ( 40 )   可视化   收藏
    Mold electromagnetic stirring technology for optimizing the flow of molten steel is now widely used in the continuous casting production process of high-quality steels. However, studies on the case that the center of the electromagnetic stirrer is located outside the mold have not been reported. Herein, the effect of the electromagnetic stirrer centered outside the mold on the steel flow field was studied in detail by means of numerical simulations. A Gauss meter was used to measure the magnetic induction intensity at different positions, currents, and frequencies. The test results were compared with the simulation results of electromagnetic stirring to calibrate and verify the accuracy of the electromagnetic model. Then, electromagnetic force was introduced into the flow field model as a source term to study its effect on the flow field under anomalous conditions. The results show that when the center of the electromagnetic stirrer is located outside the mold, the magnetic field strength is about twice as strong as that located inside the mold. This also leads to an increase in the flow velocity near the electromagnetic stirrer. As a result, the optimal electromagnetic stirring parameters (200 A, 2.5 Hz) were specified when the center of the electromagnetic stirrer is located outside the mold.