In this article, design, fabrication, and testing of SiC/SiC turbine blisk with the fiber’s preform of Spider Web Structure (SWS) subjected to different load spectrums at elevated temperature are conducted. Micro-CT scans are conducted to show the fibers preform and defects inside the SWS-SiC/SiC turbine blisk. For 2D plain-woven SiC/SiC composite under monotonic tensile loading at an elevated temperature of T = 900°C in air atmosphere, the composite ultimate tensile strength is σ _uts = 200 MPa with the fracture strain ε _f = 0.36%. For SWS-SiC/SiC turbine blisk under the rotation testing, the first and second order natural frequency of the SWS-SiC/SiC turbine blisk are tested using the laser vibration meter. Relationships between the rotation speed, internal damage, and the natural frequency degradation of the SWS-SiC/SiC turbine blisk are established. Under the maximum rotation speed of n = 17,000 rpm at the exhaust temperature of T = 930°C, no damage occurred in the SWS-SiC/SiC turbine blisk. However, multiple coating spalling occurred due to the thermal-chemical coupling failure of the coating under flame impingement. The first natural frequency of the SWS-SiC/SiC turbine blisk decreases by 5% with the increase in the rotating speed from n _max = 85,000 rpm to n _max = 105,000 rpm, which indicates that there is an internal damage in the SWS-SiC/SiC turbine blisk, which leads to the decrease in the stiffness of the blisk.

In order to verify the feasibility of three-dimensional (3D) printing technology in preparing the metamaterial absorbers with complex structure, a three-layer broadband absorbing metamaterial is designed and fabricated by 3D printing technology. The surface layer and middle layer of the metamaterial are composed of periodic arrays with different unit dimensions and the bottom layer of a slab structure. The optimized thickness of the metamaterial is 4.7 mm. A composite absorbent which consists of carbonyl iron powder and nylon is used to fabricate the absorber. In experiment, the obtained absorber is vertically irradiated by an electromagnetic (EM) wave. Two strong absorption peaks at 5.3 GHz and 14.1 GHz are achieved, with the reflection losses of -15.1 dB and -12.5 dB, respectively. The superposition of the two absorption peaks results in a reflection loss below -10 dB in a range from 4 to 18 GHz. The effective EM parameters of the surface layer and the middle layer are calculated by the S parameter inversion method. An effective model of the three-layer structure absorber is proposed and its reflectivity is calculated by using a multilayer structure reflectivity formula. The calculated reflectivity agrees well with the measured one. The absorbing and resonance mechanisms of the two absorption peaks are investigated by analyzing the dynamic distributions of power density loss, electric field and magnetic field. It can be clearly confirmed that the reflection losses at 5.3 GHz and 14.1 GHz are primarily concentrated on the bottom layer and surface layer, and the broadband absorption performance can be derived from the superposition of broadband absorptions of the three absorbing layers. Meanwhile, the strong electric coupling effect between the adjacent units in the surface layer is demonstrated by analyzing the electric-field distributions, which indicates that the strong reflection loss at 14.1 GHz is mainly caused by the electric response. The multiple scattering effects among the three layers are also considered according to the magnetic field distributions at two resonance frequencies. It is shown that there are two magnetic responses at 5.3 GHz and 14.1 GHz, respectively, and the multiple scattering contributes to increasing the EM wave propagation distance and enhancing the power loss. The designed absorbing metamaterials in this paper achieve good broadband absorption performances, particularly in the low frequency band. Combined with 3D printing rapid technology, a promising route to constructing 3D absorbing metamaterials with complex structures is proposed, which would be of great significance and broad practical prospect.

Eight diffusion couples were fabricated to systematically investigate the composition-dependent interdiffusion behavior in hcp Dy-Y, Dy-Nd, Sm-Nd, and Sm-Tb binary alloys. The interdiffusion coefficients were determined at two representative temperatures using the Sauer–Freise method based on concentration–distance profiles measured by electron probe microanalysis (EPMA). These experimentally obtained diffusivities, together with available thermodynamic data, were subsequently employed to assess the atomic mobilities of each system by means of the CALTPP (CALculation of Thermo Physical Properties) program within the CALPHAD (CALculation of PHAse Diagrams) framework. The optimized mobility parameters provide a reliable description of the diffusion behavior in all investigated alloys. This reliability is confirmed by the close agreement between the calculated and experimentally measured interdiffusion coefficients, as well as by the strong consistency between the model-predicted and experimental concentration profiles. The present work thus establishes the first set of critically evaluated atomic mobility parameters for these hcp rare-earth binary systems. These results fill an important gap in the kinetic database of rare-earth alloys and lay a robust foundation for future multi-component CALPHAD-based simulations, thereby supporting the design and optimization of advanced rare-earth permanent magnets with improved coercivity and thermal stability.

The phase equilibria of the Si-C-Cu ternary system at 700 °C and 810 °C were experimentally investigated for the first time. Fifteen key alloys were prepared via powder metallurgy and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Isothermal sections were constructed based on the identified equilibrium phases. At 700 °C, eight single-phase regions and six three-phase regions—(C)+(Cu)+hcp, (C)+hcp+γ-Cu₃₃Si₇, (C)+γ-Cu₃₃Si₇+SiC, γ-Cu₃₃Si₇+SiC+ε-Cu₁₅Si₄, SiC+ε-Cu₁₅Si₄+η-Cu₃Si(ht), and SiC+(Si)+η-Cu₃Si(ht)—were determined. At 810 °C, nine single-phase regions and seven three-phase regions were identified. The solubility of C and Si/Cu in the various phases was quantified and found to be significantly higher at 810 °C compared to 700 °C. Key differences include the presence of the bcc (β) and liquid phases at 810 °C. The results demonstrate that higher temperatures promote increased mutual solubility and reaction tendencies among Cu, C, and Si. Motivated by these findings, the influence of vacuum hot pressing parameters on SiC-fiber-reinforced Cu composites (SiC_f/Cu) was investigated. The optimal processing condition (1050 °C, 60 MPa, 90 min) yielded a high bending strength of 998.61 MPa, attributed to enhanced diffusion and interfacial bonding facilitated by the high-temperature phase equilibria. This work provides essential fundamental data for understanding interactions and guiding processing in SiC-reinforced Cu composites.