Tantalum − tungsten alloys are critical for extreme aerospace applications. However, the oxidation sensitivity and processability limitations associated with conventional manufacturing routes severely constrain the mechanical performance and manufacturability of tantalum−tungsten alloys. This study proposes a new process for fabricating Ta − 12W alloys using “selective laser melting + rolling + inter-pass electrical treatment” (ET − AMR), which achieves a synergistic enhancement of both strength and ductility. First, a substrate with fine grains, high density, complete element diffusion, and no segregation was fabricated using selective laser melting technology. Subsequent multi-pass rolling refined the microstructure and stored substantial deformation energy along the columnar grain growth direction. Inter-pass electrical treatment facilitated dislocation disentanglement, alleviated stress concentration, and induced strain delocalization. The combined effect of rolling and pulsed current effectively repaired internal pores and cracks, reducing the porosity from 0.15% to 0.002% and significantly improving material densification. Specific annealing procedures further enhanced the mechanical properties and grain evolution behavior of the Ta−12W alloy, with the tensile strength increasing by 63% and elongation approximately 3.3 times higher than those of the as-built state, reaching 986 MPa and 14.8%, respectively. After annealing, coarse–fine grain heterostructures and subgrain-recrystallized heterostructures formed, while columnar grains transformed into layered equiaxed grains along the build direction. During plastic deformation, the heterogeneity in grain size and type led to dislocation pile-up, further enhancing heterogeneous deformation-induced strengthening and promoting a synergistic increase in ductility under high strength. This study provides new insights into the high-performance fabrication and development of tantalum−tungsten alloys.
Herein, a magnetically separable Fe3O4/g-C3N4/BiOI (FCB) ternary composite was constructed as a visible-light-responsive photocatalyst for uranium decontamination through reduction of aqueous U(VI) to less soluble U(IV). The composite was synthesized via combined co-precipitation and hydrothermal methods. Among the prepared materials, the optimized 45
This study utilizes a hybrid methodology of molecular dynamic simulation and experimental observations to elucidate the intrinsic mechanism through which grain size influences the machined surface quality of pure metallic materials, systematically examining correlations among material removal mechanisms, deformation behavior, and microstructural evolution across varying grain size scales. The results demonstrate that grain size significantly affects machined surface integrity by modifying deformation mechanisms, with its effect strongly linked to a transition in the dominant deformation mechanism from dislocation slip to grain boundary sliding. Transmission electron microscopy characterization confirms that the machined subsurface of pure aluminum metal exhibits amorphous phases and stacking faults, hence corroborating the material deformation mechanism in nanocutting. This study elucidates the formation pathway of distinctive microstructures in nanocutting of pure metallic materials, offering a theoretical foundation for attaining high-precision machining of metallic materials through grain size modulation.
Droplet impact on superhydrophobic surfaces has attracted significant attention due to its relevance to a wide range of engineering applications, such as anti-icing, self-cleaning and hydroelectric generation. In practice, droplets rarely fall vertically without initial motion. Aerodynamic and external disturbances often impart rotation, which significantly influences their impact dynamics. However, the impact dynamics of droplets with initial angular velocity on superhydrophobic surfaces remain poorly understood. Here, we investigate the dynamics of self-rotating droplets impacting superhydrophobic surfaces through numerical simulations, covering a broad range of droplet initial angular velocities from 0 to 700 rad/s. We find that increasing the droplet initial angular velocity leads to stronger centrifugal forces and higher rotational kinetic energy, which affects the balance between inertial and capillary forces, thereby enhancing droplet spreading and significantly reducing the contact time. Further, we systematically analyze how angular velocity influences both spreading and retraction stages, revealing critical mechanisms governing droplet behavior under rotational conditions. Based on these mechanisms, scaling laws are derived to accurately predict the maximum spreading coefficient and the contact time, demonstrating excellent agreement with the simulation results. These findings enhance the understanding of self-rotating droplet dynamics on superhydrophobic surfaces and provide guidance for related practical applications.
A semi-analytical method is proposed to solve the dynamic response of a laminated composite sandwich beam incorporating various lattice truss cores. Under the premise of satisfying Allen's classical sandwich beam assumption, the displacement expressions of the three parts of the sandwich beam are established separately by combining Bernoulli–Euler beam and Timoshenko beam theories. The Legendre polynomial is utilized to construct the displacement tolerance function of the structure. To accommodate various engineering requirements in practical applications, displacement and torsion springs are placed at both ends of the beam in this study. By adjusting the stiffness of the two springs and their combination, arbitrary boundary conditions can be effectively simulated. The Lagrange energy method is employed to construct a unified vibration equation for the entire structure. Finally, the variational solution is obtained by the Rayleigh–Ritz method. After the computational comparison and analysis, the validity of the method proposed in this paper is verified with a fast convergence speed and high degree of accuracy. Based on this, in-depth investigations on the steady-state and transient responses of displacement deflection in laminated composite sandwich beams with various lattice truss cores are further conducted. The findings offer valuable insights for studying the dynamic characteristics of sandwich beam structures incorporating lattice truss cores, thereby providing practical guidance in this field.
