This paper proposes a new supporting method that utilizes a directionally controllable high-pressure air jet to provide adaptive support for thin floor milling. Unlike conventional rigid moving supports that provide only positive contact pressure, the proposed method can switch between positive pressure and suction pressure by controlling the flow direction of the air jet. The core innovation lies in the adaptive switching between bidirectional forces: when milling at a low axial depth of cut, the air jet flows toward the floor to generate positive pressure that suppresses vibro-impact vibration; when milling at a high axial depth of cut, the air jet flows away from the floor to generate suction pressure that counteracts the axial milling force and suppresses overcut. This bidirectional force capability, combined with the non-contact nature of the air jet support, distinguishes the proposed method from existing mobile support devices. An experimental platform is constructed to verify the feasibility. The results indicate that the high-pressure air jet with controllable flow direction is effective to suppress both vibro-impact vibration and overcut, and successfully avoids backside surface damage. The average roughness decreases by up to 17% and the maximum thickness error decreases by up to 65% with air jet assistance. The developed method expands the applicability of current milling processes and provides valuable insights for the design of air jet support systems.
Due to their excellent physical properties, InAs/InxGa1-xAsySb1-y type-II superlattices (SLs) have become promising materials for the active regions of infrared devices. Their translation into practical applications, especially in harsh environments such as space, requires detailed knowledge of their structural and optoelectronic stability under extreme conditions. The response of these quaternary SLs to high-energy electron irradiation, however, has not been extensively investigated. In this work, the structural and luminescence properties of InAs/In0.5Ga0.5As0.5Sb0.5 SLs exposed to 1.25 MeV electron irradiation at absorbed doses of 0, 5, 50, and 100 kGy are investigated. High-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM)/energy-dispersive X-ray spectroscopy (EDS) measurements show irradiation-induced peak broadening, increased lattice mismatch, surface roughening, interface blurring, As/Sb interdiffusion, and progressive In redistribution, while the overall superlattice periodic stacking remains observable. Geometric phase analysis (GPA) further reveals dose-dependent modification of the local strain distribution. Power-dependent photoluminescence (PL) measurements indicate a dose-dependent shift from predominantly free-exciton-like radiative recombination toward an increasing contribution from defect-assisted non-radiative recombination. These results establish a correlation between irradiation dose, interfacial and compositional disorder, carrier localization, and optical degradation in the quaternary type-II superlattice.
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.
The tool influence function (TIF) modelling for magnetorheological finishing (MRF) is crucial for ultra-precision fabrication of aspheric cylindrical components, and has been widely studied. Nonetheless, the existing TIF modelling methods for MRF suffer from several shortcoming when applied in industry, including the need for physicochemical measurements, the unanalytical hydrodynamics, and the inaccurate calibration of influence coefficient, unresolved coupling between physicochemical and geometric factors, and inapplicability to complex surfaces. To overcome those deficiencies, this work proposes an exponential-trigonometric-spline (ETS) based TIF modelling method for MRF of aspheric cylinder incorporating full decoupling, analytical hydrodynamics, and nonlinear calibration. First, the influences of physicochemical and geometric factors on the TIF for cylindrical surface are decoupled. An ETS-based model for pressure and shear stress is established, and the TIF is reconstructed through nonlinear calibration of the influence coefficient. Then the roles of morphological coefficients in the TIF formation mechanism for MRF are elucidated, and the evolution law of those coefficients with respect to curvature and immersion depth is modelled using a stepwise bivariate Hermite interpolation (SBHI) algorithm. Finally, an efficient deduction method based on an iterative contact-adaptive matching (ICAM) algorithm is proposed. Compared with existing methods, the proposed approach exempts physicochemical measurements, fully decouples physicochemical and geometric factors, and significantly improves adaptability to the contact area on aspheric cylinder. Simulation and experimental results demonstrate that the proposed method significantly improves the accuracy and reliability of TIF reconstruction and deduction compared with conventional methods. For TIF reconstruction, APRRE, AVRRE, and ACE are reduced by 69.63∼96.59%, 30.33∼67.75%, and 25.55∼50.67%, respectively. For TIF deduction, corresponding reductions of 10.74∼84.16%, 8.59∼51.24%, and 12.63∼55.29% are achieved. This work provides important technical support for improving the precision and determinism of MRF for complex surface.
