Current Issue : April-June Volume : 2025 Issue Number : 2 Articles : 5 Articles
Spark plasma sintering (SPS) is an effective technique for studying the diffusion bonding of diamond/Cu composites, and has the potential to advance the application of copper matrix composites. This study investigates the SPS diffusion bonding of diamond/Cu composites using a chromium (Cr) interlayer. The effects of process parameters on the microstructure and mechanical properties of the bonding interface were evaluated through shear strength testing and SEM analysis. The results show that shear strength increases with interlayer thickness up to a certain point, after which it decreases. As the bonding temperature, holding time, and bonding pressure increase, defects such as cracks and voids at the diffusion-bonded interface are reduced, resulting in improved shear strength. Under suitable conditions (10 μm interlayer, 810 ◦C, 60 min, and 10 MPa), the bonding interface is defect-free, achieving a maximum shear strength of 139.89 MPa and a thermal conductivity (TC) of 700.97 W/(m·K), indicating high-quality diffusion bonding....
Metal Binder Jetting (BJT/M) has emerged as a promising additive manufacturing (AM) technology for the realization of complex parts using a wide range of metal alloys. This technology offers several advantages, such as design flexibility, reduced lead times, a high building rate, and the ability to fabricate intricate geometries that are difficult or impossible to achieve with conventional manufacturing methods. Cobalt Chromium Molybdenum (CoCrMo) alloys are particularly suitable for demanding applications in the aerospace, biomedical, and industrial sectors that require high strength and hardness, corrosion resistance, and biocompatibility. In this work, ten cubic and ten tensile samples were printed with a layer height of 50 μm using the shell printing method, debound and sintered at 1325 ◦C for 4 h, with the aim of investigating the properties of CoCrMo parts made using BJT technology. A density of 7.88 g/cc was obtained from the Archimede’s test. According to the printing and sintering parameters, an average hardness of 18.5 ± 1.8 HRC and an ultimate tensile strength of 520.5 ± 44.6 MPa were obtained. Finally, through a microstructure analysis, an average grain size of 182 ± 14.7 μm was measured and the presence of an intergranular Cr-rich phase and Mo-rich carbides was detected....
This paper proposed a novel real-time inductance tracking algorithm. This algorithm estimates the inductance of interior permanent magnet synchronous motors (IPMSMs) using electrical and mechanical equations. Unlike the conventional algorithms, the proposed online inductance identification algorithm does not need information on magnetic flux. Therefore, the parameter can be estimated of the variation with the operating point and cross-saturation effect. In this paper, a novel real-time parameter tracking algorithm based on the electrical torque estimator is derived. The feasibility and usefulness of the proposed inductance estimation technique are verified by simulation and experimental results....
Truss-braced wings (TBWs) feature higher aspect ratios with a lighter weight and lower bending moment than conventional wings. These wings show significant potential for performance improvements in terms of fuel efficiency. However, additional configurations of these wings also present nonlinear problems and challenges in aeroelastic designs. This paper investigates the static response of a TBW with a high aspect ratio, specifically focusing on the impact of the spanwise joint location on aeroelastic characteristics. The TBW is modeled by nonlinear beam elements and the unsteady vortex-lattice method (UVLM). The results show that the bending deformation is effectively reduced by the truss member and the deformation is impacted by the location of the spanwise joint connected to the main body....
Despite the extensive use of 7xxx aluminum alloys in aerospace, intergranular corrosion is yet to be appropriately addressed. In this work, in situ rolling friction stir welding (IRFSW) was proposed to improve the corrosion resistance of joints via microstructural design. A gradientstructured layer was successfully constructed on the surface of the joint, and the corrosion resistance was improved by in situ rolling. The intergranular corrosion depth of the IRFSW joint was reduced by 59.8% compared with conventional joints. The improved corrosion resistance was attributed to the redissolved precipitates, the disappearance of precipitate-free zones, and the discontinuous distribution of grain boundary precipitates. This study offers new insights for enhancing the corrosion resistance of aluminum alloy FSW joints....
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