Open Access
Review
13 June 2025Advances in Sintering Technologies for SiC Ceramics: Mechanisms, Challenges, and Industrial Applications
Silicon carbide (SiC) ceramics have become critical materials for high-temperature engineering applications because of their exceptional mechanical strength, thermal conductivity, and chemical stability. In order to meet the diverse needs of industrial applications, various sintering methods have been developed. These include traditional methods such as pressureless sintering, reaction-bonded sintering, hot pressing, and recrystallization, as well as advanced technologies like spark plasma sintering, oscillatory pressure sintering, and flash sintering. This review provides a systematic analysis of both traditional and advanced sintering techniques for SiC ceramics. It highlights their mechanisms, critical process parameters, and impacts on the final material properties. Key challenges, including high sintering temperatures, additive selection, microstructural control, and scalability, are examined. Strategies for balancing cost-efficiency with performance are also discussed. In addition, recent advancements in SiC-based composite materials for applications ranging from aerospace components to catalytic filtration systems are presented. Finally, future research directions are proposed. These focus on precise additive engineering, microstructure tailoring, and innovative sintering methodologies to speed up the transition of high-performance SiC ceramics from laboratory prototypes to large-scale industrial implementation.
Open Access
Review
19 June 2025Research Progress on High-Entropy Fibrous Materials
Due to their lightweight, high strength, and thermal resistance, HEFMs exhibited significant potential in aerospace, energy storage, environmental protection, and defense. This review systematically presented the research progress on high-entropy fibrous materials (HEFMs), covering their fundamental concepts, fabrication methods, crystal structure characteristics, performance advantages, and application fields. The different crystal structure types and fabrication techniques of high-entropy ceramic fibers and high-entropy alloy fibers were discussed. Additionally, the mechanical property advantages of HEFMs and their applications in thermal insulation materials, catalysis, and energy storage were analyzed. Finally, the current challenges in HEFM research and provide an outlook on future development directions.
Open Access
Article
20 June 2025Optimization of Powder Distribution and Feeding Efficiency Using an Annular Powder-Feeding Nozzle: A Numerical and Experimental Study
The quality of spherical powders required in plasma spheroidization is particularly important to advanced manufacturing, such as additive manufacturing and thermal spray coatings. Traditional powder feeding systems, such as radial and coaxial nozzles, often suffer from suboptimal powder distribution, low powder capture efficiency, and poor control of particle trajectories. These issues deteriorate spheroidization quality and material efficiency. We propose here an innovative annular powder-feeding plasma torch for these challenges and to optimize the powder-feeding dynamics. The novel nozzle consists of a tangential powder feeding mechanism and a concentric conical structure that provides uniform powder distribution and minimizes plasma jet interference. Computational fluid dynamics (CFD) simulations and Discrete Phase Modeling (DPM), combined with a literature review, are used to study such as throat size and convergent-divergent profiles of nozzles for gas-powder interactions. Yttria-Stabilized Zirconia (YSZ) powder was used for the experimental validation of the annular nozzle; the annular nozzle was found to outperform traditional nozzles in this application with a powder capture efficiency of 75%, a deposition efficiency of 92%, and a spheroidization efficiency of 85%; 85% of the particles had a circularity index >0.9. These results indicate that powder distribution uniformity, deposition efficiency, as well as spheroidization quality are greatly improved than those from conventional plasma spheroidization systems, demonstrating the potential for better process performance for plasma spheroidization. These findings demonstrate the relevance of the optimized annular nozzle in the field of high-value material manufacturing as it yields increased coating quality and minimized material wastage.
Open Access
Article
01 July 2025Experimental and Numerical Study of Formation Mechanism of Dual-Phase (AlCoCrFeNi)X HEAs Brazed Joints by Reactive Ni/Al Nano-Multilayers
The FCC + BCC dual-phase solid solution structure was obtained in the Al0.1CoCrFeNi/304SS brazed joints using Ni/Al reactive multilayer nano-foils, which was proved by combining experiments with simulation. In this study, Finite Element Analysis was achieved to analyze the diffusion behavior across brazing joints, which were subsequently interrelated with the formation mechanism of the brazed micro-structures during the brazing process. During brazing, the joint interface is tightly bonded, and the atoms are diffused sufficiently to form the solid solution zone. The representative microstructure of the joint mainly comprised hard BCC (Al-Ni) + ductile FCC (Co-Fe-Cr) dual-phase. The successful use of nano-multilayer foils as a HEAs filler design can broaden the application range of HEAs and provide a novel procedure for brazing 304SS and Al0.1CoCrFeNi HEAs, and developing a novel field in the manufacture of HEAs-related joints.
Open Access
Review
28 July 2025Laser-Assisted Forming of Ultra-High Strength Steels: A Critical Review of Mechanisms, Processes, and Future Directions
Ultra-high strength steels (UHSS) are critical for lightweighting in the automotive and aerospace industries, but their poor room-temperature formability presents a significant manufacturing barrier. Laser-assisted forming (LAF) has emerged as a key enabling technology that utilizes localized laser heating to reduce forming forces, enhance ductility, and mitigate springback. This paper provides a critical review of the state-of-the-art in LAF of UHSS. It begins by elucidating the governing principles, including the coupled thermo-mechanical and metallurgical mechanisms such as thermal softening, dynamic microstructure evolution, and non-equilibrium phase transformations. The review then systematically surveys the major LAF process variants—including bending, roll forming, and incremental forming—and their applications in fabricating complex UHSS components. Despite its proven advantages, significant challenges impede its widespread industrial adoption. The most critical issues are identified and discussed, including local mechanical property degradation due to uncontrolled thermal cycles, the complexity of predictive multi-physics modeling, and the need for robust in-situ process monitoring and control. Ultimately, this review presents a forward-looking perspective, proposing future research directions that focus on microstructure management, the development of high-fidelity digital twins, and the implementation of intelligent closed-loop control systems to ensure process stability and part integrity. This work provides a comprehensive roadmap for advancing the science and technology of LAF for next-generation lightweight manufacturing.
Open Access
Article
31 July 2025Experimental Study on the Strength Distribution and Pore Distribution of Industrial Pellet and DRI
Against the backdrop of the “dual-carbon” goals driving the steel industry's transition toward hydrogen metallurgy, the hydrogen-based shaft furnace process has emerged as a focal point due to its low-carbon emissions. This study employs compression testing, mercury intrusion porosimeter, and industrial computed tomography characterization to compare the mechanical properties and pore structures of industrial pellets and direct reduced iron (DRI). The results show that the compressive strength and mass specific breakage energy of DRI are lower than those of pellets, and the breakage characteristic parameters at the same particle size are lower, making it more prone to breakage; the compressive strength of both increases with the increase of particle size, the mass specific breakage energy decreases with the increase of particle size, and the strength growth rate of pellets is faster. In terms of pore structure, pellets are mainly composed of uniform macropores of 3428 nm with a porosity of 22.3%; DRI has a porosity of 48.8%, mainly composed of 3431 nm macropores and 831 nm micropores, with a low tortuosity index, which is conducive to gas diffusion. This study provides parameters and theoretical basis for modeling of burden movement and crushing in shaft furnace.
