Order-Disorder Phase Transition in Silicon-containing High-Entropy Materials

High-entropy alloys (HEAs), as a significant branch of multi-principal element alloys, have garnered extensive attention due to their exceptional mechanical and functional properties. This review focuses on the order-disorder phase transition mechanisms in silicon-based HEAs, systematically addressing the thermodynamic and kinetic regulation principles and their impact on material performance. Studies have demonstrated that the incorporation of silicon optimizes atomic size matching and mixing enthalpy, enabling the coordinated coexistence of ordered and disordered phases in high-entropy alloys, thereby significantly enhancing their mechanical and physicochemical properties. The evolution of ordered and disordered phases is critically governed by fabrication processes. Advanced fabrication techniques, such as laser cladding and powder metallurgy, alongside temperature/pressure modulation, enable precise control over phase formation and hierarchical structures, achieving synergistic strengthening through multiphase architectures.Rapid cooling techniques like laser cladding suppress nucleation and growth of brittle intermetallic compounds, favoring single-phase FCC structures. Conversely, controlled annealing treatments can induce phase transitions towards ordered BCC/B2 structures, enhancing high-temperature stability. Advanced techniques such as powder plasma arc additive manufacturing (PPA-AM) leverage rapid solidification to refine grain size and disperse second phases effectively. Thermodynamic drivers, particularly the competition between entropy and enthalpy quantified by the parameter Ω, alongside external stimuli like pressure, provide precise control over phase transformation pathways and final microstructures. Furthermore, silicon incorporation enhances functional properties, including elevated electrical resistivity, tailored magnetic responses, and improved high-temperature oxidation resistance through Al₂O₃/SiO₂ layer formation. Despite these advancements, challenges remain in understanding atomic-scale dynamics of phase transitions and scaling up cost-effective manufacturing processes. Future efforts should integrate multiscale characterization, computational modeling, and performance validation under extreme conditions to accelerate the engineering applications of silicon-based HEAs in aerospace, energy storage, and electronic devices.