A Comprehensive Review of Bridgman Solidification of High-Entropy Alloys

Conventional casting of high-entropy alloys was constrained by multi-principal element solidification behavior and was prone to severe grain boundary segregation and microstructural inhomogeneity, limiting their service performance in extreme environments. Bridgman directional solidification can help to achieve oriented columnar grain growth and mitigate micro-segregation via tailored matching of a temperature gradient, G, and a growth rate, V, yet its stable solidification relied on a high G/V ratio, imposing stringent requirements on equipment and process control. Trace rare earth elements are suggested to potentially stabilize the interfacial morphology and effectively broaden the processing window of Bridgman directional solidification through melt purification and modulation of the solid–liquid interfacial energy based on extrapolation from conventional casting and thermodynamic principles; however, direct experimental confirmation in Bridgman-processed HEAs remains scarce. This review summarizes the solidification microstructure evolution of high-entropy alloys fabricated by the Bridgman method, elucidates the regulatory mechanisms of rare earth microalloying on phase selection, solute partitioning behavior, and interface stability, and reveals the strengthening effects and corrosion performance variations under the synergistic interaction of processing parameters and chemical compositions. Finally, future perspectives are provided regarding interfacial reactions, compositional homogeneity control, and the lack of design criteria in Bridgman-based rare earth composite fabrication systems.