Effect of Silicon Addition on the Phase Symmetry and Microstructural Stability of High-Entropy Alloys During Heat Treatment

This study investigates the role of silicon (Si) addition in governing the evolution of phase symmetry and microstructural stability in a high-entropy alloy (HEA) synthesized via powder metallurgy. Mechanically alloyed powders were consolidated through conventional sintering, followed by systematic heat treatment to examine symmetry-driven phase transformations. Particular attention is given to the symmetry relationship between body-centered cubic (BCC) and face-centered cubic (FCC) crystal structures and their compositional stabilization mechanisms. X-ray diffraction and microstructural analyses reveal that Si incorporation modifies lattice symmetry, promotes controlled phase transformation, and influences the balance between competing crystallographic phases. The addition of Si contributes to symmetry stabilization by reducing heterogeneity in lattice distortion and suppressing grain coarsening during thermal exposure. These findings demonstrate that compositional tuning can regulate structural symmetry and phase equilibrium in multicomponent alloy systems. The work provides insight into symmetry-controlled material design strategies for enhancing the thermal robustness and structural reliability of HEAs for high-temperature applications.