180° domain related to structurally complex crystals in Al60Cr20Fe10Si10

Highlights: • We found a novel 180° domain caused by inversed structural blocks. • Atomically resolved structures of the 180° domain are revealed. • Projected structural models of the domain boundaries are proposed. • Formation mechanisms of the 180° domain are discussed. -- Abstract: In conventional crystals, the 180° domain is generally reflected by the inversed arrangement of the orientation of unit cells in nearby domains. Herein, we report a special 180° domain related to the inverse arrangement of structural blocks in structurally complex phases in an Al₆₀Cr₂₀Fe₁₀Si₁₀ alloy. The structural features were investigated in detail by high-angle annular dark-field scanning transmission electron microscopy with atomic resolution. Furthermore, the corresponding projected structural models of the domain boundaries were proposed. Finally, the structure and the formation mechanism of the 180° domain are compared and discussed with an antiphase domain in the same alloy system.