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Journal of Synthetic Crystals ›› 2026, Vol. 55 ›› Issue (6): 949-955.DOI: 10.16553/j.cnki.issn1000-985x.2026.0036

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Formation Mechanism of Vacancies on M2SnC (M=Ti, V, Hf, Zr) and Its Effect on Mechanical Properties

SHEN Yunan1(), PING Yutong1, HUANG Miaoyan1, CHEN Yue1, LIU Yushuang1,2()   

  1. 1.Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology,School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing 211167,China
    2.Jiangsu Key Laboratory of Advanced Metallic Materials,School of Materials Science and Engineering,Southeast University,Nanjing 211189,China
  • Received:2026-03-09 Online:2026-06-20 Published:2026-07-07
  • Contact: LIU Yushuang

Abstract: To address the unresolved issues regarding the formation of Sn vacancies in M2SnC (M=Ti,V,Hf,Zr) and its influence on mechanical properties,this study systematically employed the first-principles calculation method based on density functional theory to investigate the formation energies,structural stability of Sn vacancies,and their effects on mechanical properties. The results indicate that the formation energies of Sn vacancies in M2SnC are lower than those of M and C vacancies,suggesting that Sn vacancies are more readily formed. Among the compounds,V2SnC exhibits the lowest formation energy for Sn vacancies,while Zr2SnC shows the highest formation energy for Sn vacancies. The formation enthalpy calculation and elastic constant analysis reveal that the structures remain thermodynamic and mechanical stablility after the introduction of Sn vacancies. Mechanical property analysis demonstrates that the influence of Sn vacancies varies significantly across different M2SnC phases. After the introduction of Sn vacancies,the bulk modulus,shear modulus and elastic modulus of Ti2SnC,Hf2SnC and Zr2SnC decrease,whereas the shear modulus and elastic modulus of V2SnC increase,whose enhancement may be attributed to vacancy-induced local bond reconstruction. MAX phases are a family of ternary layered carbide/nitride ceramic materials.The research results provide a theoretical foundation for the construction and modulation of A-site vacancies in MAX phases.

Key words: M2SnC; Sn vacancy; first-principle; formation energy; mechanical property

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