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Cr concentration driving the structural, mechanical, and thermodynamic properties of Cr‐Al compounds from first‐principles calculations
Author(s) -
Pan Yong
Publication year - 2019
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25943
Subject(s) - tetragonal crystal system , debye model , monoclinic crystal system , crystallography , bulk modulus , materials science , thermodynamics , density functional theory , chemistry , bond length , crystal structure , computational chemistry , physics , composite material
Cr‐Al binary compounds are regarded as the potential high‐temperature structural materials. However, the structure and important properties of Cr‐Al compounds are not completely unclear. Here, we report on the influence of Cr concentration on the structural, mechanical, and thermodynamic properties of Cr‐Al compounds by using the first‐principles calculations. Four novel Cr‐Al compounds, Cr 3 Al 8 with monoclinic structure ( C2/m ), Cr 3 Al 5 with hexagonal structure ( P63mc ), Cr 2 Al 3 with tetragonal structure ( I4/mmm ), and Cr 3 Al with cubic structure ( Pm‐3 m ), are predicted. The calculated elastic modulus of Cr‐Al compounds gradually increases with increasing Cr concentration. Compared to other Cr‐Al compounds, our predicted Cr 3 Al with cubic structure exhibits a strong deformation resistance and high hardness due to symmetrical CrAl bonds. However, the Debye temperature of Cr 7 Al 3 is larger than that of other Cr‐Al compounds. The calculated phonon density of state shows that the high‐temperature thermodynamic properties of Cr‐Al compounds are attributed to the vibration of Al atom and CrAl bond.