TY - JOUR
T1 - Phonon and thermodynamic properties of Al-Mn compounds
T2 - A first-principles study
AU - Shang, S. L.
AU - Wang, J.
AU - Wang, Y.
AU - Du, Y.
AU - Liu, Z. K.
N1 - Funding Information:
This work was funded by the US Office of Naval Research under Contract No. N0014-07-1-0638, the U.S. National Science Foundation through Grant No. DMR-1006557 , and the National Science Foundation of China under Grant Nos. 50721003 , 50831007 and 51028101 . First-principles calculations were carried out partially on the LION clusters supported by the Materials Simulation Center and the Research Computing and Cyber infrastructure unit at Pennsylvania State University, and partially on the resources of NERSC supported by the Office of Science of the US DOE under Contract No. DE-AC02-05CH11231. YD and ZKL also acknowledge the Cheung Kong Professorship released by the Minister of Education of China for financial support.
PY - 2011/5
Y1 - 2011/5
N2 - Based on first-principles calculations within the projector augmented wave method and the generalized gradient approximation, the structural, thermodynamic as well as phonon properties of Al-Mn compounds have been investigated. The compounds studied include Al12Mn, Al6Mn, Al 8Mn5, Al10Mn3, Al 11Mn4 (low temperature phase), γ-AlMn, ε-AlMn, and τ-AlMn. Besides phonon calculations, Debye model is also used to evaluate the thermodynamic properties at elevated temperatures, which are compared with available data from experiments and thermodynamic modeling. A good agreement is found between first-principles calculations and experimental values or CALPHAD-type calculations. For Al-Mn compounds with lower Mn content, it is observed that (i) the equilibrium volume decreases roughly linearly while the bulk modulus increases roughly linearly with increasing Mn content, (ii) the bonding strength follows the trend of Al-Al > Al-Mn (and Mn-Mn) at a fixed bond length, and (iii) roughly the higher the Mn content of Al-Mn compounds, the smaller the vibrational contribution to entropy, and in turn, to Gibbs energy. The demonstrated methodology herein, as well as the predicted thermodynamic properties, provides helpful insights into the stability of phases and thermodynamic modeling, especially for system where the experimental information is lacking or less reliable.
AB - Based on first-principles calculations within the projector augmented wave method and the generalized gradient approximation, the structural, thermodynamic as well as phonon properties of Al-Mn compounds have been investigated. The compounds studied include Al12Mn, Al6Mn, Al 8Mn5, Al10Mn3, Al 11Mn4 (low temperature phase), γ-AlMn, ε-AlMn, and τ-AlMn. Besides phonon calculations, Debye model is also used to evaluate the thermodynamic properties at elevated temperatures, which are compared with available data from experiments and thermodynamic modeling. A good agreement is found between first-principles calculations and experimental values or CALPHAD-type calculations. For Al-Mn compounds with lower Mn content, it is observed that (i) the equilibrium volume decreases roughly linearly while the bulk modulus increases roughly linearly with increasing Mn content, (ii) the bonding strength follows the trend of Al-Al > Al-Mn (and Mn-Mn) at a fixed bond length, and (iii) roughly the higher the Mn content of Al-Mn compounds, the smaller the vibrational contribution to entropy, and in turn, to Gibbs energy. The demonstrated methodology herein, as well as the predicted thermodynamic properties, provides helpful insights into the stability of phases and thermodynamic modeling, especially for system where the experimental information is lacking or less reliable.
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U2 - 10.1016/j.commatsci.2011.02.015
DO - 10.1016/j.commatsci.2011.02.015
M3 - Article
AN - SCOPUS:79954417922
VL - 50
SP - 2096
EP - 2103
JO - Computational Materials Science
JF - Computational Materials Science
SN - 0927-0256
IS - 7
ER -