Calculation of Thermodynamic Properties for B2-YCu Intermetallics with Molecular Dynamics

Abstract:

The thermodynamic properties of YCu intermetallics with B2 structure are investigated with molecular dynamics. The thermodynamic properties at various temperatures, such as lattice parameter, cohesive energy, enthalpy of formation, elastic constants, heat capacity, vibrational entropy and vibrational free energy are computed. The present calculated results show good agreements with available experimental and previous calculated data. The calculated elastic constants suggested that YCu compound has a mostly ductile behavior. This prediction match well with experimental findings. At high temperature, the heat capacity tends to a constant with obeys the classical equipartition law. At 300K, the heat capacity of YCu is 23.80J mol-1 K-1. The calculated coefficient of thermal volume expansion α increases sharply at T<20K. When T<300K α gradually approaches a linear increase with enhanced temperature and the propensity of increment becomes moderate. At T=300K, the value of α is 5.88×10-5K-1. And those data enrich thermodynamic data-base for YCu compound.

• Periodical: Advanced Materials Research (Volumes 581-582)
• Pages: 798-802
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.581-582.798
• Online since: October 2012
• Authors: Long Shan Xu, Yu Rong Wu
• Keywords: Molecular Dynamic (MD), Thermodynamic, YCu Intermetallics

References

[1] P. Lazar, R. Podloucky, Ab initio study of the mechanical properties of NiAl microalloyed By X=Cr, Mo, Ti, Ga, Phys. Rev. B. 73(2006)104114.

[2] P. Gumbsch,R. Schroll, Atomistic aspects of the deformation of NiAl, Intermetallics. 7(1999)447-454.

DOI: 10.1016/s0966-9795(98)00096-x

[3] K. A. GschneidnerJr., A. M. Russell, et al, A family of ductile intermetallic compounds, Nat. Mater. 2 (2003)587-591.

[4] J.R. Morris, Y. Ye, Y-B. Lee, et al, Ab initio calculation of bulk and defect properties of ductile rare-earth intermetallic compounds, Acta Mater. 52 (2004) 4849-4852.

DOI: 10.1016/j.actamat.2004.06.050

[5] Q. Chen, S.B. Biner, Stability of perfect dislocations in rare-earth intermetalic compounds: YCu, YAg and YZn, Acta. Mater. 53 (2005)3215-3223.

DOI: 10.1016/j.actamat.2005.03.026

[6] Y.J. Shi, Y.L. Du, G. Chen, G. L . Chen, First-principle study on phase statbility and electronic structure of YCu, Phys. Lett. A 368(2007) 495-498.

DOI: 10.1016/j.physleta.2007.04.047

[7] Y.R. Wu, W.Y. Hu, S.C. Han, First-principles calculation of the elastic constants, the electronic density of states and the ductility mechanism of the intermetallic compounds: YAg, YCu and YRh, Physica B 403(2008)3792-3797.

DOI: 10.1016/j.physb.2008.07.009

[8] Y.R. Wu, W.Y. Hu, Energetic and properties of vacancies, anti-sites, and atomic defects (B, C, and N) in ductile B2-YM(M=Ag, Cu, Rh) intermetallics, Mater. Sci. Forum 689(2011) 91-94.

DOI: 10.4028/www.scientific.net/msf.689.91

[9] Q. Chen, M. Ji, C.Z. Wang, K.M. Ho, S.B. Biner, Core properties of dislocations in YCu and YAg B2 intermetallic compounds, Intermetallics, 18(2009)312-318.

DOI: 10.1016/j.intermet.2009.08.001

[10] Z. Zhang, A.M. Russell, S.B. Biner, et al, Fracture tougnness of polycrystalline YCu, DyCu and YAg, Intermetallics 13(2005) 559-564.

DOI: 10.1016/j.intermet.2004.09.008

[11] Y.R. Wu, W.Y. Hu, S.C. Han, Theoretical calculation of thermodynamic data for gold-rare earth alloys with the embedded-atom method, J. Alloys. Comp. 420(2006) 83-93.

DOI: 10.1016/j.jallcom.2005.10.020

[12] Y.R. Wu, W.Y. Hu, Molecular dynaimics simulations of thermodynamics, elastic constants and solid solution strengths for Mg-Gd alloys, Eur. Phys. J. B 57(2007) 305-312.

DOI: 10.1140/epjb/e2007-00164-9

[13] C. Colinet, The thermodynamic properties of rare-earth metallic systems, J. Alloy. Comp. 225(1995) 409-422.

[14] F.R. de Boer, R. Boom, W.C.M. Mattens, A.R. Miedema, A.K. Niessen. Coheion in Metals, Transition Metal Alloys, North-Holland, Amsterdam, (1988).

[15] S.F. Pugh, Relations between the elastic moduli and the plastic properties of polycrystalline pure metals, Philos. Mag. 45(1954) 823-843.

DOI: 10.1080/14786440808520496

[16] R. Wang, S.F. Wang, X.Z. Wu, A. P Liu, First-principles phonon calculations of thermodynamic properties for ductile rare-earth intermetallic compounds, Intermetallics, 19(2011)1599-1604.

DOI: 10.1016/j.intermet.2011.06.006