First-Principles Investigation of Laves Phases in Mg-Al-Ca System

Abstract:

Recent experiments and first-principles calculations in the literature revealed the existence of a C36 laves phase in the Al2Ca-Mg2Ca pseudo-binary system in addition to the C14-Mg2Ca and C15-Al2Ca laves phases. In the present work, special quasirandom structures (SQS) for all three laves phases were constructed. The structures possess local pair and multisite correlation functions that mimic those of the corresponding random structures. First-principles calculations were carried out based on the SQS developed to predict the enthalpy of formation in the Al2Ca-Mg2Ca pseudo-binary system. It was observed that the enthalpy of formation of C36 is very close to that of C14 at the Mg2Ca end and decreases with the addition of small amount of Al, while the enthalpy of formation of C14 increases with the addition of Al. It is thus energetically plausible that C36 is stable in the Al2C- Mg2Ca pseudo-binary system.

• Periodical: Materials Science Forum (Volumes 488-489)
• Pages: 169-176
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.488-489.169
• Online since: July 2005
• Authors: Yu Zhong, Alan A. Luo, Jorge O. Sofo, Zi Kui Liu
• Keywords: First-Principle, Mg₁₇Al₁₂Al₂Ca, Mg-Al-Ca Alloy

References

[1] A. A. Luo, M. P. Balogh and B. R. Powell, Metall. Mater. Trans. A, 33, (2002) 567-574.

[2] M. O. Pekguleryuz and E. Baril, Development of creep resistant Mg-Al-Sr alloys, Minerals, Metals and Materials Society/AIME, Magnesium Technology, New Orleans, LA, USA (2001), pp.119-125.

DOI: 10.1002/9781118805497.ch22

[3] A. Luo, M. P. Balogh and B. R. Powell, Tensile creep and microstructure of magnesium-aluminum-calcium alloys for powertrain applications: Part 2 of 2, SAE2001 (Detroit, MI, 2001).

DOI: 10.4271/2001-01-0423

[4] J. A. Catterall and R. J. Pleasance, J. Inst. Metals, 86, (1957-58) 189-192. Figure 4: First principles calculation results from one unit cell, supercell, and coupled with SQS structures for C15, C14, and C36 laves phases. Al2Ca 0 0. 5 1 1. 5 2 2. 5 3 0 0. 2 0. 4 0. 6 0. 8 1 Mg2Ca Enthalpy of Formation, (kJ/mol) C15-unit cell C15-SQS C15-supercell Al2Ca -1. 00 -0. 50 0. 00 0. 50 1. 00 1. 50 2. 00 2. 50 3. 00 3. 50 0 0. 2 0. 4 0. 6 0. 8 1 Mg2CaEnthalpy of Formation, kJ/mol C15 C14 C36 Figure 4: First principles calculation results for C15 laves phases with one unit cell, supercell, and SQS.

DOI: 10.1002/pssb.2220770223

[5] R. Ninomiya, T. Ojiro and K. Kubota, Acta Metall. Mater., 43, (1995) 669-674.

[6] M. Liu, Q. Wang, Z. Liu, G. Yuan, G. Wu, Y. Zhu and W. Ding, J. Mater. Sci. Lett., 21, (2002) 1281-1283.

[7] S. Amerioun, S. I. Simak and U. Haussermann, Inorganic Chemistry, 42, (2003) 1467-1474.

[8] Y. Zhong, A. Luo, J. Sofo and Z. K. Liu, Laves Phases in Mg-Al-Ca Alloys, A. Luo, Ed., Magnesium Technology 2004, Charlotte, NC, USA (2004), pp.317-323.

[9] A. Zunger, S. H. Wei, L. G. Ferreira and J. E. Bernard, Phys Rev Lett, 65, (1990) 353-356.

[10] S. H. Wei, L. G. Ferreira, J. E. Bernard and A. Zunger, Phys Rev B, 42, (1990) 9622-9649.

[11] K. C. Hass, L. C. Davis and A. Zunger, Phys Rev B, 42, (1990) 3757-3760.

[12] C. Jiang, C. Wolverton, J. Sofo, L. -Q. Chen and Z. -K. Liu, Physical Review B (Condensed Matter and Materials Physics), 69, (2004) 214202.

[13] Z. W. Lu, S. H. Wei and A. Zunger, Phys Rev B, 44, (1991) 3387-3390.

[14] Z. W. Lu, S. H. Wei and A. Zunger, Phys Rev B, 45, (1992) 10314-10330.

[15] D. Vanderbilt, Phys. Rev. B, 41, (1990) 7892-7895.

[16] G. Kresse and J. Hafner, J. Phys. -Condes. Matter, 6, (1994) 8245-8257.

[17] G. Kresse and J. Hafner, Phys. Rev. B, 47, (1993) 558-561.

[18] G. Kresse, Thesis, Technische Universitat Wien (1993).

[19] G. Kresse and J. Furthmuller, Phys. Rev. B, 54, (1996) 11169-11186.

[20] G. Kresse and J. Furthmuller, Comput. Mater. Sci., 6, (1996).