Experimental Study on Phase Diagram in the Vicinity of X or W Phase in the Mg-Zn-Y Ternary System

Abstract:

To elucidate the phase equilibria in the vicinity of the X or W phase in the Mg-Zn-Y ternary system, five Mg-Zn-Y ternary alloys containing the X or W phase were prepared and isothermally heat-treated to reach thermodynamic equilibrium. The microstructure and chemical compositions of the equilibrium phases of the alloys were analyzed. Furthermore, the crystal structure of the W phase was investigated, and the liquidus temperatures of the alloys were examined using differential thermal analysis. The results showed that the X phase can be crystallized not by a eutectic reaction, as reported previously, but by a peritectic reaction. They also showed that the W phase has the Heusler-type crystal structure with a stoichiometric composition of Mg₁Zn₂Y₁, and that Mg and Zn in the W phase can be substituted for each other. The Mg-Zn-Y ternary phase diagram was calculated using an assessed CALPHAD thermodynamic database based on the experimental results of the present study, and compared with a recently reported phase diagram.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 1170-1175
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.1170
• Online since: January 2012
• Authors: T. Horiuchi, H. Ikee, A. Hamaya, S. Minamoto, S. Nomoto, Seiji Miura
• Keywords: CALPHAD, Mg-Zn-Y, Phase Diagram, W Phase, X Phase

References

[1] I. J. Polmear: Mater. Sci. Technol., 42 (1994), 1-16.

[2] Y. Kawamura, K. Hayashi, A. Inoue and T. Masumoto: Mater. Trans., 42 (2001), 1172-1176.

[3] A. Inoue, Y. Kawamura, M. Matsushita, K. Hayashi and J. Koike: J. Mater. Res., 16 (2001), 1894-(1900).

[4] E. Abe, Y. Kawamura, K. Hayashi and A. Inoue: Acta Mater., 50 (2002), 3845-3857.

[5] C. Sanchez, G. Nussbaum, P. Azavant and H. Octor: Mater. Sci. Eng., A221 (1996), 48-57.

[6] T. Itoi, T. Seimiya, Y. Kawamura and M. Hirohashi: Scr. Mater., 51 (2004), 107-111.

[7] S. Yoshimoto, M. Yamasaki and Y. Kawamura: Mater. Trans., 47 (2006), 959-965.

[8] S. Fudetani, T. Itoi, T. Kubo, Y. Kawamura and M. Hirohashi: Mater. Trans., 50 (2009), 349-353.

[9] E. M. Padezhnova, E. V. Mel'nik, R. A. Miliyevskiy, T. V. Dobatkina and V. V. Kinzhibalo: Russian Metall., 4 (1982), 185-188.

[10] B. N. Zaselyan, P. Y. Sal'dau and S. K. Afanas'yev: Russian Metall., 6 (1968), 130-132.

[11] G. Shao, V. Varsani, Y. Wang, M. Qian and Z. Fan: Intermetallics, 14 (2006), 569-602.

[12] G. Shao, V. Varsani and Z. Fan: Calphad, 30 (2006), 286-295.

[13] T. Horiuchi, A. Ono, K. Yoshioka, T. Watanabe, K. Ohkubo, S. Miura, T. Mohri and S. Tamura: Mater. Trans., 49 (2008), 2247-2253.

DOI: 10.2320/matertrans.maw200822

[14] A. P. Tsai, Y. Murakami and A. Niikura: Phil. Mag., A80, 5 (2000), 1043-1054.

[15] J. -O. Andersson, T. Helander, L. Hoglund, P. Shi and B. Sundman: Calphad, 26 (2002), 273-312.