Al-Mn-Zn ternary system is experimentally investigated at 400°C using diffusion couples and key alloys. Phase relationships and homogeneity ranges are determined for binary and ternary compounds using EPMA, SEM/EDS, and XRD. Reported ternary compound T3 (Al11Mn3Zn2) is confirmed in this study and is denoted as τ2 in this paper. Two new ternary compounds (τ1 and τ3) are observed in this system at 400°C. τ1 is determined as a stoichiometric compound with the composition of Al31Mn8Zn11. τ3 has been found to have homogeneity range of AlxMnyZnz ( ？at%; ？at%; ？at%). The binary compounds Al4Mn and Al11Mn4 exhibit limited solid solubility of around 6？at% and 4？at% Zn, respectively. Terminal solid solution Al8Mn5 is found to have maximum ternary solubility of about 10？at% Zn. In addition, ternary solubility of Al-rich β-Mn′ at 400°C is determined as 4？at% Zn. Zn-rich β-Mn′′ has a ternary solubility of 3？at% Al. The solubility of Al in Mn5Zn21 is measured as 5？at%. Based on the current experimental results, the isothermal section of Al-Mn-Zn ternary system at 400°C has been constructed. 1. Introduction Automotive industry represents one of the most important markets for aluminum alloys. The use of aluminum and its alloys offers considerable potential to reduce the weight of an automobile body or engine without compromising performance and safety [1]. Many different elements including Mg, Cu, Zn, Mn, Si, and so forth are used to improve the properties of Al alloy for specific applications. Al-Zn based alloys have high strength and hardness, improved creep, wear resistance, and low density. It is well known that a small amount of Mn added to Al alloys plays a positive role in improving the fracture toughness, recrystallization, grain refinement, and resistance to stress corrosion fatigue of these alloys [1–3]. Because the Al-Mn-Zn system is an important ternary system for the development of Al alloys, it is essential to understand the phase relationships in the system. In addition, this system is an essential subsystem for AZ, AM-series magnesium alloys, high strength steels, and for galvanizing-related alloy systems [4, 5]. The three constituent binary systems were reasonably studied. Khan and Medraj [6] reevaluated the Al-Mn system which was in good agreement with most of the experimental results [7–10]. From their work [6], thermodynamic calculation almost reproduced the EPMA results of Minamino et al. [11]. Their calculation was consistent with the observation of Okamoto [12] who suggested a smooth continuous liquidus curve between the terminal δ-phase (BCC)
References
[1]
G. S. Cole and A. M. Sherman, “Light weight materials for automotive applications,” Materials Characterization, vol. 35, no. 1, pp. 3–9, 1995.
[2]
S. W. Nam and B. O. Kong, “Development of weldable high strength alalloy,” KOSEF Technical Report, 1993.
[3]
H. S. Cho and S. W. Nam, “A study of the low cycle fatigue properties of weldable Al-Zn-Mg-Mn Alloy and Al 7039 in various environments,” Journal of Korean Institute of Metals and Materials, vol. 32, no. 7, pp. 765–770, 1994.
[4]
M. Ohno, D. Mirkovic, and R. Schmid-Fetzer, “Liquidus and solidus temperatures of Mg-rich Mg-Al-Mn-Zn alloys,” Acta Materialia, vol. 54, no. 15, pp. 3883–3891, 2006.
[5]
N. Gao, Y. H. Liu, and N.-Y. Tang, “An experimental study of the liquid domain of the Zn-Fe-Al-Mn quaternary system at 460°C,” Journal of Phase Equilibria and Diffusion, vol. 31, no. 6, pp. 523–531, 2010.
[6]
M. A. Khan and M. Medraj, “Thermodynamic description of the Mg-Mn, Al-Mn and Mg-Al-Mn systems using the modified quasichemical model for the liquid phases,” Materials Transactions, vol. 50, no. 5, pp. 1113–1122, 2009.
[7]
C. Müller, H. Stadelmaier, B. Reinsch, and G. Petzow, “Metallurgy of the magnetic τ-phase in Mn-Al and Mn-Al-C,” Zeitschrift fuer Metallkunde, vol. 87, no. 7, pp. 594–597, 1996.
[8]
A. Shukla and A. D. Pelton, “Thermodynamic assessment of the Al-Mn and Mg-Al-Mn systems,” Journal of Phase Equilibria and Diffusion, vol. 30, no. 1, pp. 28–39, 2009.
[9]
H. Kono, “On the ferromagnetic phase in manganese-aluminum system,” Journal of the Physical Society of Japan, vol. 13, no. 12, pp. 1444–1451, 1958.
[10]
W. Koster and E. Wachtel, “Constitution and magnetic properties of aluminum-manganese alloys with more than 5 At. % Mn,” Zeitschrift fuer Metallkunde, vol. 51, pp. 271–280, 1960.
[11]
Y. Minamino, T. Yamane, H. Araki et al., “Solid solubilities of manganese and titanium in aluminum at 0.1 MPa and 2.1 GPa,” Metallurgical Transactions A, vol. 22, no. 3, pp. 783–786, 1991.
[12]
H. Okamoto, “Al-Mn (Aluminum-Manganese),” Journal of Phase Equilibria, vol. 18, no. 4, pp. 398–399, 1997.
[13]
M. A. Taylor, “Intermetallig phases in the aluminiummanganese binary system,” Acta Metallurgica, vol. 8, no. 4, pp. 256–262, 1960.
[14]
S. Wasiur-Rahman and M. Medraj, “A thermodynamic description of the Al-Ca-Zn ternary system,” Calphad, vol. 33, no. 3, pp. 584–598, 2009.
[15]
H. Okamoto and L. E. Tanner, “The Mn-Zn (Manganese-Zinc) system,” Bulletin of Alloy Phase Diagrams, vol. 11, no. 4, pp. 377–384, 1990.
[16]
S. Tezuka, S. Sakai, and Y. Nakagawa, “Ferromagnetism of Mn-Zn alloy,” Journal of the Physical Society of Japan, vol. 15, no. 5, p. 931, 1960.
[17]
Y. Nakagawa and T. Hori, “Magnetic transition and crystal distortion in MnHg and MnZn3,” Journal of the Physical Society of Japan, vol. 17, no. 8, pp. 1313–1314, 1962.
[18]
B. Henderson and R. J. M. Willcox, “Lattice spacing relationships in hexagonal close-packed Silver-Zinc-Manganese alloys,” Philosophical Magazine, vol. 9, no. 101, pp. 829–846, 1964.
[19]
R. A. Farrar and H. W. King, “Axial ratios and solubility limits of H.C.P. and phases in the systems CdMn and ZnMn,” Metallography, vol. 3, no. 1, pp. 61–70, 1970.
[20]
J. L. Liang, Y. Du, C. Z. Liao et al., “Experimental investigation on the phase equilibria of the Mn-Ni-Zn system at 400°C,” Journal of Alloys and Compounds, vol. 489, no. 2, pp. 362–368, 2010.
[21]
J. L. Liang, Y. Du, Q. Z. Zhao et al., “Determination of the phase equilibria in the Mn-Sn-Zn system at 500° C,” Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, vol. 40, no. 12, pp. 2909–2918, 2009.
[22]
H. Xu, X. Xiong, L. Zhang, Y. Du, and P. Wang, “Phase equilibria of the Mn-Si-Zn system at 600°C,” Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, vol. 40, no. 9, pp. 2042–2047, 2009.
[23]
E. Gebhardt, “Die zinkecke des dreistoffsystems zink-aluminium-mangan,” Zeitschrift für Metallkunde, vol. 34, pp. 259–263, 1942.
[24]
G. V. Raynor and D. W. Wakeman, “The intermetallic compound phases of the system Aluminium-Manganese-Zinc,” Proceedings of the Royal Society of London A: Mathematical and Physical Sciences, vol. 190, no. 1020, pp. 82–101, 1947.
[25]
K. Robinson, “The determination of the crystal structure of Ni4Mn11Al60,” Acta Crystallographica, vol. 7, part 6-7, pp. 494–497, 1954.
[26]
A. Damjanovic, “The structure analysis of the T3 (A1MnZn) compound,” Acta Crystallographica, vol. 14, pp. 982–987, 1961.
[27]
R. J. Schaefer, L. A. Bendersky, D. Shechtman, W. J. Boettinger, and F. S. Biancaniello, “Icosahedral and decagonal phase formation in Al-Mn Alloys,” Metallurgical transactions A, vol. 17, no. 12, pp. 2117–2125, 1986.
[28]
A. Singh, S. Ranganathan, and L. A. Bendersky, “Quasicrystalline phases and their approximants in Al-Mn-Zn alloys,” Acta Materialia, vol. 45, no. 12, pp. 5327–5336, 1997.
[29]
J. S. Kirkaldy and L. C. Brown, “Diffusion behavior in the ternary, multiphase systems,” Canadian Metallurgical Quarterly, vol. 2, no. 1, pp. 90–115, 1963.
[30]
J. B. Clark, “Conventions for plotting the diffusion paths in multiphase ternary diffusion couples on the isothermal section of a ternary phase diagram,” Transactions of the Metallurgical Society of AIME, vol. 227, pp. 1250–1251, 1963.
[31]
A. A. Kodentsov, G. F. Bastin, and F. J. J. van Loo, “The diffusion couple technique in phase diagram determination,” Journal of Alloys and Compounds, vol. 320, no. 2, pp. 207–217, 2001.
[32]
M. A. Khan, Thermodynamic modeling of the Mg–Mn–(Al, Zn) systems [M.S. thesis], Concordia University, 2009.
[33]
PANalytical, Ver2.2b (2.2.2), PANalytical, Almelo, The Netherlands, 2006.
[34]
H. Putz and K. Brandenburg, Pearson's Crystal Data, Crystal Structure Database for Inorganic Compounds, CD-ROM Software Version 1.3.
[35]
P. Ghosh and M. Medraj, “Thermodynamic calculation of the Mg-Mn-Zn and Mg-Mn-Ce systems and re-optimization of their constitutive binaries,” Calphad: Computer Coupling of Phase Diagrams and Thermochemistry, vol. 41, pp. 89–107, 2013.
[36]
A. Prince, Alloy Phase Equilibria, Elsevier, Amsterdam, The Netherland, 1966.
[37]
L. Y. H. John, “Schreinemakers rule as applied to non-degenerate ternary systems,” The Journal of Young Investigators, vol. 19, no. 11, 2009.
