The Influence of Heat Treatment on the Microstructure and Hardness of Mg-5Si-7Sn-5Mn Alloy

Abstract:

The microstructure and hardness of as-cast Mg-5Si-7Sn-5Mn alloy after solution and ageing treatments is presented in this paper. It was found that the microstructure of as-cast alloy. is composed of primary dendrites crystals of Mg₂Si phase, α-Mg matrix, long needle-like precipitates of Mn₅Si₃, Chinese script particles of Mg₂Si phase and irregular Mg₂Sn phase. The solution treatment at 500°C causes the dissolution of the Mg₂Sn phase in the α-Mg magnesium solid solution, whereas the remaining intermetallic compounds are stable in this temperature. The hardness of alloy increases from 73 HV2 to 96 HV2 at 250°C. The increase in hardness is a result of the formation of the lath-like precipitates of Mg₂Sn phase within the α-Mg matrix.

• Periodical: Solid State Phenomena (Volume 229)
• Pages: 83-88
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.229.83
• Online since: April 2015
• Authors: Tomasz Rzychoń*, Bartosz Chmiela, Adrian Mościcki, Bartłomiej Dybowski, Sylwia Jendrysko
• Keywords: In Situ Composite, Mg₂Si Phase, Mg-Si Alloy, Mg-Si-Sn-Mn Alloy, Microstructure

References

[1] Y. Pan, X. Liu, H. Yang, Microstructural formation in a hypereutectic Mg–Si alloy, Mater. Charact. 55 (2005) 241– 247.

DOI: 10.1016/j.matchar.2005.07.009

[2] N. Zheng, H.Y. Wang, Z.H. Gu, W. Wang, Q.C. Jiang, Development of an effective modifier for hypereutectic Mg–Si alloys, J. Alloys Compd. 463 (2008).

DOI: 10.1016/j.jallcom.2007.08.082

[3] F. Mirshahi, M. Meratian, High temperature tensile properties of modified Mg/Mg2Si in situ composite, Mater. Des. 33 (2012) 557–562.

DOI: 10.1016/j.matdes.2011.05.001

[4] A.A. Luo, Recent magnesium alloy development for elevated temperature applications, Int. Mater. Reviews 49(1) (2003) 13–30.

[5] T. Rzychoń, Characterization of Mg-rich clusters in the C36 phase of the Mg-5Al-3Ca-0. 7Sr-0. 2Mn alloy, J. Alloys Compd. 598 (2014) 95-105.

DOI: 10.1016/j.jallcom.2014.02.029

[6] K.N. Braszczyńska-Malik, Discontinuous and continuous precipitation in magnesium-aluminium type alloys, J. Alloys Compd. 477 (2009) 870–876.

DOI: 10.1016/j.jallcom.2008.11.008

[7] A. Kiełbus, T. Rzychoń, Structural stability of Mg–6Al–2Sr magnesium alloy, Solid State Phenom. 176 (2011) 75-82.

DOI: 10.4028/www.scientific.net/ssp.176.75

[8] T. Rzychoń, B. Adamczyk-Cieślak, Microstructure and creep resistance of Mg-Al-Ca-Sr alloys, Arch. Metall. Mater. 59 (2014) 327-332.

DOI: 10.2478/amm-2014-0054

[9] T. Rzychoń, A. Kiełbus, L. Lityńska-Dobrzyńska, Microstructure, microstructural stability and mechanical properties of sand-cast Mg-4Al-4RE alloy, Mater. Charact. 83 (2013) 21-34.

DOI: 10.1016/j.matchar.2013.06.001

[10] T. Rzychoń, A. Kiełbus, Microstructure and tensile properties of sand cast and die cast AE44 Magnesium Alloy, Arch. Metall. Mater. 53 (2008) 901-907.

[11] T. Rzychoń, J. Szala, A. Kiełbus, Microstructure, castability, microstructural stability and mechanical properties of ZRE1 magnesium alloy, Arch. Metall. Mater. 57 (2012) 254-252.

DOI: 10.2478/v10172-012-0018-3

[12] A. Kiełbus, T. Rzychoń, L. Lityńska-Dobrzyńska, G. Dercz, Characterization of β and Mg41Nd5 equilibrium phases in Elektron 21 magnesium alloy after long-term annealing, Solid State Phenom. 163 (2010) 106-109.

DOI: 10.4028/www.scientific.net/ssp.163.106

[13] T. Rzychoń, A. Kiełbus, M. Serba, The influence of pouring temperature on the microstructure and fluidity of Elektron 21 and WE54 magnesium alloys, Arch. Metall. Mater. 55, (2010) 7-13.

[14] B. Dybowski, A. Kiełbus, R. Jarosz, J. Paśko, The Microstructure of Elektron21 and WE43 Magnesium Casting Alloys after Subsequent Melting Process Operations, Solid State Phenom. 211 (2013) 65-70.

DOI: 10.4028/www.scientific.net/ssp.211.65

[15] A. Kiełbus, T. Rzychoń, The intermetallic phases in sand casting magnesium alloys for elevated temperature, Materials Sci. Forum 690 (2011) 214-217.

DOI: 10.4028/www.scientific.net/msf.690.214

[16] L. Wang, E. Guo, B. Ma, Modification effect of lanthanum on primary phase Mg2Si in Mg–Si alloys, J. Rare Earth 26 (2008) 105–109.

DOI: 10.1016/s1002-0721(08)60047-2

[17] Q.C. Jiang, H.Y. Wang, Y. Wang, B.X. Ma, J.G. Wang, Modification of Mg2Si in Mg–Si alloys with yttrium, Mater. Sci. Eng. A 392 (2005) 130–135.

DOI: 10.1016/j.msea.2004.09.007

[18] Q.D. Qin, Y.G. Zhao, C. Liu, P.J. Cong, W. Zhou, Strontium modification and formation of cubic primary Mg2Si crystals in Mg2Si/Al composite, J. Alloys Compd. 454 (2008) 142–146.

DOI: 10.1016/j.jallcom.2006.12.074

[19] H.Y. Wang, Q.C. Jiang, B.X. Ma, Y. Wang, J.G. Wang, J.B. Li, Modification of Mg2Si in Mg–Si alloys with K2TiF6, KBF4 and KBF4 + K2TiF6, J. Alloy Compd. 387 (2005) 105–108.

DOI: 10.1016/j.jallcom.2004.06.027

[20] M. Yang, F. Pan, J. Liang Bai, Comparison of Sb and Sr on modification and refinement of Mg2Si phase in AZ61–0. 7Si magnesium alloy, Trans. Nonferr. Metal. Soc. China 19 (2009) 287–292.

DOI: 10.1016/s1003-6326(08)60266-6

[21] E.J. Guo, B.X. Ma, L.P. Wang, Modification of Mg2Si morphology in Mg–Si alloys with Bi, J. Mater. Process. Technol. 206 (2008) 161–166.

DOI: 10.1016/j.jmatprotec.2007.12.038

[22] M.A. Gibson, X. Fang, C.J. Bettles, and C.R. Hutchinson, The effect of precipitate state on the creep resistance of Mg–Sn alloys, Scripta Mater. 63 (2010) 899–902.

DOI: 10.1016/j.scriptamat.2010.07.002