Microstructure Evolution of Al-Zn-Mg-Cu Alloy with Erbium during Homogenization

Abstract:

The microstructure evolution of Al-Zn-Mg-Cu alloy with erbium was studied by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) during homogenization process. The results showed that there were serious component segregation in the as-cast structure of the alloy, mainly composed of T(AlZnMgCu) , S(Al₂CuMg) and a small amount of Al₈Cu₄Er and Al₇Cu₂Fe. The overheating temperature of the alloy was 482.5 °C. After homogenized at 470 °C for 24 h, the dissolution of T(AlZnMgCu) phase and S(Al₂CuMg) phase reached to a balance, but the residual Al₈Cu₄Er phase could not be dissolved completely. Compared with single-stage homogenization, Al₃(Er,Zr) dispersion phase with smaller grain size and more uniform distribution can be obtained after two stage homogenization process of 400 °C for 8 h followed by 470 °C for 24 h. By comparing the residue of non-equilibrium eutectic phase, two-stage homogenization is the best.

• Periodical: Materials Science Forum (Volume 1035)
• Pages: 253-258
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1035.253
• Online since: June 2021
• Authors: Zheng Jie Tian, Bo Long Li*, Bo Hou Zhang, Peng Qi, Zuo-Ren Nie
• Keywords: Al₃(Er,Zr) Particles, Al-Zn-Mg-Cu Alloy, Homogenization, Microstructure Evolution

References

[1] Y. Liu, D.M. Jiang, B.Q. Li, T. Ying, J. Hu, Heating aging behavior of Al-8.35Zn-2.5Mg-2.25Cu alloy, Materials and Design. 60 (2014) 116-124.

DOI: 10.1016/j.matdes.2014.03.060

[2] T. Marlaud, A. Deschamps, F. Bley, W. Lefebvre, B. Baroux, Influence of alloy composition and heat treatment on precipitate composition in Al-Zn-Mg-Cu alloys, Acta Mater. 58 (2010) 248-260.

DOI: 10.1016/j.actamat.2009.09.003

[3] H.B. Wang, J.F. Huang, B. Yang, J.S. Zhang, Y.A. Zhang, B.Q. Xiong, Research status and development of super-strength Al-Zn-Mg-Cu alloy, Mater Res. 9 (2003) 1-4.

[4] W.B. Li, Q.L. Pan, Y.P. Xiao, Y.B. Xiao, Y.B. He, X.Y. Liu, Microstructural evolution of ultra-high strength Al-Zn-Cu-Mg-Zr alloy containing Sc during homogenization, Trans.Nonferrous Met. Soc. China. 21 (2011) 2127-2133.

DOI: 10.1016/s1003-6326(11)60984-9

[5] S.N. Samaras, G.N. Haidemenopoulos, J. Mater, Modelling of microsegregation and homogenization of 6061 extrudable Al-alloy, Process Technol. 194 (2007) 63-73.

DOI: 10.1016/j.jmatprotec.2007.03.126

[6] H. Wu, S.P. Wen, H. Huang, B.L. Li, X.L. Wu, K.Y. Gao, W. Wang, Z.R. Nie, Effects of homogenization on precipitation of Al3(Er,Zr) particles and recrystallization behavior in a new type Al-Zn-Mg-Er-Zr alloy, Materials Science and Engineering A. 689 (2017) 313-322.

DOI: 10.1016/j.msea.2017.02.071

[7] J.D. Robson, P.B. Prangnel, Dispersoid precipitation and process modelling in zirconium containing commercial aluminium alloys, Acta Materialia. 49 (2001) 599-613.

DOI: 10.1016/s1359-6454(00)00351-7

[8] C. Mondal, A.K. Mukhopadhyay, On the nature of T(Al2Mg3Zn3) and S (Al2CuMg) phases present in as-cast and annealed 7055 aluminum alloy, Materials Science and Engineering A. 139 (2005) 367-376.

DOI: 10.1016/j.msea.2004.09.013

[9] D. Xu, Z.H. Li, G.J. Wang, X.W. Li, X.Y. Lu, Y.A. Zhang, Y.Q. Fan, B.Q. Xiong, Phase transformation and microstructure evolution of an ultra-high strength Al-Zn-Mg-Cu alloy during homogenization, Materials Characterization. 131 (2017) 285-297.

DOI: 10.1016/j.matchar.2017.07.011

[10] H. Wu, S.P. Wen, J.T. Lu, Z.P. Mi, X.L. Zeng, H. Huang, Z.R. Nie, Microstructural evolution of new type Al-Zn-Mg-Cu alloy with Er and Zr additions during homogenization, Trans. Nonferrous Met. Soc. China. 27 (2017) 1476-1482.

DOI: 10.1016/s1003-6326(17)60168-7

[11] X.G. Fan, D.M. Jiang, Q.C. Meng, L. Zhong, The microstructural evolution of an Al-Zn-M-Cu alloy during homogenization, Materials Letters. 60 (2006) 1475-1479.

DOI: 10.1016/j.matlet.2005.11.049

[12] Y. Deng, Z.M. Yin, F.G. Cong, Intermetallic phase evolution of 7050 aluminum alloy during homogenization, Intermetallics. 26 (2012) 114-121.

DOI: 10.1016/j.intermet.2012.03.006

[13] X.G. Fan, D.M. Jiang, Q.C. Meng, Z. Li, The microstructural evolution of an Al-Zn-Mg-Cu alloy during homogenization, Materials Letters. 60 (2011) 1475-1479.

DOI: 10.1016/j.matlet.2005.11.049

[14] Z.K. Zhao, T.T. Zhou, P.Y. Liu, C.Q. Chen, TEM observation of Er phase in aging microstructure of Al-Zn-Mg-Cu-Li-Er alloy, Rare Metal Materials and Engineering. 33 (2004) 1109-1111.