Effect of Heat Treatment on the Structure and Properties of EW75 Magnesium Alloy Plate

Abstract:

In this study, Mg-7Gd-5Y-1Nd-0.5Zr alloy (EW75) was produced by melting method and then press-forged into large size plate. The properties of the Mg-7Gd-5Y-1.2Nd-0.5Zr alloy were optimized through T6 heat treatment. The microstructures of alloy were observed by means of optical microscopy (OM), scanning electron microscopy (SEM). Its mechanical properties under different heat treatment conditions were determined by tensile tests. The results indicated that increasing the solid solution temperature and prolonging the solid solution time can both lead to the dissolution of second phase in the alloy back into the matrix. The solid solution temperature affects the dissolution process more than the solid solution time. Grain growth occurred during the solid solution process. The grain size of the matrix enlarges with the increase of solid solution temperature. The tensile test result showed that the tensile strength of the alloy was significantly improved after T6 heat treatment. Its tensile strength in the same direction was nearly 40% up after T6 heat treatment. The analysis shows that T6 heat treatment can effectively eliminate the larger deformed precipitates and beneficial to the formation of hard precipitates, which leads to an improvement in the alloys tensile strength.

• Periodical: Materials Science Forum (Volumes 747-748)
• Pages: 158-165
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.747-748.158
• Online since: February 2013
• Authors: Juan Qu, Kui Zhang, Ming Long Ma, Yong Jun Li, Xing Gang Li
• Keywords: Brittle Fracture, Mg-7Gd-5Y-1.2Nd-0.5Zr Alloy, Precipitate, T6-Heat Treatment

References

[1] Zheng liu, Kui Zhang, Xiaoqin Zeng, et al. Magnesium alloy theoretical basis and its application[M]. Beijing: Mechanical Industry Press, 2002: 16-18.

[2] Jinghuai Zhang, Dingxiang Tang, Hongjie Zhang, et al. The effect and application of rare earth elements in the magnesium alloy[J]. Rare Metals, 2008, 32(5): 659-667.

[3] Chen Zhenhua. Wrought magnesium alloy[M]. Beijing: Chemical Industry Press, (2005).

[4] Friderich H, Schumann S. Research for a new age of magnesium in the automotive industry [J]. Mater. Sci. Technol, 2001, 117 (1): 276.

[5] Hao Zhong, Peiying Liu, Tietao zhou. The applications and prospects of Magnesium and magnesium alloys in aerospace[J]. Aviation Maintenance & Engineering, 2002(4): 41-42.

[6] Zhang Kui, LI Xinggang, LI Yongjun, MA Minglong. Effect of Gd content on microstructure and mechanical properties of Mg-Y-RE-Zr alloys[J]. Trans Nonferrous Met Soc China, 2008, 18(s1): s12−s16.

DOI: 10.1016/s1003-6326(10)60166-5

[7] WANG J, MENG J, ZHANG D P, TANG D X, Effect of Y for enhanced age hardening response and mechanical properties of Mg-Gd-Y-Zr alloys[J]. Materials Science and engineering A, 2007, 456(1-2): 78-84.

DOI: 10.1016/j.msea.2006.11.096

[8] ANYANGWU I A, KAMADO S, KOJIMA Y. Aging characteristics and high temperature tensile properties of Mg-Gd-Y-Zr alloys[J]. Materials transactions, 2001, 42(7): 1206-1211.

DOI: 10.2320/matertrans.42.1206

[9] Peng Z.K., Zhang X.M., Chen J.M., et al. Grain Refining Mechanismin Mg-9Gd-4Y Alloys by Zirconium [J]. Materials Science and Technology, 2005, 21(6): 722-726.

DOI: 10.1179/174328405x43153

[10] Jianmin Zhang, Zefei Ma, Baohong Zhang. Strength effect of T6 heat treatment for Wrought magnesium alloy[J]. Hot Working Technology, 2010, 39(16): 136~137.

[11] Feng Wang, Zhi Wang, Zheng Liu, et al. effect of heat treatment for microstructure and properties of the die casting of Mg-8Gd-3Y-0. 5Zr alloy[J]. rare metal materials and engineering, 2010, 39(3): 502-505.

[12] L. Gao, R.S. Chen, E.H. Han. Effect of rare-earth elements Gd and Y on the solid solution strengthening of Mg alloys[J]. Journal of alloys and compounds, 2009, 481: 379-384.

DOI: 10.1016/j.jallcom.2009.02.131