Research on High Pressure Solidification Microstructure and the Microhardness of Al-Mg-Zn Alloy

Abstract:

The solidification microstructure and the microhardness of Al-11Mg-4.5Zn alloy under high pressure were researched by optical microscope, scanning electron microscope (SEM), X-ray diffraction(XRD) and microhardness tester. The results revealed that high pressure solidification refined the dendrite structure, and made the primary dendrite arms grow long. The alloy all consisted of α-Al phase and Mg₃₂(Al, Zn)₄₉ phase whether under normal pressure or high pressure solidification conditions. However, the morphology of the Mg₃₂(Al, Zn)₄₉ phases changed from fork-like of normal pressure to the graininess of high pressure, the size of them reduced, and that of the amount decreased. Furthermore, the solid solubility of Mg and Zn in α-Al phase increased comparing with those of normal pressure, and they were the largest at 4GPa high pressure, reaching 11.37% and 4.15%, respectively. The microhardness of Al-Mg-Zn alloy had an increment with the pressure increasing.

• Periodical: Advanced Materials Research (Volumes 554-556)
• Pages: 565-569
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.554-556.565
• Online since: July 2012
• Authors: Zhen Ling Wang, Tao Zhang, Yue Bo Zhou, Yu Cheng Yu
• Keywords: Al-Mg-Zn Alloy, High Pressure Solidification, Microhardness, Microstructure

References

[1] Wang zhenling, wang hongwei, wei zunjie, et al. High pressure solidification microstructure and stability of Al-9.6Mg alloy ,The Chinese Journal of Nonferrous Metals. 17(3)(2007)384-389 (in Chinese)

[2] Yu Xi-feng, Zhang Guo-zhi, Xiao Han-jie, et al. Microstructure changes and growth mechanism of hypoeutectic Al-Si alloy solidified at high pressure, Chinese Journal of Materials Research, 14(2000) 141-144. (in Chinese)

[3] Zhang Guo-zhi, Yu Xi-feng, Wang Xiang-yang, et al. Non-equilibrium microstructure of Al-Si alloy solidified at superhigh pressure, Acta Metallurgica Sinica, 35(3)(1999)285-288(in Chinese)

[4] R.Xu, H.Zhao, J.Li, et al. Microstructures of the eutectic hypereutectic Al-Ge alloys solidified under different pressures, Mater. Lett, 60(2006)783-785

DOI: 10.1016/j.matlet.2005.10.012

[5] Y.S. Han, D.H. Kim, H.I. Lee. Effect of Applied Pressure during Solidification on the Microstructure Refinement in an Al-Cu alloy, Scr.Metall.Mater, 31(12)(1994)1623-1628

DOI: 10.1016/0956-716x(94)90453-7

[6] Z.-L.Wang, H.-W.Wang, Z.-J.Wei, L.Cao. Solidification characteristics of Al-9.6mass%Mg alloy solidified under 4GPa high pressure , Journal of Cast Metals Research, 19(6)(2006)349-355

DOI: 10.1179/136404606x157809

[7] M. C. Flemings. Solidification Processing, The Maple Press Company., New York,1974, p.266.

[8] Batashef A E. ed.in Crystallization of Metal and Alloys at Pressure. trans by Zhang Jin-sheng, Luo Shou-yi. Harbin Institute of Technology Publisher., Harbin, 1987, p.23