Effects of Sb and heat treatment on the microstructure of Al-15.5wt%Mg₂Si alloy

Abstract

The modification effects of alloying element Sb and heat treatment on Al-15.5wt%Mg₂Si alloy were investigated by Olympus microscopy (OM), scanning electron microscopy and energy disperse spectroscopy (SEM-EDS), and X-ray diffraction (XRD). It is found that Sb plays a significant role in shaping primary Mg₂Si phase and eutectic Mg₂Si phase in Al-15.5wt%Mg₂Si alloy. The Sb addition of about 1.0wt% makes the resultant alloy show the finest primary Mg₂Si phase and the eutectic Mg₂Si phase with well distribution. But further increasing the Sb content decreases the amount of primary Mg₂Si phase, and some segregated phases appear at regions between the grains. In addition, heat treatment can modify the microstructural feature of Sb-modified Al-15.5wt%Mg₂Si alloy in terms of obviously shortening the nodulizing time of primary Mg₂Si phase and eutectic Mg₂Si phase.

Keywords

aluminum alloys / intermetallics / heat treatment / antimony / microstructure / modification

References

[1] Zhang J, Fan Z, Wang YQ, Zhou BL. Microstructure and mechanical properties of in situ Al-Mg₂Si composites. Mater. Sci. Technol., 2000, 16(7–8): 913.

[2] Xiong W, Qin XY, Wang L. Progress in study on Mg₂Si intermetallic compound. Mater. Rev., 2005, 19(6): 4.

[3] Frommeyer G, Beer S, Von Oldenburg K. Microstructure and mechanical properties of mechanically alloyed intermetallic Mg₂Si-Al alloys. Z. Metallkd., 1994, 85(5): 372.

[4] Qin QD, Zhao YG, Zhou W, Cong PJ. Effect of phosphorus on microstructure and growth manner of primary Mg₂Si crystal in Mg₂Si/Al composite. Mater. Sci. Eng. A, 2007, 447(1–2): 186.

[5] Li C, Wu YY, Li H, Liu XF. Microstructural formation in hypereutectic Al-Mg₂Si with extra Si. J. Alloys Compds., 2009, 477(1–2): 212.

[6] Wang SR, Wang YZ, Ma R, Wang Y, Yang LY. Growth mechanism of primary silicon in cast hypoeutectic Al-Si alloys. Trans. Nonferrous Met. Soc. China, 2012, 22(6): 1264.

[7] Hegde S, Prabhu KN. Modification of eutectic silicon in Al-Si alloys. J. Mater. Sci., 2008, 43(9): 3009.

[8] Al-Helal K, Stone IC, Fan Z. Simultaneous primary Si refinement and eutectic modification in hypereutectic Al-Si alloys. Trans. Indian Inst. Met., 2012, 65(6): 663.

[9] Ren B, Liu ZX, Zhao RF, Zhang TQ, Liu ZY, Wang MX, Weng YG. Effect of Sb on microstructure and mechanical properties of Mg₂Si/Al-Si composites. Trans. Nonferrous Mct. Soc. China, 2010, 20(8): 1367.

[10] Ghorbani MR, Emamy M, Khorshidi R, Rasizadehghani J, Emami AR. Effect of Mn addition on the microstructure and tensile properties of Al-15%Mg₂Si composite. Mater. Sci. Eng. A, 2012, 550, 191.

[11] Zhang J, Fan Z, Wang YQ, Zhou BL. Microstructural development of Al-15wt%Mg₂Si in situ composite with mischmetal addition. Mater. Sci. Eng. A, 2000, 281(1–2): 104.

[12] Sun WC, Zhang SR, Hou AQ. Behavior of Rare Earth in Aluminum Alloys, 1992, Beijing, Norinco Group Press, 226.

[13] Li C, Wu YY, Li H, Liu XF. Morphological evo lution and growth mechanism of primary Mg₂Si phase in Al-Mg₂Si alloys. Acta Mater., 2011, 59(3): 1058.

[14] Zheng RJ, Jing XT, Lu ZX. Effects of Sb content on the structure and properties of Mg-6Al-6Si alloy. Foundry Technol., 2007, 28(4): 512.

[15] Wang ZB, Liu J, Yuan ZX. Effects of Sb on the microstructure and mechanical properties of magnesium alloy. Spec. Cast. Nonferrous Alloys, 2005, 25(9): 568.

[16] Sun FQ, Wang XD, Yan YW. Effects of Sb on microstructure of in-situ Mg₂Si/Mg composites. Spec. Cast. Nonferrous Alloys, 2005, 25(1): 18.

[17] Li CF, Wang J, Li K, Shu D, Sun BD. Microstructure refinement of in-situ Mg₂Si/Al composites. Chin. J. Nonferrous Met., 2004, 14(2): 233.

[18] Xiao JM. Alloy Phase and Phase Transition, 2003, Beijing, Metallurgical Industry Press, 115.