Effect of Aging on Characterization of Sr-Modified Stir Cast A356/Al₂O₃ Composite

Abstract:

A356/Al₂O₃ composites with Sr modifier were produced by stir casting process. The composites were further heat treated to obtain light material with superior characteristics through precipitation hardening of Mg₂Si precipitate. The A356 alloy is reinforced with 10 %Vf Al₂O₃ micro particles. Small amount of Sr is added to modify eutectic silicon morphology from plate-like into fibrous. The composites were prepared by stir casting method in order to obtain dispersed reinforcement particulates within the matrix. T6 heat treatment is employed to the fabricated composites for 2, 4, 6, 8, and 10 hours of aging time to improve the properties. The result reveals that an optimum values of tensile strength, impact strength, hardness and wear rate are achieved by conducting 6 hours of aging. Longer than that, the properties will decline as a result of incoherent phase domination. Small amount of Sr is shown to be able to change the morphology of eutectic silicon from plate-like into fibrous. However, Fe-intermetallics formation, porosity, and negative effect from solution treatment due to improper technical condition during heat treatment are found to contribute on deterioration of mechanical properties of the material.

• Periodical: Key Engineering Materials (Volume 753)
• Pages: 33-38
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.753.33
• Online since: August 2017
• Authors: Anne Zulfia Syahrial*, Ahadya Pancasakti
• Keywords: Al A356, Al₂O₃, Sr Modifier, Stir Casting, T6 Heat Treatment

References

[1] Y. Mazaheri, F. Karimzadeh, M. Enayati, Development of Al356/Al2O3 Nanocomposite Coatings by High Velocity Oxy-fuel Technique, J. Mater. Sci. Tech. 29(9) (2013) 813-820.

DOI: 10.1016/j.jmst.2013.05.019

[2] S. J. Jahromi, A. Dehghan, S. Malekjani, Effects of optimum amount of Sr and Sb modifiers on tensile, impact, and fatigue properties of A356 Aluminum alloy, Iranian J. Sci. Tech. 28 (2004) 225-232.

[3] S. Sajjadi, M. T. Parizi, H. Ezatpour, A. Sedghi, Fabrication of A356 composite reinforced with micro and nano Al2O3 particles by a developed compocasting method and study of its properties, J. Alloy. Comp. 511 (2012) 226-231.

DOI: 10.1016/j.jallcom.2011.08.105

[4] I. El-Mahallawi, H. Abdelkader, L. Yousef, A. Amer, J. Mayer, A. Schwedt, Influence of Al2O3 nano-dispersions on microstructure features and mechanical properties of cast and T6 heat-treated Al Si hypoeutectic Alloys, Mater. Sci. Eng. A. 556 (2012).

DOI: 10.1016/j.msea.2012.06.061

[5] E. Candan, Effect of Alloying Elements to Aluminium on the Wettability of Al/SiC System, Turkish. J. Eng. Env. Sci. 26 (2002) 1-5.

[6] M. K. Surappa, P. Rohatgi, Preparation and properties of cast aluminium-cerarnic particle composites, J. Mater. Sci. 16(4) (1981) 983-993.

DOI: 10.1007/bf00542743

[7] T. Rajan, R. Pillai, B. Pai, Review - Reinforcement coatings and interfaces in aluminium metal matrix composites, J. Mater. Sci. 33 (1998) 3491-3503.

[8] G. Lin, H. W. Zhang, H. Z. Li, L. N. Guan, L. J. Huang, Effects of Mg content on microstructure and mechanical properties of SiC/Al-Mg composites fabricated by semi-solid stirring technique, Trans. Nonferr. Metal. Soc. China, 20(10) (2010).

DOI: 10.1016/s1003-6326(09)60385-x

[9] ASM International, ASM Handbook, in Vol. 4: Heat Treating, (1991).

[10] L. Pio, Effect of T6 Heat Treatment on the Mechanical Properties of Gravity Die Cast A356 Aluminium Alloy, J. Appl. Sci. 11 (2011) 2048-(2052).

DOI: 10.3923/jas.2011.2048.2052

[11] R. Chen, A. Iwabuchi, T. Shimizu, The effect of a T6 heat treatment on the fretting wear of a SiC particle-reinforced A356 aluminum alloy matrix composite, Wear, 238 (2000) 110-119.

DOI: 10.1016/s0043-1648(99)00328-2

[12] S. Pramod, Ravikirana, A. P. Rao, B. Murty, S. R. Bakshi, Effect of Sc addition and T6 aging treatment on the microstructure modification and mechanical properties of A356 alloy, Mater. Sci. Eng. A, 674 (2016) 438–450.

DOI: 10.1016/j.msea.2016.08.022

[13] K. Sekar, K. Allesu, M. A. Joseph, Effect of T6 heat treatment in the microstructure and mechanical properties of A356 reinforced with nano Al2O3 particles by combination effect of stir and squeeze casting, Proc. Mater. Sci. 5 (2014) 444-453.

DOI: 10.1016/j.mspro.2014.07.287

[14] J. Hashim, L. Looney, M. Hashmi, Metal Matrix Composites: production by the stir casting method, J. Mater. 92 (1999) 1-7.

DOI: 10.1016/s0924-0136(99)00118-1

[15] M. Surappa, Microstructure Evolution During Solidification of DRMMCs: State of Art, J. Mater. Proc. Tech. 63 (1997) 325-333.

DOI: 10.1016/s0924-0136(96)02643-x

[16] J. G. Conley, J. Huang, J. Asada, K. Akiba, Modeling the effects of cooling rate, hydrogen content, grain refiner and modifier on microporosity formation on Al A356 alloys, Mater. Sci. Eng. A, 285 (2000) 49-55.

DOI: 10.1016/s0921-5093(00)00665-1

[17] D. Ferdian, J. Lacaze, I. Lizarralde, A. Niklas, A. I. Fernandez-Calvo, Study of the Effect of Cooling Rate on Eutectic Modification in A356 Aluminium Alloys, Mater. Sci. Froum. 765 (2013) (2013).

DOI: 10.4028/www.scientific.net/msf.765.130

[18] M. Timpel, N. Wanderka, R. Schlesiger, T. Yamamoto, N. Lazarev, D. Isheim, G. Schmitz, S. Matsumura, J. Banhart, The role of strontium in modifying aluminium-silicon alloys, Acta Mater. 60 (2012) 3920-3928.

DOI: 10.1016/j.actamat.2012.03.031

[19] J. H. Peng, X. L. Tang, J. T. He, D. Y. Xu, Effect of heat treatment on microstructure and tensile properties of A356 alloys, Trans. Nonferr. Metal. Soc. China, 21 (2011) 1950-(1956).

DOI: 10.1016/s1003-6326(11)60955-2

[20] E. A. Elsharkawi, Effects of metallurgical parameters on the decomposition of π-AlFeMgSi phase in Al-Si-Mg alloys and its influence on the mechanical properties, Thesis - Universite du Quebec a Chicoutini, (2011).

DOI: 10.1522/030259014

[21] A. S. E. Samuel, H. Doty, S. Valtierra and F. Samuel, Intermetallic phases in Al-Si based cast alloys: new persective, (2014).

DOI: 10.1179/1743133613y.0000000083

[22] M. A. Elahi, S. G. Shabestari, Effect of various melt and heat treatment conditions on impact toughness of A356 aluminum alloy, Trans. Nonferr. Metal. Soc. China, 26 (2016) 956-965.

DOI: 10.1016/s1003-6326(16)64191-2

[23] S. Shivkumar, L. Wang, C. Keller, Impact Properties of A356-T6 Alloys, J. Mater. Eng. Perform. 3 (1994) 83.

[24] C. Estey, S. Cockcroft, D. Maijer and C. Hermesmann, Constitutive behaviour of A356 during the quenching operation, Mater. Sci. Eng. A, 383 (2004) 245–251.

DOI: 10.1016/j.msea.2004.06.004

[25] H. Long, J. Chen, C. Liu, D. Li, Y. Li, The negative effect of solution treatment on the age hardening of A356 alloy, Mater. Sci. Eng. A, 566 (2013) 112-118.

DOI: 10.1016/j.msea.2012.12.093