Microstructure Evolution and Mechanical Properties of Rheocast A319 Aluminum Alloy Using Cooling Slope

Abstract:

A319 aluminum alloys are commonly used in automotive industry due to a combination of good fluidity and mechanical strength. In this present work, cooling slope (CS) rheocasting process was employed to produce A319 billets with near spherical morphology of primary Al phase. The dendritic primary phase in the cast A319 alloy had readily transformed into non-dendritic when the ingots were cast over a cooling plate from pouring temperatures between 620°C and 640°C and with cooling lengths of between 300 mm and 400 mm. The shear driven flow of the solidifying melt on the cooling slope wall promotes heterogeneous nucleation of α-Al phase and subsequent separation from there due to shear driven flow of the solidifying melt produced nearly spheroidal morphology of the primary phase in the microstructure. The results show that the best combination of pouring temperature and cooling length was found to be 630°C and 400 mm respectively. The hardness of the rheocast ingots improved to 85.3 HV from 81.8 HV in as-cast condition.

• Periodical: Applied Mechanics and Materials (Volume 663)
• Pages: 261-265
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.663.261
• Online since: October 2014
• Authors: Mohd Shukor Salleh*, M.Z. Omar, Junaidi Syarif, M.N. Mohammed, K.S. Alhawari
• Keywords: A319 Aluminum Alloy, Cooling Slope, Rheocast

References

[1] M.S. Salleh, M.Z. Omar, J. Syarif, M.N. Mohammed, Thermodynamic simulation on thixoformability of aluminium alloys for semi-solid processing, Int. J. of Mathematics and Computers in Simulation. 7, (2013) 286-293.

[2] B.C. Liao, Y.K. Park, H.S. Ding, Effects of rheocasting and heat treatmet on microstructure and mechanical properties of A356 alloy, Materials Science and Engineering A. 528 (2011) 986-995.

DOI: 10.1016/j.msea.2010.09.059

[3] M.S. Salleh, M.Z. Omar, J. Syarif, M.N. Mohammed, Thermodynamic modelling for thixoformability of Al-Si alloys for semisolid processing, Advanced Science Letters. 19 (2013) 3503-3507.

DOI: 10.1166/asl.2013.5205

[4] E. Rincon, H.F. lopez, M.M. Cisneros, H. mancha, M.A. Cisneros, Effect of temperature on the tensile properties of an as-cast aluminium alloy A319, Materials Science and Engineering A. 452-453 (2007) 682-687.

DOI: 10.1016/j.msea.2006.11.029

[5] M.S. Salleh, M.Z. Omar, J. Syarif, M.N. Mohammed, An overview of semisolid processing of aluminium alloys, ISRN Materials Science, 2013, pp.1-9.

DOI: 10.1155/2013/679820

[6] P. Das, S.K. Samanta, T. Ray, B.R.K. Venkatpathi, Mechanical properties and tensile fracture mechanism of rheocast A356 Al alloy using cooling slope, Advanced Materials Research. 585 (2012) 354-358.

DOI: 10.4028/www.scientific.net/amr.585.354

[7] M.N. Mohammed, M.Z. Omar, M.S. Salleh, K.S. Alhawari, Study on thixojoining process using partial remelting method, Advanced in Materials Science and Engineering, 2013 (2013) 1-8.

DOI: 10.1155/2013/251472

[8] Z. Fan, Semisolid metal processing, International Materials Reviews. 47 (2002) 49-85.

[9] M.A.M. Arif, M.Z. Omar, N. Muhamad, J. Syarif, P. Kapranos, Microstructural evolution of solid-solution-treated Zn-2Al in the semisolid state, J. of Materials Science & Technology. 29 (2013) 765-774.

DOI: 10.1016/j.jmst.2013.04.003

[10] J.R. Davis, ASM Specialty Handbook: Aluminum and Aluminum Alloys, America Society for Metals, Metals Park, OH, USA, (1993).