In the present study, the corrosion behaviour of A356 (Al-7Si-0.3Mg) alloy in 3.5% NaCl solution has been evaluated using cyclic/potentiodynamic polarization tests. The alloy was provided in the unmodified form and it was then modified with AlTi5B1 for grain refinement and with AlSr15 for Si modifications. These modifications yield to better mechanical properties. Tensile tests were performed. In addition, bifilm index and SDAS values were calculated and microstructure of the samples was investigated. As a result of the corrosion test, the Ecorr values for all conditions were determined approximately equal, and the samples were pitted rapidly. The degassing of the melt decreased the bifilm index (i.e. higher melt quality) and thereby the corrosion resistance was increased. The lowest corrosion rate was founded at degassing and as-received condition (3.9x10-3 mm/year). However, additive elements do not show the effect which degassing process shows.
 Chomsaeng, N., Haruta, M., Chairuangsri, T., Kurata, H., Isoda, S. & Shiojiri, M. (2010). HRTEM and ADF-STEM of precipitates at peak-ageing in cast A356 aluminum alloy. Journal of Alloys and Compounds. 496(1), 478-487.
 Tsai, Y.-C., Chou, C.-Y., Lee, S.-L., Lin, C.-K., Lin, J.-C. & Lim, S. (2009). Effect of trace La addition on the microstructures and mechanical properties of A356 (Al-7Si-0.35 Mg) aluminum alloys. Journal of alloys and compounds. 487(1), 157-162.
 Górny, M., Sikora, G. & Kawalec, M., (2016). Effect of Titanium and Boron on the Stability of Grain Refinement of Al-Cu Alloy. Archives of Foundry Engineering. 16(3), 35-38.
 Kori, S., Murty, B. & Chakraborty, M. (2000). Development of an efficient grain refiner for Al-7Si alloy. Materials Science and Engineering: A. 280(1), 94-104.
 Ma, T., Chen, Z., Nie, Z. & Huang, H. (2013). Microstructure of Al-Ti-B-Er refiner and its grain refining performance. Journal of Rare Earths. 31(6), 622-627. 10.1016/S1002-0721(12)60331-7.
 Mi, L., Wang, J.J. & Hu, Z.L., (2014). The research progress of TiB2 impacts on the refining effect of Al-Ti-B master alloy. Applied Mechanics and Materials. 391-395.
 Mohanty, P. & Gruzleski, J. (1996). Grain refinement mechanisms of hypoeutectic Al-Si alloys. Acta materialia. 44(9), 3749-3760.
 Qiu, K., Wang, R.C., Peng, C.Q., Wang, N.G., Cai, Z.Y. & Zhang, C. (2015). Effects of Mn and Sn on microstructure of Al-7Si-Mg alloy modified by Sr and Al-5Ti-B. Transactions of Nonferrous Metals Society of China (English Edition). 25(11), 3546-3552. 10.1016/S1003-6326(15)64075-4.
 Timelli, G., Camicia, G. & Ferraro, S. (2014). Effect of Grain Refinement and Cooling Rate on the Microstructure and Mechanical Properties of Secondary Al-Si-Cu Alloys. Journal of materials engineering and performance. 23(2): range of pages
 Zhang, Y.J., Ma, N.H., Li, X.F. & Wang, H.W., (2014). A new technology to improve the elongation of A356 alloy. in Solid State Phenomena. p. 450-454.
 Faraji, M., Eskin, D.G. & Katgerman, L. (2012). Grain refinement in hypoeutectic Al-Si alloys using ultrasonic vibrations. Foundry Trade Journal International, 186(3694): range of pages.
 Gnapowski, S., Tsunekawa, Y., Okumiya, M. & Lenik, K., (2013). Change of Aluminum Alloys Structure by Sono- Solidification. Archives of Foundry Engineering. 13(4), 39-42.
 Jian, X., Meek, T.T. & Han, Q. (2006). Refinement of eutectic silicon phase of aluminum A356 alloy using highintensity ultrasonic vibration. Scripta Materialia, 54(5): range of pages.
 Jian, X., Xu, H., Meek, T. & Han, Q. (2005). Effect of power ultrasound on solidification of aluminum A356 alloy. Materials letters, 59(2): range of pages.
 Li, J.-w., Momono, T., Fu, Y., Jia, Z. & Tayu, Y. (2007). Effect of ultrasonic stirring on temperature distribution and grain refinement in Al-1.65%Si alloy melt. Transactions of Nonferrous Metals Society of China, 17(4): range of pages. http://dx.doi.org/10.1016/S1003-6326(07)60158-7.
 Łągiewka, M. & Konopka, Z., (2012). The Influence of Material of Mould and Modification on the Structure of Alsi11 Alloy. Archives of Foundry Engineering. 12(1), 67-70.
 Tupaj, M., Orłowicz, A.W., Mróz, M., Trytek, A. & Markowska, O., (2016). Usable Properties of AlSi7Mg Alloy after Sodium or Strontium Modification. Archives of Foundry Engineering. 16(3), 129-132.
 Zhongwei, C. & Ruijie, Z. (2010). Effect of strontium on primary dendrite and eutectic temperature of A357 aluminum alloy. Research & Development: range of pages.
 Campbell, J., (2015). Complete Casting Handbook: Metal Casting Processes, Metallurgy, Techniques and Design: Elsevier Science.
 Dispinar, D., Akhtar, S., Nordmark, A., Di Sabatino, M. & Arnberg, L. (2010). Degassing, hydrogen and porosity phenomena in A356. Materials Science and Engineering: A, 527(16): range of pages.
 Dispinar, D. & Campbell, J. (2004). Critical assessment of reduced pressure test. Part 2: Quantification. International Journal of Cast Metals Research, 17(5): range of pages.
 Dispinar, D. & Campbell, J. (2007). Effect of casting conditions on aluminum metal quality. Journal of materials processing technology, 182(1): range of pages.
 Dispinar, D. & Campbell, J. (2011). Porosity, hydrogen and bifilm content in Al alloy castings. Materials Science and Engineering: A, 528(10): range of pages.
 Arrabal, R., Mingo, B., Pardo, A., Mohedano, M., Matykina, E. & Rodríguez, I. (2013). Pitting corrosion of rheocast A356 aluminum alloy in 3.5 wt.% NaCl solution. Corrosion Science, 73: range of pages.
 Osorio, W.R., Peixoto, L.C., Goulart, P.R. & Garcia, A. (2010). Electrochemical corrosion parameters of as-cast Al- Fe alloys in a NaCl solution. Corrosion Science, 52(9): rang of pages.
 Park, C., Kim, S., Kwon, Y., Lee, Y. & Lee, J. (2005). Mechanical and corrosion properties of rheocast and lowpressure cast A356-T6 alloy. Materials Science and Engineering: A, 391(1): range of pages.
 Dispinar, D., Nordmark, A., Voje, J. & Arnberg, L. (2009). Influence of hydrogen content and bi-film index on feeding behaviour of Al-7Si. in 138th TMS Annual Meeting, Shape Casting: 3rd International Symposium, San Francisco, California, USA,(February 2009). (Page Range).