Effect of Sr and Ti addition on the corrosion behavior of Al-7Si- 0.3Mg alloy

摘要

In the present study, the corrosion behavior of A356 (Al-7Si-0.3Mg) alloy in 3.5%rnNaCl solution has been evaluated using cylic/potantiodynamic polarization tests. Thernalloy was provided in the unmodified form and it was then modified with AlTi5B1 forrngrain refinement and with AlSr15 for Si modifications. These modifications yield tornbetter mechanical properties. Tensile tests were performed. In addition, bifilm indexrnand SDAS values were calculated and microstructure of the samples wasrninvestigated. As a result of the corrosion test, the Ecorr values for all conditions wererndetermined approximately equal, and the samples were pitted rapidly. The degassingrnof the melt decreased the bifilm index (i.e. higher melt quality) and thereby therncorrosion resistance was increased. The lowest corrosion rate was founded atrndegassing and as-received (T2) condition (3,9×10~(-3) mm/year). However, additivernelements do not show the effect which degassing process shows.