The role of Sn on microstructure, wear and corrosion properties of Al-5Zn-2.5Mg-1.6Cu-xSn alloy

Abstract

In the present investigation, Al-5Zn-2.5Mg - 1.6Cu -xSn (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 wt%) alloys were fabricated using melting and casting technique. The microstructures of the alloys were studied using optical, scanning electronic microscope/EDS and X-ray diffraction. The corrosion behaviour was performed using electrochemical measurements and immersion tests while the wear behaviour was carried out by pin-on-disc technique. The findings revealed that incorporating Sn to the Al-5Zn-2.5Mg alloy improved its corrosion and wear resistance due to refining the grains. The corrosion potentials shifted from −884 to −943,−955, −996,−1008 and −1012 mV (Ag / AgCl), while the coefficient of friction declined from 0.69 to 0.62 , 0.51 , 0.34, 0.29 and 0.22 with increment of Sn content from 0.0 to 0.2, 0.4. 0.6, 0.8 and 1.0 wt%, respectively. On the other hand, the results illustrated that the wear rate diminished from 4.42 *10 ^−3 to 1.47 * 10 ^−3 (mm ^3 /Nm) with increasing Sn from 0.0 to 1.0 wt%. Furthermore, the findings showed that increment of Sn content stimulated the uniform corrosion on the surface of alloys.

Keywords

• Al-Zn-Mg alloys
• grains refinements
• intermetallic precipitates
• hardness
• corrosion
• wear resistance