Investigation on the tribocorrosion and electrochemical corrosion behaviour of AA2014/Al2O3 nanocomposites fabricated through ultrasonication coupled stir-squeeze casting method

In this work, the tribocorrosion and electrochemical corrosion behaviour of AA2014/Al2O3 (1-4 wt%) nanocomposites were investigated. An unreinforced 2014 alloy and the proposed nanocomposites were prepared through ultrasonication coupled stir-squeeze casting method followed by solutionizing at 510 degrees C for 2 h and ageing at 165 degrees C for 16 h. Studies on the dispersion of nanoparticles, intermetallic phase formation, porosity, and hardness were carried out prior to the corrosion analysis. Tribocorrosion test was performed in a linear reciprocating tribometer using 3.5 wt% NaCl solution as electrolyte under potentiodynamic polarization condition for an exposure period of 600, 900, 1200, and 1500 s. A similar testing condition was applied while performing the electrochemical test of materials in a cylindrical beaker. The experimental results indicated a uniform distribution of nanoparticles and the formation of beta-CuAl2 phase in the nanocomposites. A maximum hardness of 150 HV was obtained for the nanocomposite reinforced with 2 wt% of Al2O3. Tribocorrosion test results indicated that AA2014/3 wt% Al2O3 nanocomposite exhibit the lowest potential of - 0.62 to - 0.68 V with a friction coefficient of 0.15 mu and a minimum current density of 4.889 x 10(-4) at 900 s. The same nanocomposite reduced the removal of metal ions with the lowest potential range of - 0.4 to - 0.5 V and decreased current density of 1.521 x 10(-5) at 1200 s. during the electrochemical test. Alumina hydroxide films and secondary phases caused a superior corrosion resistance at higher exposure times. The microstructural analysis of the corroded surfaces showed pitting corrosion, formation of pits and cracks.

Automated summary

The tribocorrosion and electrochemical corrosion behavior of AA2014/Al2O3 nanocomposites were investigated. The experimental results showed that the nanocomposites with uniform distribution of nanoparticles and the formation of beta-CuAl2 phase exhibited improved hardness, friction coefficient, and corrosion resistance. Alumina hydroxide films and secondary phases contributed to the superior corrosion resistance at longer exposure times.