CORROSION CHARACTERISTICS OF AL-0.91MG-0.55SI-1.12FE-0.39CA AL-ALLOY AGED AT ELEVATED TEMPERATURE IN 0.8MH2SO4 SOLUTION

Suresh Chand, Madhusudhan D

Abstract: The study of degradation of Al-0.91Mg-0.55Si-1.12Fe-0.39Ca aluminum-alloy is carried out under different state of microstructure. The reason for this work is to decide the impact of heat treatment on the microstructure and the corrosive consumption of Al-alloy in acid utilizing weight reduction system. Specimens were solution treated at 545 oC and artificially aged at 185 oC. The maximum hardness is found after aging for 12 hrs. They were immersed in 0.8 molar solution of sulfuric acid for 0.58 hrs, 1.08 hrs, 1.58, 2.08 hrs and 2.58 hrs. The corrosion rates were calculated for various immersion periods. The test work has uncovered that time and temperature assumes an imperative part in the precipitation transformation procedure of the Al-ally. The hardness increases due to formation of second phase particles of Mg2Si. In over-aging of the alloy, the growth of the precipitate particle takes place at the expense of smaller precipitate particles. The rate of corrosion is found lower in the artificially aged specimen. The corrosion rates are found stabilized after 2.08 hrs of immersion in H2SO4. The X-Ray Diffraction patterns are also analyzed in the range of 10-80° which are showing peaks of aluminum solid solution and Mg2Si in the different patterns.

Keywords: Corrosion rate, Aluminum alloys, aging of alloy, solutionizing, acid, weight reduction

DOI: https://doi.org/10.15623/ijret.2015.0411042