Experimental Investigations on Corrosion Behaviour of Cast Al-Mg Alloys

Author : G. Swami Naidua

Abstract

5XXX series alloys provide excellent resistance to all forms of corrosion. This accounts for their common use in a variety of applications requiring good corrosion resistance, including building products, chemical processing, and food handling. For a fixed amount of cold work, the mass loss due to corrosion in cast Al-Mg alloys is determined as a function of concentration of magnesium. The mass loss is decreased with increase in magnesium concentration of the alloy. The high-magnesium alloys have greater strength than the low-magnesium alloys, and hence they possess outstanding corrosion resistance. Keeping the magnesium concentration constant, the deformation is varied and the mass loss due to corrosion is determined. With increase in deformation, the mass loss due to corrosion is decreased. In Al-Mg alloys strength is developed mainly through work hardening and to a lesser extent by grain size effects. With increase in plastic deformation, the grain size becomes finer and hence the strength and hardness. The corrosion resistance of the alloy subjected to different heat treatments are also studied.

Keywords: Corrosion, deformation, composition, ageing