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Licensed Unlicensed Requires Authentication Published by De Gruyter December 29, 2021

Influence of Ageing on Corrosion Behaviour of Al–Mg–Si Alloys in Chloride and Acid Media

Ananta Kumar Bhattamishra and Kishori Lal

Abstract

This paper deals with studies on corrosion behaviour of two Al–Mg–Si alloys containing excess Si in 1(N) NaCl and 0.1 (N) inorganic acids. Intergranular corrosion and immersion tests were carried out as per standards (MIL-H-6088F, ASTM G-31). Intergranular corrosion was assessed using optical, scanning and transmission electron microscopy. The effects of isothermal and isochronal ageing on corrosion resistance in 0.1(N) HCl and on hardness changes were studied. The studies showed that the amount of intergranular attack in NaCl solution increases with ageing time and is maximum at peak aged condition. Segregation of Si particles and Mg2Si at the grain boundary contributes to intergranular corrosion. Corrosion rate was higher in HCl than in HNO3 and H2SO4 solutions, however it was maximum in 0.1 (N) HCl during its peak aged period.


A. K. Bhattamishra and K. Lal National Metallurgical Laboratory Jamshedpur – 831007 India

  1. The authors wish to record their thanks to Prof. P. Ramachandra Rao, Director, National Metallurgical Laboratory, Jamshedpur for his kind permission to publish this paper.

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Received: 1998-06-12
Published Online: 2021-12-29

© 1998 Carl Hanser Verlag, München