Texture-governed electrochemical behaviour of cross rolled Mg-5Al-5Sn (AT55) magnesium alloy

Abstract

Texture dependence electrochemical attributes of cross rolled Mg–5Al–5Sn (AT55) alloy is presented in this work. AT55 magnesium alloy was cross-rolled at three different temperatures (350 °C,400 °C and 450 °C) with 60% reduction in thickness. The resulted grain refinement with desirable texture by cross rolling improves the passive film capability of AT55 alloy. This is attributed by refinement grains and secondary phase during rolling, preferably at (0001) texture orientation. Corrosion result depicts that corrosion resistance of cross rolled specimens is better than that of as-cast condition. The AT55 alloy in all conditions exhibits relatively narrow positive hysteresis and high break down potential when compared to the as received condition. The cross-rolled alloy exhibits lower pitting potential value. Electro-chemical impedence spectroscopy reveals formation of larger capacitive loop at 350 °C rolled condition that results in relatively lower levels of pit formation.