Effect of crystal orientation and {10(1)over-bar2} twins on the corrosion behaviour of AZ31 magnesium alloy

Pre-compression was conducted on AZ31 magnesium alloy bars to prepare different volume fraction of {10 (1) over bar2} twins. The effect of twins and related crystal orientation on the corrosion properties of the AZ31 magnesium alloy was studied. With the increase of compression strain which induce more twins, corrosion resistance showed different tendency during the immersion tests and potentiodynamic polarization measurements. The original bar showed poor corrosion resistance on the ED-TD plane in immersion tests due to the micro-galvanic corrosion between the (0002) plane and other planes. The corrosion resistance became better with the increase of compression strain due to the decrease of (0002) planes. In contrast, during the potentiodynamic polarization measurements, the original bar showed the best corrosion resistance on the ED-TD plane due to the high proportion of (0002) planes. The corrosion resistance tended to be worse after compression due to the decrease in (0002) planes. (C) 2020 Elsevier B.V. All rights reserved.