Combined effect of composition and surface condition on corrosion behaviour of magnesium alloys AZ31 and AZ61

The work is an attempt to learn more about the role of several experimental variables in the corrosion of magnesium alloys in immersion tests carried out in 0.6 M NaCl. The effect of as-received and polished surface conditions, geometrical characteristics of the exposed area and different aluminium contents in the magnesium based alloys is considered. Results indicated that polished surfaces and AZ61 surfaces tend to develop corrosion slower than the respective as-received and AZ31 surfaces; these tendencies can change by prolonging exposure time. Filiform and localised corrosion are influenced by the presence of cut surfaces and small exposed areas, respectively.

► Effect of test variables on the corrosion behavior of AZ31 and AZ61 alloys.
► Polished surfaces developed corrosion slower than as-received surfaces.
► High susceptibility to filiform corrosion in regions close to the shear cut edges.
► Test time influence on the corrosion rate of AZ61 alloy.