Corrosion stress relaxation and tensile strength effects in an extruded AZ31 magnesium alloy

• Corrosion-stress relaxation on AZ31 shows a reduction in static stress over time.
• General corrosion damage was greater in the immersion environment.
• The continuous presence of water affected the general corrosion and pit formation.
• Tensile test highlight the environmental effects on the strength of the AZ31 alloy.
• Evidence of hydrogen embrittlement and pitting induced failure were observed.

The corrosion effects on the tensile and stress relaxation behavior of an extruded AZ31 magnesium alloy subjected to immersion and salt-spray environments have been investigated. Specimens were simultaneously corroded and stress relaxed in a 3.5 wt.% NaCl solution and then put under a tensile test to failure to determine the stress–strain response over a 60 h test matrix. The AZ31 magnesium alloy shows an evident relaxation in 3.5 wt.% NaCl at room temperature. According to optical and scanning electron microscopy investigations, the fracture surfaces for the immersion environment show a high sensitivity to stress corrosion cracking.