Environment-assisted cracking of AZ31 magnesium alloy in a borate buffer solution containing ammonium thiocyanate under various potentials

The environment-assisted cracking behavior of AZ31 magnesium alloy was investigated using tensile tests at cathodic and corrosion potentials in a Na ₂B ₄O ₇∙10H ₂O solution containing NH ₄ SCN and in air. Although the mechanical properties of the AZ31 with an initial strain rate of 10 ⁻⁴ s ⁻¹ were independent of the environments, those degraded in the solution with an initial strain rate of 10 ⁻⁶ s ⁻¹ . The total elongation became smaller at higher potentials. The average hydrogen absorption rate increased with a positive potential shift. These facts imply that environment-assisted cracking became more severe under relatively high potential owing to corrosion accompanied by enhanced hydrogen absorption.