Assessing hidden corrosion in AZ91 magnesium alloy via infrared thermography in simulated atmospheric acid rain conditions

Abstract Magnesium alloys have gained significant importance in the aerospace and marine industries due to their favorable mechanical properties, such as low density and high strength-to-weight ratio. However, their susceptibility to corrosion poses a challenge to their widespread use in these applications. Studies have been conducted to investigate the uniform surface corrosion behavior of magnesium alloys, aiming to understand the underlying mechanisms and develop effective corrosion protection strategies. However, studies on hidden corrosion are sparse. Hidden corrosion is a highly perilous defect that poses a significant risk to the structural integrity of aging aircraft. This work explores the hidden corrosion behavior of AZ91 series alloy using infrared thermographic non-destructive testing. This study employed the AZ91 magnesium alloy, where seven blind holes were drilled on its surface, and the alloy was then exposed to simulated acid rain for ten days to examine corrosion effects using infrared thermography. The hole dimensions and rate of corrosion were determined.