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<p>In the coupled application of aluminum and titanium alloys in marine engineering structures, galvanic corrosion occurs due to the presence of a potential difference. This results in local degradation of the material’s mechanical properties, potentially leading to instability in the engineering structures. This study focuses on the galvanic corrosion behavior and the degradation of mechanical properties of 7075 aluminum alloy when coupled with TA2 pure titanium and TC4 titanium alloy in seawater. A 3.5 wt.% NaCl solution was used to simulate seawater conditions, and immersion tests were conducted at 0, 72, 216, 288, 432, and 720&#xa0;h to investigate the self-corrosion of 7075 aluminum alloy and the galvanic corrosion behavior of the 7075/TA2 and 7075/TC4 couples. A combination of gravimetric analysis, uniaxial tensile tests, and microscopic morphological observations was employed to perform a comparative analysis of the mass loss, mechanical properties, and microstructural changes of 7075 aluminum alloy after immersion. The results reveal that the 7075 aluminum alloy exhibits poor self-corrosion resistance, and the potential difference significantly accelerates its corrosion when acting as the anode. After 720 h of immersion, the self-corrosion mass loss rate of 7075 aluminum alloy was 0.54%, while the mass loss rates for the 7075/TA2 and 7075/TC4 couples were 5.12 and 5.67%, respectively. Importantly, the mechanical properties of 7075 aluminum alloy showed the most significant degradation when coupled with TC4, exhibiting a 13.97% reduction in tensile strength and a 38.70% decrease in elongation after 720 h of immersion. SEM cross-sectional analysis revealed that the maximum corrosion depth reached 32.07&#xa0;μm. In light of the effects of galvanic corrosion, the stress–strain model of 7075 aluminum alloy was modified, yielding a higher degree of agreement with experimental data. This modification provides a valuable reference for evaluating the service life of 7075 aluminum alloy in marine environments.</p>

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Study on the Galvanic Corrosion Behaviors and the Mechanical Properties of 7075 Aluminum Alloy in Simulated Seawater Environment

  • 期刊论文

  • 发表日期：

    2026年7月3日

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  • Wei-Guo Zhou,
  • Wen-Jiao Dan,
  • Le-Le Qi,
  • Xu-Yang Wang

摘要

In the coupled application of aluminum and titanium alloys in marine engineering structures, galvanic corrosion occurs due to the presence of a potential difference. This results in local degradation of the material’s mechanical properties, potentially leading to instability in the engineering structures. This study focuses on the galvanic corrosion behavior and the degradation of mechanical properties of 7075 aluminum alloy when coupled with TA2 pure titanium and TC4 titanium alloy in seawater. A 3.5 wt.% NaCl solution was used to simulate seawater conditions, and immersion tests were conducted at 0, 72, 216, 288, 432, and 720 h to investigate the self-corrosion of 7075 aluminum alloy and the galvanic corrosion behavior of the 7075/TA2 and 7075/TC4 couples. A combination of gravimetric analysis, uniaxial tensile tests, and microscopic morphological observations was employed to perform a comparative analysis of the mass loss, mechanical properties, and microstructural changes of 7075 aluminum alloy after immersion. The results reveal that the 7075 aluminum alloy exhibits poor self-corrosion resistance, and the potential difference significantly accelerates its corrosion when acting as the anode. After 720 h of immersion, the self-corrosion mass loss rate of 7075 aluminum alloy was 0.54%, while the mass loss rates for the 7075/TA2 and 7075/TC4 couples were 5.12 and 5.67%, respectively. Importantly, the mechanical properties of 7075 aluminum alloy showed the most significant degradation when coupled with TC4, exhibiting a 13.97% reduction in tensile strength and a 38.70% decrease in elongation after 720 h of immersion. SEM cross-sectional analysis revealed that the maximum corrosion depth reached 32.07 μm. In light of the effects of galvanic corrosion, the stress–strain model of 7075 aluminum alloy was modified, yielding a higher degree of agreement with experimental data. This modification provides a valuable reference for evaluating the service life of 7075 aluminum alloy in marine environments.