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<p>The current study aims to evaluate the influence of different lap configurations on the corrosion behavior and microhardness characteristics of dissimilar friction stir lap welds (FSLW) of Al alloys (AA5083-H11, AA6061-T6, and AA7075-T6). FSLW involves different nature of intermixing of dissimilar materials across the interface due to variations in alloy properties and placement (top or bottom). To explore these effects, six different lap configurations: T6/B7, T7/B6, T5/B7, T7/B5, T5/B6, and T6/B5 (indicates material placement on top/bottom; T6/B7 ≡ plate at Top is 6061 alloy, bottom is 7075 alloy) are fabricated at a constant tool rotation speed of 1200&#xa0;rpm and traverse speed of 98&#xa0;mm/min. Electrochemical corrosion tests revealed that the AA6061/AA5083 joints exhibited minimum corrosion susceptibility with corrosion rates of 1.31 mpy (T5/B6) and 1.18 mpy (T6/B5), attributed to effective material intermixing and reduced galvanic coupling. Conversely, AA7075/AA5083 joints are more prone to corrosion, showing corrosion rates of 3.56 mpy (T5/B7) and 3.25 mpy (T7/B5) due to strong galvanic interactions and microstructural heterogeneity. Microhardness analysis indicated lower hardness in the HAZ/TMAZ than in the SZ due to over-aging and precipitate coarsening. Intense intergranular and exfoliation corrosion occur in AA7075 in the weld zone likely driven by the grain boundary η phase (MgZn<sub>2</sub>), while AA6061 is observed more prone to pitting that initiates at Mg<sub>2</sub>Si precipitates.</p>

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Electrochemical Corrosion Analysis of Friction Stir Lap Welding of Dissimilar AA5083, AA6061, and AA7075 Alloys at Different Configurations

  • 期刊论文

  • 发表日期：

    2025年11月25日

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  • Nikhil Kumar,
  • Anirban Bhattacharya,
  • Saurav Keshri,
  • Anup Kumar Keshri

摘要

The current study aims to evaluate the influence of different lap configurations on the corrosion behavior and microhardness characteristics of dissimilar friction stir lap welds (FSLW) of Al alloys (AA5083-H11, AA6061-T6, and AA7075-T6). FSLW involves different nature of intermixing of dissimilar materials across the interface due to variations in alloy properties and placement (top or bottom). To explore these effects, six different lap configurations: T6/B7, T7/B6, T5/B7, T7/B5, T5/B6, and T6/B5 (indicates material placement on top/bottom; T6/B7 ≡ plate at Top is 6061 alloy, bottom is 7075 alloy) are fabricated at a constant tool rotation speed of 1200 rpm and traverse speed of 98 mm/min. Electrochemical corrosion tests revealed that the AA6061/AA5083 joints exhibited minimum corrosion susceptibility with corrosion rates of 1.31 mpy (T5/B6) and 1.18 mpy (T6/B5), attributed to effective material intermixing and reduced galvanic coupling. Conversely, AA7075/AA5083 joints are more prone to corrosion, showing corrosion rates of 3.56 mpy (T5/B7) and 3.25 mpy (T7/B5) due to strong galvanic interactions and microstructural heterogeneity. Microhardness analysis indicated lower hardness in the HAZ/TMAZ than in the SZ due to over-aging and precipitate coarsening. Intense intergranular and exfoliation corrosion occur in AA7075 in the weld zone likely driven by the grain boundary η phase (MgZn2), while AA6061 is observed more prone to pitting that initiates at Mg2Si precipitates.