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<p>Joining dissimilar AA2060-T8 and AA2099-T83 alloys using conventional arc welding is challenging due to the presence of high heat input, complex thermal cycles, solidification cracks, coarse grain structures, and dissolution of precipitates. To overcome these limitations, the present study utilized gas tungsten arc welding (GTAW) in pulsed current mode with the aim of establishing process–microstructure–property correlations and identifying optimum welding factors. The influence of pulse frequency, pulse time ratio, and shielding gas flow rate on average grain diameter (AGD), microhardness, and wear rate was studied through the response surface method (RSM). Analysis of variance (ANOVA) results showed that the pulse frequency had the most significant impact, followed by the pulse time ratio, while the gas flow rate had the least effect. Electron backscatter diffraction (EBSD) results showed the pulsed GTAW mode yielded a significant grain boundary (GB) transformation around 70.05% with a maximum texture intensity value of 9.307. Transmission electron microscopy (TEM) results revealed <i>α</i>-Al, <i>θ</i>΄ (Al<sub>2</sub>Cu), <i>δ</i>΄ (Al<sub>3</sub>Li), T1 (Al<sub>2</sub>CuLi), and T<sub>2</sub> (Al<sub>6</sub>CuLi<sub>3</sub>) precipitate phases across the weld FZ region. Multi-response optimization using the RSM-desirability function yielded optimal parameters:&#xa0;pulse frequency = 9.294&#xa0;Hz, pulse time ratio = 1:2, and gas flow rate = 8.502&#xa0;l/min, which yielded an AGD of 13.28&#xa0;μm, a microhardness of 94.15 HV, and a wear rate of 0.587 × 10<sup>−3</sup>&#xa0;mm<sup>3</sup>/Nm. The pulsed GTAW method resulted in significant grain refinement, uniform precipitate dispersion, increased GB transformations, and texture strengthening, demonstrating RSM-driven optimization in enhancing process efficiency and producing quality joints.</p>

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Empirical Correlations and Optimization of Pulsed GTAW Parameters in Dissimilar AA2060-T8 and AA2099-T83 Alloys Using RSM: Microstructure Evolution and Tribological  Performance

  • 期刊论文

  • 发表日期：

    2026年4月6日

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  • Md Saquib Bin Reyaz,
  • Vikas Misra,
  • Md Parwez Alam,
  • Sunny Chandra,
  • Shiv Kumar Ray

摘要

Joining dissimilar AA2060-T8 and AA2099-T83 alloys using conventional arc welding is challenging due to the presence of high heat input, complex thermal cycles, solidification cracks, coarse grain structures, and dissolution of precipitates. To overcome these limitations, the present study utilized gas tungsten arc welding (GTAW) in pulsed current mode with the aim of establishing process–microstructure–property correlations and identifying optimum welding factors. The influence of pulse frequency, pulse time ratio, and shielding gas flow rate on average grain diameter (AGD), microhardness, and wear rate was studied through the response surface method (RSM). Analysis of variance (ANOVA) results showed that the pulse frequency had the most significant impact, followed by the pulse time ratio, while the gas flow rate had the least effect. Electron backscatter diffraction (EBSD) results showed the pulsed GTAW mode yielded a significant grain boundary (GB) transformation around 70.05% with a maximum texture intensity value of 9.307. Transmission electron microscopy (TEM) results revealed α-Al, θ΄ (Al2Cu), δ΄ (Al3Li), T1 (Al2CuLi), and T2 (Al6CuLi3) precipitate phases across the weld FZ region. Multi-response optimization using the RSM-desirability function yielded optimal parameters: pulse frequency = 9.294 Hz, pulse time ratio = 1:2, and gas flow rate = 8.502 l/min, which yielded an AGD of 13.28 μm, a microhardness of 94.15 HV, and a wear rate of 0.587 × 10−3 mm3/Nm. The pulsed GTAW method resulted in significant grain refinement, uniform precipitate dispersion, increased GB transformations, and texture strengthening, demonstrating RSM-driven optimization in enhancing process efficiency and producing quality joints.