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<p>Wire-arc directed energy deposition (DED) is employed to deposit two Ti-6Al-4V blocks using two distinct deposition sequences within an Argon chamber: a unidirectional deposition pattern and a cross-hatch pattern. The trapezoidal-parallelogram overlapping (TPO) model is utilized for in situ measurement of the offset distance, eliminating the need for detailed track profile information. The traditional offset distance of 0.667<i>w</i>, based on the flat top overlapping model, proves unsuitable for various track profiles. Thermo-mechanical modeling is conducted with track profiles categorized as rectangular, trapezoidal-parallelogram, and according to the actual track profile (non-linear) for both sequences. The trapezoidal-parallelogram and non-linear profile demonstrate alignment with experimental residual stress data. Although the rectangular profile provides a reasonable match, it may lack accuracy when significant strain from phase transformation occurs, as it minimizes or omits the overlapping reheating effect essential for precise stress and strain predictions. The cross-hatch pattern significantly reduces longitudinal residual stress values compared to the unidirectional deposition pattern. The substrate shows higher residual stress magnitudes of 354.3 ± 12.5&#xa0;MPa at the bottom and − 859.7 ± 40.4&#xa0;MPa at the top for the unidirectional pattern. In contrast, the cross-hatch pattern displays comparatively lower stress magnitudes, with tensile and compressive stresses of 313.2 ± 7.2&#xa0;MPa and − 770.4 ± 48.5&#xa0;MPa, respectively. Irrespective of the deposition sequence, higher tensile stresses are observed in the tracks deposited at last while existing tracks show lower tensile stresses due to the&#xa0;reheating effect. Due to the bowing distortion, compressive stresses are observed on the top of the substrate, while tensile stresses are observed&#xa0;on the bottom.</p>

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Thermal–mechanical analysis of Ti-6Al-4V components in wire-arc directed energy deposition using a novel in situ trapezoidal-parallelogram overlapping (TPO) model

  • 期刊论文

  • 发表日期：

    2025年2月4日

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  • Sudheer Kumar Polamuri,
  • Avinash Mishra,
  • Srihari Chitral,
  • Venkata Kiran Degala,
  • Ajay Kumar

摘要

Wire-arc directed energy deposition (DED) is employed to deposit two Ti-6Al-4V blocks using two distinct deposition sequences within an Argon chamber: a unidirectional deposition pattern and a cross-hatch pattern. The trapezoidal-parallelogram overlapping (TPO) model is utilized for in situ measurement of the offset distance, eliminating the need for detailed track profile information. The traditional offset distance of 0.667w, based on the flat top overlapping model, proves unsuitable for various track profiles. Thermo-mechanical modeling is conducted with track profiles categorized as rectangular, trapezoidal-parallelogram, and according to the actual track profile (non-linear) for both sequences. The trapezoidal-parallelogram and non-linear profile demonstrate alignment with experimental residual stress data. Although the rectangular profile provides a reasonable match, it may lack accuracy when significant strain from phase transformation occurs, as it minimizes or omits the overlapping reheating effect essential for precise stress and strain predictions. The cross-hatch pattern significantly reduces longitudinal residual stress values compared to the unidirectional deposition pattern. The substrate shows higher residual stress magnitudes of 354.3 ± 12.5 MPa at the bottom and − 859.7 ± 40.4 MPa at the top for the unidirectional pattern. In contrast, the cross-hatch pattern displays comparatively lower stress magnitudes, with tensile and compressive stresses of 313.2 ± 7.2 MPa and − 770.4 ± 48.5 MPa, respectively. Irrespective of the deposition sequence, higher tensile stresses are observed in the tracks deposited at last while existing tracks show lower tensile stresses due to the reheating effect. Due to the bowing distortion, compressive stresses are observed on the top of the substrate, while tensile stresses are observed on the bottom.