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<p>Wire and Arc Additive Manufacturing (WAAM) has emerged as a promising technique for fabricating large-scale metallic components, but intrinsic microstructural and mechanical heterogeneities along the build height may critically affect their tribological performance. Understanding how these gradients influence friction and wear behavior is essential for optimizing WAAM-processed materials for functional applications. This work assesses the effect of torch kinematics on dry-sliding behavior of ER308LSi walls built with five trajectories. Optical microscopy along with microhardness measurements, revealed a vertical gradient: the δ-ferrite fraction decreased from ~ 6% at the substrate to ~ 4% at the top, accompanied by a hardness decline from 220 HV to 170 HV. Lateral microstructures remained statistically indistinguishable across trajectories, indicating that torch motion did not perturb the dominant thermal regime. Dry sliding tests were performed on specimens extracted from the base, top and side faces under normal loads of 4, 8 and 16&#xa0;N. The volumetric wear coefficient (k) increased nearly linearly with load, whereas the steady-state friction coefficient (µ) decreased from ≈ 0.70 to ≈ 0.45. Neither metric showed a significant dependence on deposition path; instead, sampling position governed performance: basal regions, enriched in δ-ferrite and harder, exhibited the lowest k, while the top layers displayed the highest material loss. Microscopy corroborated a transition from mild micro-abrasion and limited adhesion at 4&#xa0;N to severe ploughing, tribofilm fracture and adhesive pull-out at 16&#xa0;N. The findings demonstrate that interlayer thermal management, specifically stabilizing δ-ferrite between 4% and 6%, is the primary lever for enhancing WAAM stainless-steel wear resistance. Deposition path may thus be selected to optimize productivity or residual-stress distribution without compromising tribological performance, provided adequate cooling is maintained.</p>

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Influence of deposition-path strategy on dry-sliding wear behavior of WAAM-fabricated austenitic stainless steel

  • 期刊论文

  • 发表日期：

    2026年1月5日

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  • Rudimar Luís Becker,
  • Rafael Luciano Dalcin,
  • William Lemos Bevilaqua,
  • Leandro João da Silva,
  • Cristiano José Scheuer

摘要

Wire and Arc Additive Manufacturing (WAAM) has emerged as a promising technique for fabricating large-scale metallic components, but intrinsic microstructural and mechanical heterogeneities along the build height may critically affect their tribological performance. Understanding how these gradients influence friction and wear behavior is essential for optimizing WAAM-processed materials for functional applications. This work assesses the effect of torch kinematics on dry-sliding behavior of ER308LSi walls built with five trajectories. Optical microscopy along with microhardness measurements, revealed a vertical gradient: the δ-ferrite fraction decreased from ~ 6% at the substrate to ~ 4% at the top, accompanied by a hardness decline from 220 HV to 170 HV. Lateral microstructures remained statistically indistinguishable across trajectories, indicating that torch motion did not perturb the dominant thermal regime. Dry sliding tests were performed on specimens extracted from the base, top and side faces under normal loads of 4, 8 and 16 N. The volumetric wear coefficient (k) increased nearly linearly with load, whereas the steady-state friction coefficient (µ) decreased from ≈ 0.70 to ≈ 0.45. Neither metric showed a significant dependence on deposition path; instead, sampling position governed performance: basal regions, enriched in δ-ferrite and harder, exhibited the lowest k, while the top layers displayed the highest material loss. Microscopy corroborated a transition from mild micro-abrasion and limited adhesion at 4 N to severe ploughing, tribofilm fracture and adhesive pull-out at 16 N. The findings demonstrate that interlayer thermal management, specifically stabilizing δ-ferrite between 4% and 6%, is the primary lever for enhancing WAAM stainless-steel wear resistance. Deposition path may thus be selected to optimize productivity or residual-stress distribution without compromising tribological performance, provided adequate cooling is maintained.