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<p>Laser Powder Bed Fusion (LPBF) of Ni-based superalloys encounters certain challenges in attaining a desirable strength-ductility balance due to the rapid cooling and non-equilibrium solidification associated with the process. In this study, 1&#xa0;wt.% nano-sized Y<sub>2</sub>O<sub>3</sub> particles were incorporated into GH4169 alloy as a strategy to enhance laser absorptivity and regulate the solidification behavior. The effects of this addition on laser absorption, multiscale microstructural evolution, and mechanical performance during LPBF were systematically investigated. The addition of 1&#xa0;wt.% nano-Y<sub>2</sub>O<sub>3</sub> significantly increased laser energy absorptivity (&gt; 0.8), effectively expanding the laser-powder interaction zone and promoting more efficient energy coupling. This improvement in absorptivity directly contributed to a reduction in the melt pool aspect ratio from 0.27 to 0.18, enabling more stable melt dynamics and refined solidification morphology. The enhanced laser-material interaction also facilitated the formation of a uniform microstructure, while the dispersed Y<sub>2</sub>O<sub>3</sub> particles promoted dislocation accumulation and served as effective pinning centers, thereby improving mechanical performance. Compared to the GH4169 alloy, the Y<sub>2</sub>O<sub>3</sub>-modified composite exhibited a 20.1% increase in yield strength and a 19.4% improvement in ultimate tensile strength, while maintaining an elongation above 20%. A quantitative analysis of the strengthening mechanisms revealed that Orowan looping and dislocation strengthening were the dominant contributors, accounting for 72.1% and 35.3% of the total strength increment, respectively. These findings provide mechanistic insights into energy-matter interactions and multiscale strengthening in LPBF, offering a theoretical foundation for integrated composition and process design in next-generation Ni-based superalloys for demanding engineering applications.</p>

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Unveiling the Y2O3-induced laser absorptivity modulation and strength-ductility trade-off mechanism in LPBF-fabricated GH4169 alloy

  • 期刊论文

  • 发表日期：

    2025年11月8日

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  • Huiping Liu,
  • Dongdong Gu,
  • Yanze Li,
  • Jie Wang,
  • Jingjia Sun,
  • Xin Liu,
  • Menghuan Yin,
  • Qi Wu,
  • Wenxin Chen,
  • Yusheng Chen

摘要

Laser Powder Bed Fusion (LPBF) of Ni-based superalloys encounters certain challenges in attaining a desirable strength-ductility balance due to the rapid cooling and non-equilibrium solidification associated with the process. In this study, 1 wt.% nano-sized Y2O3 particles were incorporated into GH4169 alloy as a strategy to enhance laser absorptivity and regulate the solidification behavior. The effects of this addition on laser absorption, multiscale microstructural evolution, and mechanical performance during LPBF were systematically investigated. The addition of 1 wt.% nano-Y2O3 significantly increased laser energy absorptivity (> 0.8), effectively expanding the laser-powder interaction zone and promoting more efficient energy coupling. This improvement in absorptivity directly contributed to a reduction in the melt pool aspect ratio from 0.27 to 0.18, enabling more stable melt dynamics and refined solidification morphology. The enhanced laser-material interaction also facilitated the formation of a uniform microstructure, while the dispersed Y2O3 particles promoted dislocation accumulation and served as effective pinning centers, thereby improving mechanical performance. Compared to the GH4169 alloy, the Y2O3-modified composite exhibited a 20.1% increase in yield strength and a 19.4% improvement in ultimate tensile strength, while maintaining an elongation above 20%. A quantitative analysis of the strengthening mechanisms revealed that Orowan looping and dislocation strengthening were the dominant contributors, accounting for 72.1% and 35.3% of the total strength increment, respectively. These findings provide mechanistic insights into energy-matter interactions and multiscale strengthening in LPBF, offering a theoretical foundation for integrated composition and process design in next-generation Ni-based superalloys for demanding engineering applications.