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<p>Titanium parts fabricated by laser powder bed fusion (LPBF) offer advantages such as high material utilization and fewer production steps, making them increasingly popular in aero-engine fuel systems. However, significant scale discrepancies between the as-built part size and particle size challenge in controlling the high-speed melting process, leading to defects like porosity. This study applied a CFD-DEM model to predict the impact of powder spreading speed on the morphology of the powder bed during the spreading process and its subsequent influence on porosity in Ti-6Al-4V cladding layers. Numerical simulations reveal the influence of operating parameters on pore formation in printed parts, with experimental verification supporting these findings. The results demonstrate that the powder spreading speed has a substantial effect on the powder bed morphology. Accelerating the paving speed leads to surface roughness, improved fluidity of large particles, and increased probabilities of scraper impacts and powder splashing. Lower bulk density was observed at a faster paving speed, which in turn impacts porosity. Low bulk density results in a smooth cladding layer, while high bulk density leads to protrusions in the cladding layer. Higher bulk densities increase heat absorption efficiency and molten pool size. The minimum porosity was observed at a bulk density of approximately 0.375, corresponding to a powder paving speed of 75 mm/s. Characterization and tensile tests confirmed that the laying speed can effectively reduce the porosity and improve the mechanical properties (5.73% yield strain and 15.24% yield stress higher than bulk density of 0.332). This work offers valuable insights for controlling porosity in LPBF processes.</p>

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Influence Paving Speed on Porosity Reduction in Ti-6Al-4V Alloy Through Process Simulation in LPBF

  • 期刊论文

  • 发表日期：

    2026年3月14日

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  • Meng Chen,
  • Hongyu Yu,
  • Miao Liu,
  • Qi Zhang,
  • Fan Wang,
  • Zheng Liu,
  • Wenwei Zhang,
  • Mei Li,
  • Zhongqiu Liu

摘要

Titanium parts fabricated by laser powder bed fusion (LPBF) offer advantages such as high material utilization and fewer production steps, making them increasingly popular in aero-engine fuel systems. However, significant scale discrepancies between the as-built part size and particle size challenge in controlling the high-speed melting process, leading to defects like porosity. This study applied a CFD-DEM model to predict the impact of powder spreading speed on the morphology of the powder bed during the spreading process and its subsequent influence on porosity in Ti-6Al-4V cladding layers. Numerical simulations reveal the influence of operating parameters on pore formation in printed parts, with experimental verification supporting these findings. The results demonstrate that the powder spreading speed has a substantial effect on the powder bed morphology. Accelerating the paving speed leads to surface roughness, improved fluidity of large particles, and increased probabilities of scraper impacts and powder splashing. Lower bulk density was observed at a faster paving speed, which in turn impacts porosity. Low bulk density results in a smooth cladding layer, while high bulk density leads to protrusions in the cladding layer. Higher bulk densities increase heat absorption efficiency and molten pool size. The minimum porosity was observed at a bulk density of approximately 0.375, corresponding to a powder paving speed of 75 mm/s. Characterization and tensile tests confirmed that the laying speed can effectively reduce the porosity and improve the mechanical properties (5.73% yield strain and 15.24% yield stress higher than bulk density of 0.332). This work offers valuable insights for controlling porosity in LPBF processes.