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<p>Laser powder bed fusion (LPBF) process involves extremely high heating and cooling rates, as well as strong temperature gradients, inevitably inducing thermal and residual stresses in printed parts. These stresses can lead to distortion, solidification cracks and even delamination, severely compromising mechanical performance of builds. The present work investigated the effects of build platform temperature (300&#xa0;K and 478&#xa0;K) on melt pool behavior and thermal stress evolution during a single-track laser scanning of AlSi10Mg powder bed, using coupled Computational Fluid Dynamics (CFD) and Finite Element Model (FEM). First, CFD simulations were performed to obtain spatio-temporal temperature data, which was then imported into finite element models. Subsequently, thermo-mechanical simulations with birth–death element method and temperature-dependent elastic–plastic material properties were conducted to analyze thermal/residual stresses in the track-scale build. It is found that increasing platform temperature leads to an increase of melt pool size and a reduction of temperature gradients. The residual stresses are revealed to be highly inhomogeneous, as the melt pool center presents a dominant stress component in the laser scanning direction, while the melt pool border is subjected to a bi-axial stress state and a stress concentration. Preheating the platform to 478&#xa0;K notably mitigates the stress level, especially at the melt pool border (roughly by 60%). Interestingly, the thermal stresses rise rapidly and differ between the cold and hot platforms only near the end of the cooling stage, in a relatively low temperature range (500&#xa0;K–300&#xa0;K). The findings of the present work might be used to guide process optimization devoted to mitigate thermal and residual stresses.</p>

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Computational insights into effects of build platform temperature on track-scale thermal and residual stresses during laser powder bed fusion process

  • 期刊论文

  • 发表日期：

    2025年10月11日

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  • Lubin Song,
  • Xuehai Qian,
  • Shijie Liu,
  • Lv Zhao,
  • Yaxin Zhu,
  • Shuang Liang,
  • Minsheng Huang,
  • Zhenhuan Li

摘要

Laser powder bed fusion (LPBF) process involves extremely high heating and cooling rates, as well as strong temperature gradients, inevitably inducing thermal and residual stresses in printed parts. These stresses can lead to distortion, solidification cracks and even delamination, severely compromising mechanical performance of builds. The present work investigated the effects of build platform temperature (300 K and 478 K) on melt pool behavior and thermal stress evolution during a single-track laser scanning of AlSi10Mg powder bed, using coupled Computational Fluid Dynamics (CFD) and Finite Element Model (FEM). First, CFD simulations were performed to obtain spatio-temporal temperature data, which was then imported into finite element models. Subsequently, thermo-mechanical simulations with birth–death element method and temperature-dependent elastic–plastic material properties were conducted to analyze thermal/residual stresses in the track-scale build. It is found that increasing platform temperature leads to an increase of melt pool size and a reduction of temperature gradients. The residual stresses are revealed to be highly inhomogeneous, as the melt pool center presents a dominant stress component in the laser scanning direction, while the melt pool border is subjected to a bi-axial stress state and a stress concentration. Preheating the platform to 478 K notably mitigates the stress level, especially at the melt pool border (roughly by 60%). Interestingly, the thermal stresses rise rapidly and differ between the cold and hot platforms only near the end of the cooling stage, in a relatively low temperature range (500 K–300 K). The findings of the present work might be used to guide process optimization devoted to mitigate thermal and residual stresses.