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<p>Porosity is a serious concern in components fabricated through the wire arc additive manufacturing (WAAM) process, including those out of aluminum alloys. Also, defects like hump and crater contribute to post-processing material losses. This study investigates strategies to mitigate defects in WAAM-fabricated components, by maneuvering heat input and gas flow rate. The results demonstrate that the hump defect, attributed to molten metal backflow from welding torch momentum changes, is effectively eliminated using pulse with weaving mode, whereas the crater defects are minimized in pulse and pulse with weaving modes due to lower heat inputs. While continuous mode shows no visible porosity, pulse and pulse with weaving modes exhibit pore counts of 100 and 210, respectively. Simulations reveal that each newly deposited layer completely remelts the preceding two layers, facilitating hydrogen gas escape and interdendritic void filling. Furthermore, increasing the gas flow rate from 5 to 25&#xa0;l/min reduces pore count by 70%, which is attributed to enhanced shielding that minimizes surrounding gas and moisture ingress. These insights provide a basis for optimizing WAAM processes to reduce defect formation and improve component integrity.</p>

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Mitigation of Porosity and Surface Defects in Wire Arc Additive Manufactured Aluminium Alloy through Heat Input and Inert Gas Flow Control

  • 期刊论文

  • 发表日期：

    2025年6月10日

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  • Kumar Ujjwal,
  • Chanchal Chauhan,
  • R. K. Singh Raman,
  • Alok Kumar Das

摘要

Porosity is a serious concern in components fabricated through the wire arc additive manufacturing (WAAM) process, including those out of aluminum alloys. Also, defects like hump and crater contribute to post-processing material losses. This study investigates strategies to mitigate defects in WAAM-fabricated components, by maneuvering heat input and gas flow rate. The results demonstrate that the hump defect, attributed to molten metal backflow from welding torch momentum changes, is effectively eliminated using pulse with weaving mode, whereas the crater defects are minimized in pulse and pulse with weaving modes due to lower heat inputs. While continuous mode shows no visible porosity, pulse and pulse with weaving modes exhibit pore counts of 100 and 210, respectively. Simulations reveal that each newly deposited layer completely remelts the preceding two layers, facilitating hydrogen gas escape and interdendritic void filling. Furthermore, increasing the gas flow rate from 5 to 25 l/min reduces pore count by 70%, which is attributed to enhanced shielding that minimizes surrounding gas and moisture ingress. These insights provide a basis for optimizing WAAM processes to reduce defect formation and improve component integrity.