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    Rights statement: This is the author’s version of a work that was accepted for publication in Journal of Manufacturing Processes. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Manufacturing Processes, 58, 2020 DOI: 10.1016/j.jmapro.2020.09.026

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Effect of beam defocusing on porosity formation in laser-MIG hybrid welded TA2 titanium alloy joints

Research output: Contribution to journalJournal articlepeer-review

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  • S. Chen
  • S. Luo
  • H. Yu
  • H. Geng
  • G. Xu
  • R. Li
  • Y. Tian
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<mark>Journal publication date</mark>1/10/2020
<mark>Journal</mark>Journal of Manufacturing Processes
Volume58
Number of pages11
Pages (from-to)1221-1231
Publication StatusPublished
Early online date21/09/20
<mark>Original language</mark>English

Abstract

The influence of defocusing distance on porosity formation during laser-MIG hybrid welding of TA2 titanium alloy joints was studied by both experimental and numerical methods. The experimental results showed that the population of porosities decreased in the welded joint when the defocusing distance increased from +6 mm to +12 mm, while other welding parameters remained unchanged. A volume of fluid (VOF) model was built in FLUENT by coupling the laser induced keyhole, MIG droplet and melt pool. The simulation results suggested the formation of porosities can be attributed to the collapse of the keyhole that can trap the open space at its bottom, thanks to the vigorous laser-material interaction. When the defocusing distance increases, the laser energy density drops and the keyhole becomes shallower leading to a weaker liquid metal vortex flow. In this case, the open space at the bottom of the keyhole could be backfilled with the surrounding liquid metal when the keyhole collapse, resulting in less porosity in the solidified weld.

Bibliographic note

This is the author’s version of a work that was accepted for publication in Journal of Manufacturing Processes. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Manufacturing Processes, 58, 2020 DOI: 10.1016/j.jmapro.2020.09.026