Study on the reason of porosity formation in laser welding of magnesium and aluminum dissimilar metal

TIAN Wei; ZHOU Dian-wu; QIAO Xiao-jie; LI Sheng

doi:10.7510/jgjs.issn.1001-3806.2013.06.027

In order to study the reason of porosity formation in laser welding of magnesium and aluminum dissimilar metal, AZ91 magnesium alloy in 1.8mm thick and 6016 aluminum alloy in 1.2mm thick were weld by means of laser lap welding. By using scanning electron microscope(SEM) and comes energy dispersive spectroscopy(EDS), the micro-morphology and element distribution of the average area, the interior region and the surrounding area of the porosity as well as the base material of magnesium and aluminum dissimilar metal weld was studied. The results show that the element evaporation burning, the oxide film remaining on the surface of the base material and the pre-existing micro-pores in the base material are the main sources of porosity in the laser welding of magnesium and aluminum dissimilar metal. Adding material to suppress element evaporated burning, cleaning the oxide film of the upper and lower surfaces of magnesium plates and aluminum plates before welding and eliminating the original hydrogen micro-pores in magnesium plate are the important measures to prevent the porosity formation in the laser welding of magnesium and aluminum dissimilar metal.The study is helpful to obtain low porosity ratio welded joints of Mg/Al and improve the welding quality.

Study on the reason of porosity formation in laser welding of magnesium and aluminum dissimilar metal

Corresponding author: ZHOU Dian-wu, zdwe_mail@yahoo.com.cn;

1. State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China

Received Date: 2013-01-09

Accepted Date: 2013-01-18

Available Online: 2013-11-25

Abstract: In order to study the reason of porosity formation in laser welding of magnesium and aluminum dissimilar metal, AZ91 magnesium alloy in 1.8mm thick and 6016 aluminum alloy in 1.2mm thick were weld by means of laser lap welding. By using scanning electron microscope(SEM) and comes energy dispersive spectroscopy(EDS), the micro-morphology and element distribution of the average area, the interior region and the surrounding area of the porosity as well as the base material of magnesium and aluminum dissimilar metal weld was studied. The results show that the element evaporation burning, the oxide film remaining on the surface of the base material and the pre-existing micro-pores in the base material are the main sources of porosity in the laser welding of magnesium and aluminum dissimilar metal. Adding material to suppress element evaporated burning, cleaning the oxide film of the upper and lower surfaces of magnesium plates and aluminum plates before welding and eliminating the original hydrogen micro-pores in magnesium plate are the important measures to prevent the porosity formation in the laser welding of magnesium and aluminum dissimilar metal.The study is helpful to obtain low porosity ratio welded joints of Mg/Al and improve the welding quality.

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Reference (16)

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Study on the reason of porosity formation in laser welding of magnesium and aluminum dissimilar metal

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