Study on improving mechanical properties of the welds by filling magnesium powder during laser welding 5052 aluminum alloy

Magnesium is an important strengthening alloying element in aluminum alloy, the burning loss of which will greatly reduce such mechanical property of the welds as the tensile strength during laser lap welding of aluminum alloy. In order to eliminate the negative effect of the burning loss of magnesium on mechanical property of the welds, filling magnesium powder is adopted filled in laser welding aluminum alloy. The contents of magnesium in the welds were measured both in the vertical and horizontal directions, and the effect of welding velocity on the burning loss of magnesium was experimentally studied. Then, the tensile strength of the welds was tested. Compared after comparing the tensile strength of the welds under different magnesium contents, the relationship between the content of magnesium element of the welds and tensile strength was studied. The results show that the reduction of magnesium content due to the burning loss of magnesium can greatly affect the tensile strength of the welds, filling magnesium during laser welding can effectively improve the tensile strength of the welds, the maximum of the improvement can reach to 36.06% compared to those without filling magnesium. When the mass fraction of the magnesium element in the welds is about 0.026,the tensile strength of the welds reaches the maximum. This study provides new theoretical basis and methods to improve the strength of aluminum alloy laser welded joints.