在铝合金激光搭接焊中，镁元素烧损将大大降低焊缝的抗拉强度。为了消除铝合金激光搭接焊中镁元素的烧损对焊接接头的负面影响，采用在铝合金激光焊接接头中填加镁粉的方法，研究焊接速率对镁元素烧损的影响。实验中，测量了焊缝中镁元素在垂直和水平方向的分布，并对焊接接头抗拉强度进行了测试；分析了焊接接头中镁含量和抗拉强度之间的关系，比较了填镁量不同时各焊接接头的抗拉强度。结果表明，镁元素的烧损极大地影响了焊缝的抗拉强度，在激光焊接中填镁能有效地提高焊缝的抗拉强度；相比没填镁，填镁的焊接接头抗拉强度最大改善可以达到36.06％；当焊缝中镁元素的质量分数大约是0.026时，抗拉强度强度达到最大值。这为改善铝合金激光焊接接头强度提供了新的理论依据和方法。%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 .
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