焊接电流对涂覆TiO2活性剂AZ31镁合金TIG焊的影响（英文）

研究焊接电流对涂覆TiO2活性剂AZ31镁合金板材活性钨极氩弧焊(A-TIG)焊接接头的宏观形貌、微观结构和力学性能的影响。实验结果表明,随着焊接电流的增加,焊缝的熔深和熔宽比增加,涂覆TiO2的焊缝表面形貌逐渐恶化;焊缝中α-Mg晶粒尺寸增加,颗粒状β-Mg17Al12数量增多。与普通的TIG焊相比,A-TIG焊缝熔深明显增加并且晶粒尺寸粗化。当焊接电流小于130 A时,涂覆TiO2焊接接头的极限抗拉强度值随着焊接电流的增加而增加,当焊接电流超过130 A时其抗拉强度值开始下降;焊缝热影响区和熔合区的平均显微硬度随着焊接电流的增加逐渐降低。

Effects of welding current on properties of A-TIG welded AZ31 magnesium alloy joints with TiO2 coating

The effects of welding current on the macro-morphology, microstructure and mechanical properties of tungsten inert gas (TIG) welded AZ31 magnesium alloy joints with TiO₂ coating were investigated. The results showed that the increase of welding current led to the increase in the depth/width ratio and deteriorated the surface appearance of the welded seams with TiO₂ coating. The grain size of α-Mg and the amount of granular β-Mg₁₇Al₁₂ particles in the welded seams also increased. The welded joints with TiO₂ coating exhibited a deeper weld penetration and larger grain size compared with the welded joint without TiO₂ coating. When the welding current was less than 130 A, the ultimate tensile strength of the welded joints with TiO₂ coating increased with the increase in welding current and then decreased when the welding current was greater than 130 A. The average microhardness of the heat-affected zone and fusion zone decreased gradually with the increase of welding current.