Here, ultrasonic–wave–assisted gas tungsten pulsed arc (U–GTPA) welding is proposed as a new alternative welding process to gas tungsten arc (GTA) welding. To better understand the advantages of this new process, in this paper, the microstructure, mechanical properties and corrosion behavior of GTA- and U–GTPA-welded joints of 316L stainless steel are systematically compared. These results show that the weld zone (WZ) depth-to-width ratio of the U–GTPA-welded joint increased, and the area of the equiaxed grain zone was larger than that of the GTA-welded joint. This results in finally increasing the strength and hardness for U–GTPA-welded joints, and the ultimate tensile strength and elongation of the U–GTPA-welded joints were 7.1% and 26.2% greater than those of the GTA-welded joint, respectively. For the U–GTPA-welded joint, under the action of the pulsed arc, the grain distribution with high-angle boundaries (HABs) was different from that of the GTA-welded joint. The minimum of the HAB fraction corresponded to the fracture position for both joints in tensile tests. It shows that a large number of HABs were beneficial in improving joint tensile properties. However, for electrochemical corrosion experiments of two WZs in 3.5% NaCl solution, despite this GTA WZ having a higher HAB fraction, the corrosion current density and corrosion potential of U–GTA WZ were lower and higher than those of the GTA WZ, respectively. The corrosion rate and corrosion sensitivity of U–GTPA WZ indicated good corrosion resistance.

中文翻译：

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气体钨极电弧（GTA）和超声辅助气体钨极脉冲电弧（U–GTPA）焊接的奥氏体不锈钢薄板接头的组织，力学性能和腐蚀行为

在此，提出了超声波辅助气体钨极脉冲弧焊（U–GTPA）作为气体钨极电弧焊（GTA）焊接的另一种替代焊接工艺。为了更好地了解这种新工艺的优势，本文系统地比较了316L不锈钢GTA和U-GTPA焊接接头的组织，力学性能和腐蚀行为。这些结果表明，U–GTPA焊接接头的焊缝区宽宽比增加，等轴晶粒区的面积大于GTA焊接接头的面积。这最终增加了U-GTPA焊接接头的强度和硬度，并且U-GTPA焊接接头的极限抗拉强度和伸长率分别比GTA焊接接头高7.1％和26.2％。对于U–GTPA焊接接头，在脉冲电弧的作用下，具有高角度边界（HABs）的晶粒分布不同于GTA焊接接头的晶粒分布。HAB分数的最小值对应于拉伸测试中两个接头的断裂位置。结果表明，大量的HAB有益于改善接头的拉伸性能。但是，对于两个WZ在3.5％NaCl溶液中的电化学腐蚀实验，尽管该GTA WZ具有较高的HAB分数，但U–GTA WZ的腐蚀电流密度和腐蚀电位分别低于和高于GTA WZ。U–GTPA WZ的腐蚀速率和腐蚀敏感性表明其良好的耐腐蚀性。HAB分数的最小值对应于拉伸测试中两个接头的断裂位置。结果表明，大量的HAB有益于改善接头的拉伸性能。但是，对于两个WZ在3.5％NaCl溶液中的电化学腐蚀实验，尽管该GTA WZ具有较高的HAB分数，但U–GTA WZ的腐蚀电流密度和腐蚀电位分别低于和高于GTA WZ。U–GTPA WZ的腐蚀速率和腐蚀敏感性表明其良好的耐腐蚀性。HAB分数的最小值对应于拉伸测试中两个接头的断裂位置。结果表明，大量的HAB有益于改善接头的拉伸性能。但是，对于两个WZ在3.5％NaCl溶液中的电化学腐蚀实验，尽管该GTA WZ具有较高的HAB分数，但U–GTA WZ的腐蚀电流密度和腐蚀电位分别低于和高于GTA WZ。U–GTPA WZ的腐蚀速率和腐蚀敏感性表明其良好的耐腐蚀性。U–GTA WZ的腐蚀电流密度和腐蚀电位分别低于和高于GTA WZ。U–GTPA WZ的腐蚀速率和腐蚀敏感性表明其良好的耐腐蚀性。U–GTA WZ的腐蚀电流密度和腐蚀电位分别低于和高于GTA WZ。U–GTPA WZ的腐蚀速率和腐蚀敏感性表明其良好的耐腐蚀性。