中文摘要：

针对钨极氩弧焊（GTAW）焊接紫铜厚板时热裂纹严重的问题,采用超声辅助GTAW新工艺研究紫铜板焊接工艺。通过动力学模拟得到超声辅助GTAW焊接时T3紫铜板振幅分布规律,确定焊接时超声入射的最佳位置,并发现超声功率越大,T3紫铜表面谐响应时对应的振幅越大。研究超声辅助钨极氩弧焊对T3紫铜焊缝显微组织和力学性能的影响。结果表明,经超声辅助后焊缝中热裂纹得到明显抑制,粗大柱状晶显著减少,焊缝中晶粒得到细化,等轴晶增加,有明显球化现象,出现明显亚晶界,在一定范围内,超声功率越大,细化效果越明显,亚晶尺寸半径越小。通过力学性能测试发现,焊接接头的硬度、屈服强度及延伸率与无超声作用时相比均有明显提升。

英文摘要：

Aiming at the serious problem of hot crack in copper plate welded by GTAW, adopt new technology of ultrasonic assisted GTAW research copper plate welding process. Firstly, assist T3 copper plate vibrated mode during welding by dynamic analysis and determine the most suitable area of uhrasonic in. And find that the more ultrasonic power, the greater amplitude corresponding to the harmonic response of the T3 copper surface. Secondly, study on the impact in T3 copper weld microstructure and mechanical properties of GTAW assisted by ultrasonic. The result shows that bulky columnar grains significantly reduce with ultrasonic assisted. In the weld joint, grains are refining and isometric crystals increase, bailing effect occurs ,and sub-grain boundaries appear. Within a certain range, the more ultrasonic power, the more obvious the refining effect is,the smaller radius of the crystal size. Through the mechanics performance test,find that the hardness, ensile strength, yield strength and ductility are greatly improved.