2519厚板搅拌摩擦焊接工艺及组织分析

来源期刊：中南大学学报(自然科学版)2006年第1期

论文作者：周鹏展 钟掘 贺地求 舒霞云

文章页码：114 - 118

关键词：搅拌摩擦焊; 2519铝合金;抗拉强度;显微组织

Key words：friction stir welding; 2519 Al alloy; tensile strength; microstructure

摘    要：采用搅拌摩擦焊接方法对厚度为12 mm的2519铝合金板进行焊接试验。实验结果表明:在焊接速度为140 mm/min,旋转速度为1 800~2 200 r/min时,随着旋转速度的增加,焊缝强度先增加后减小;在旋转速度为2 000 r/min时,可以获得较好的焊接接头,抗拉强度达到最大值296 MPa,断裂形式为韧性和脆性的混合型断裂。光学显微镜、扫描电子显微镜和电子能谱分析结果表明:焊缝中组织的差异及晶界上粗大的富铜析出相是导致焊缝强度低于基材强度的原因;焊缝中的组织差异及晶界富铜析出相的形成是焊缝区温度沿板厚的急剧变化和搅拌力综合作用的结果。

Abstract: Friction-stir-weld of 2519 aluminum plate in 12 mm thickness was completed. The experiment result shows that the welds′mechanical properties increase first and then decrease with rotating speed increasing from 1 800 r/min to 2 200 r/min at welding speed of 140 mm/min.When the rotating speed is 2 000 r/min and the welding speed is 140 mm/min, good weld of 2519alloy is achieved. The maximum tensile strength of the weld is 296 MPa and the fracture mode is ductile and brittle mixed fracture. Through optical microscope, scanning electron microscope and energy dispersive spectroscopy analysis, it can be concluded that the weld s tensile strength lower than that of base metal result from the microstructure difference and the bulky Cu-rich precipitation at grain boundary in the weld and the microstructure difference and the bulky Cu-rich precipitation at grain boundary are formed by the interaction of acute change of temperature and force.