6061铝合金无倾角搅拌摩擦焊工艺及性能

Processes and Properties of Friction Stir Welding Joint of 6061 Al-alloy with Zero Title Angle

目的为了适应空间曲面构件的搅拌摩擦焊,开展6061铝合金无倾角搅拌摩擦焊工艺及性能的研究。方法采用无倾角搅拌摩擦焊用的搅拌头,对5 mm厚6061-T6铝合金板材进行试验,研究焊缝成形及接头力学性能,并分析接头组织特征。结果零倾角搅拌摩擦焊接头从组织上可区分为5个不同区域:焊核区(WNZ)、热力影响区(TMAZ)、热影响区(HAZ)、轴肩影响区(SAZ)和母材(BM);随着搅拌头转速增加,焊缝宽度和焊核尺寸均先变大后变小;随焊接速度增加,焊缝宽度和焊核尺寸均逐渐变小;当焊接速度固定时,随搅拌头转速增加,接头拉伸强度先增加后减小;当搅拌头转速固定时,随焊接速度增加,接头拉伸强度逐渐增大。结论采用无倾角搅拌摩擦焊接方法,能够实现对5 mm厚6061-T6铝合金板材的有效焊接。

The paper aims to adapt to friction stir welding for part with curved surface and study processes and mechanical properties of friction stir welding joint of 6061 Al-alloy with zero title angle. Special designed tool for zero title angle friction stir welding was used to test 5 mm thick 6061-T6 Al-alloy. The microstructure and mechanical property of the joint were researched. The results show that the joint of zero title angle friction stir welding could be divided into 5 regions according to the structures： Weld Nugget Zone, Thermal Mechanical Affected Zone, Heat Affected Zone, Shoulder Affected Zone and Base Metal. With the increase of rotational speed, the weld width and weld nugget size increased firstly and then decreased. With the increase of welding speed, the weld width and weld nugget size decreased gradually. At fixed welding speed, tensile strength of joint increased firstly and then decreased with the increase of rotational speed. At fix rotational speed, tensile strength of joint increased with increasing welding speed. Finally, the experiments prove that 5 mm thick 6061-T6 Al-alloy can be welded well with the designed tool for zero title angle friction stir welding.