A7N01P-T4铝合金对-搭接结构的搅拌摩擦焊技术研究

通过采用不同的搅拌针偏移位置,对A7N01P-T4铝合金对-搭接结构进行搅拌摩擦焊接(FSW)试验,研究该工艺的桥接性,并分析其对接头组织和性能的影响。结果表明,在不同偏移位置下,均可获得成形良好的焊接接头,其组织主要由母材区、焊核区、热影响区以及热机影响区构成,但接头中存在钩状(hook)缺陷、S线和冷搭接缺陷,从而影响接头质量。当搭接贴合面置于后退侧时,若搅拌针向内偏移,S线对接头的危害显著增加,极大降低了接头的力学性能(最大载荷仅2.03kN);若搅拌针向外偏移,则冷搭接尺寸增加,但对接头性能(最大载荷为15.86～15.96kN)的影响不明显;当搭接贴合面置于前进侧时,S线对接头性能无明显影响,且搅拌针偏移对钩状缺陷尺寸与形状的影响较小,因而对接头性能影响不大(最大载荷为12.76～12.94kN),虽然该方式下最大载荷低于前者,但接头性能稳定性更好。此外,FSW技术在铝合金对-搭接结构的焊接中表现出了较好的桥接能力。

Friction Stir Welding of Butt-lap Structure of A7N01P-T4Aluminum Alloy

Friction stir welding(FSW)experiments of A7N01P-T4 aluminum alloy butt-lap structure were carried out by using different stirring pin offset modes.The bridging characteristics,microstructure and properties of FSW were analyzed.The results show that the butt-lap structure can obtain the satisfied joints under different offset modes.The joint is mainly composed of base material zone,nugget zone,heat affected zone and thermo-mechanically affected zone.However,the joints appears in hook defect,S-line or cold lap defect,which can affect the quality of the joints.When the lap surface is set on the retreating side(RS),and the stirring pin is inward,the S line can increase the damage to the joints and reduce greatly the load of joints(2.03kN),while the pin is outward,the size of the cold lap is increased,howeever it has a little effect on the performance of joint(15.86-15.96kN).When the lap surface is et on the advanced side(AS),the S line has no obvious effect on the performance of joint.Meanwhile,the pin offset presents slight effects on the hook defects,so it has a little effect on the performance of joint(12.76-12.94kN).Although the maximum load is lower than the former one in this mode,the stability of joint performance presents more desirable.Furthermore,FSW technology shows a better bridging ability in the welding of aluminum alloy butt-lap configuration.