铝/钢FSW接头界面层组织和力学性能的研究

Study on Interface Layer Microstructure and Mechanical Properties of Aluminum/Steel FSW Joint

研究了焊接速度对铝/钢异种金属搅拌摩擦焊(FSW)搭接接头宏观形貌、界面层显微组织和拉剪载荷的影响。结果表明:采用铝板在上,钢板在下的搭接接头形式,搅拌针进入钢板焊接,可以获得拉剪载荷较高的焊接接头;焊接速度较低时,焊核处出现的"洋葱瓣"状结构和界面层的冶金结合对接头强度起主要作用,随着焊接速度的提高,焊核处出现了隧道式孔洞,"洋葱瓣"状结构趋于不明显,界面结合宽度减小,界面层冶金反应有减弱的趋势,从而导致了接头拉剪破坏载荷降低。

The effects of welding speed on the macroscopic feature, interface layer and tensile shear load of Al/steel dissimilar metal FSW joints were investigated. The results show that, during friction stir welding proeess, the aluminum sheet is put on the steel sheet as a lap joint. The aluminum/steel dissimilar metal joint with good strength can be obtained by pressing the friction pin into the steel sheet. The onion petal-like structure at welding nugget appears in low welding speed and metallurgical bonding at the interface layer plays major roles in the joint strength. With the improvement of welding speed, onion petal-like structure tends to be inconspicuous, a tunnel through-hole appears at the nugget, the width of interfacial layer decreases, the metallurgical reaction of the interface layer weakens gradually, therefore, the tensile shear load of the welded joint reduces.