工艺参数对Ti/Al异种金属搅拌摩擦焊接头抗拉强度的影响

Effect of Welding Process on Tensile Strength of Friction Stir Welded Ti/Al Dissimilar Joints

采用搅拌摩擦焊对3 mm厚TC4钛合金和2A14铝合金进行对接焊接,研究了搅拌头旋转速度、焊接速度和搅拌针偏移量(搅拌针中心线偏向铝合金母材后离母材对接面的距离)对焊接接头抗拉强度的影响规律。偏移量为1mm时,焊接接头容易产生裂纹、强度极低,增加偏移量有利于提高接头抗拉强度,偏移量为2.5 mm时,接头强度最高可达348 MPa。搅拌头旋转速度固定为800 r/min、偏移量固定为2.5 mm时,接头抗拉强度随焊接速度的增大先增大后减小,当焊接速度为40 mm/min时,接头的最高抗拉强度为335 MPa。当焊接速度固定为60 mm/min、偏移量为2.5 mm时,接头抗拉强度随旋转速度的增大先增大后减小,旋转速度为700 r/min时,接头的最高抗拉强度为348 MPa,达到铝合金母材强度的82.5%。

The butt joint of dissimilar metals, with 3mm thick of TC4 titanium alloy and 2A14 aluminum alloy, was welded by friction stir welding method. The influences of tool rotation speed, welding speed and pin offset （the distance of the tool pin centre to the contacted surface） on the tensile strength were investigated. When the offset is 1 mm, the joint is easy to crack and the tensile strength is low. The tensile strength increases with the offset increasing. When the offset is 2.5 ram, the highest tensile strength is 348 MPa. When the rotation speed is fixed at 800 r/min, the offset is fixed at 2.5 ram, the tensile strength of the joints increases first and then decreases with the increase of the welding speed. The highest tensile strength of the welded joint is 335 MPa, when the welding speed is 40mm/min. When the welding speed is fixed at 60 mm/min and the offset is 2.5 mm, the tensile strength of the welded joints first increases and then decreases with the increase of the rotation speed. The highest tensile strength of the joint is 348 MPa, when the tool rotation speed is 700 r/min, which is 82.5% of the aluminum alloy base metal.