铝/铜电子束焊接头的显微组织与力学性能

摘要

采用对接方式对2 mm厚的T2紫铜板和2 mm厚的2A16铝合金板进行真空电子束焊。通过力学拉伸研究焊接速度、电子束流、扫描幅值对接头力学性能的影响，通过电镜扫描观察接头的显微组织形貌。结果表明：接头抗拉强度随着焊接速度、电子束流、扫描幅值的增大均呈先增大后减小的趋势；当焊接速度为1800 mm/min，电子束流为62 mA，扫描幅值为0.8 mm时抗拉强度达到最大值71 MPa。电子束流固有的冲击搅拌作用和其O型扫描作用对熔池中心组织有细化作用，会促进等轴块状相的生成，抑制组织的棒状生长。在熔池中心，各相的分布均匀，白色的网状化合物Al2Cu相遍布熔池中，暗灰色的Al相呈等轴块状被包裹在网状相的内部；靠铝侧热影响区相呈短棒状，紧靠铜侧的化合物层为Al2Cu层。%2.0 mm-thick T2 copper and 2.0 mm-thick 2A16 aluminum were welded by vacuum electron beam welding machine.The effects ofwelding velocity, electron beam and scanningmagnitudeonthe mechanical propertieswere studiedthrough the mechanical tensile.The microstructure of the joint was studied by SEM.The results show that, the tensile strength of joint increasesfirstlythen decreaseswith increasingthewelding speed, electron beam and the magnitude of scanning. When the welding speedis1800 mm/min,theelectron beam currentis62 mA, the magnitude of scanningis0.8 mm, the tensile strength reachesthe maximum of 71 MPa. The stirring action and O-scan of electron beam refine themicrostructureof molten pool and promotethe appearance of equiaxial massive phase. Each phase distributesuniformly in the pool. White Al2Cu compoundsarereticular in the center of molten pool. The dark gray Al phaseiswrapped by Cu-Al compounds andpresented equiaxed block. Phase near the HAZ of aluminum side is short rod. The compound layer close to the side of the copperisAl2Cu layer.