(兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050)
摘 要: 采用ER4047铝硅焊丝对5052铝合金与T2紫铜进行脉冲旁路耦合电弧MIG熔钎焊，并对接头显微组织、物相成分及力学性能进行分析。结果表明：通过控制焊接热输入可以获得成形良好的铝/铜熔钎焊搭接接头。焊接接头由铝侧熔合区、焊缝区和铜侧类钎焊区组成，其中铜侧类钎焊区可分为金属间化合物层区和Al-Cu共晶区两部分。焊缝区组织为珊瑚状Al-Cu共晶体均匀分布在α(Al)固溶体中；铜侧金属间化合物层主要由条块状Al2Cu组成。随着焊接热输入的增大，金属间化合物层的厚度在增大，而接头的抗拉强度先增大后减小；当熔化的焊丝及铝母材在铜母材上润湿良好并且焊缝与铜母材之间金属间化合物的厚度较小时，接头抗拉强度达到最大值，为167.7 MPa。
关键字: 铝/铜异种金属；热输入；显微组织；金属间化合物；力学性能
（State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:5052 aluminum alloy and T2 copper dissimilar metals were welded using 4047 AlSi12 wire by pulsed DE-MIG welding-brazing. The microstructure, elements composition and mechanical properties of joint were studied. The results show that it is feasible to obtain a favorable welding-brazing joint of Al-Cu by controlling the welding heat input. The welding joint is composed of fusion zone of the aluminum side, the weld zone and brazing zone of the copper side which is divided into two parts, Al-Cu eutectic zone and Al-Cu IMC layer zone. The microstructure of the weld zone is coral Al-Cu eutectic distributed in α(Al) solid solution, and IMC layer of Cu side mainly consists of strip Al2Cu. The tensile strength of joint firstly increases, and then decreases with the increase of welding heat input. When the wettability of wire and aluminum on the copper is good, and the thickness of IMC layer between the welding seam and the Cu base metal is relatively small, the tensile strength of joint can reach up to 167.7 MPa.
Key words: Al/Cu dissimilar metal; heat input; microstructure; intermetallic compound; mechanical property
