Microstructure and mechanical properties of dissimilar Al-Cu joints by friction stir welding  

铝-铜异种金属搅拌摩擦焊接头组织及力学性能（英文）

作　　者：张秋征[1] 宫文彪[1] 刘威[1] 

机构地区：[1]长春工业大学先进结构材料教育部重点实验室,长春130012

出　　处：《Transactions of Nonferrous Metals Society of China》2015年第6期1779-1786,共8页中国有色金属学报（英文版）

基　　金：Project(20140204070GX) supported by the Key Science and Technology of Jilin Province,China

摘　　要：Dissimilar friction stir welding between 1060 aluminum alloy and annealed pure copper sheet with a thickness of 3 mm was investigated. Sound weld was obtained at a rotational speed of 1050 r/min and a welding speed of 30 mm/min. Intercalation structure formed at the crown and Cu/weld nugget （WN） area promotes interracial diffusion and metallurgical bonding of aluminum and copper. However, corrosion morphology reveals the weak bonding mechanism of internal interface, which causes the joint failing across the interface with a brittle-ductile mixed fracture mode. The tensile strength of the joint is 148 MPa, which is higher than that of the aluminum matrix. Crystal defects and grain refinement by severely plastic deformation during friction stir welding facilitate short circuit diffusion and thus accelerate the formation of A14Cu9 and A12Cu intermetallic compounds （IMCs）. XRD results show that A14Cu9 is mainly in Cu/WN transition zone. The high dislocation density and formation of dislocation loops are the major reasons of hardness increase in the WN.对3 mm厚的1060工业纯铝和退火纯铜异种金属搅拌摩擦焊进行研究。在搅拌头旋转速度为1050 r/min、焊接速度为30 mm/min时,获得性能良好的铝/铜接头。交替片层结构主要分布于焊核区顶部与铜/焊核区交界附近,促进了铝、铜两种材料的界面扩散及铝和铜之间的冶金键合。然而,界面腐蚀形貌揭示界面内部的弱连接机制,导致拉伸试验中裂纹沿界面区域萌生和扩展,断裂方式为韧-脆混合型断裂。接头的抗拉强度为148 MPa,高于工业纯铝母材的抗拉强度。搅拌摩擦焊强烈塑性变形引起的晶体缺陷和晶粒细化加速原子间的短程扩散,从而促进金属间化合物Al4Cu9和Al2Cu的生成。XRD结果显示,金属间化合物Al4Cu9主要位于铜/焊核区过渡区域。焊核区较高的位错密度和位错环的形成是导致该区域硬度明显升高的主要原因。

关 键 词：aluminum alloy COPPER friction stir welding dissimilar material microstructure mechanical properties 

分 类 号：TG407[金属学及工艺—焊接]