6061-T4铝合金搅拌摩擦焊T型接头缺陷及性能  

Defects and Properties of Friction Stir T-Welded Joints for 6061-T4 Aluminum Alloy

作　　者：周光[1] 杨新岐[1] 徐效东[1] 张照华[1] 

机构地区：[1]天津大学材料科学与工程学院天津市现代连接技术重点实验室,天津300072

出　　处：《航空材料学报》2012年第4期26-31,共6页Journal of Aeronautical Materials

基　　金：国家自然科学基金资助项目(50775159)

摘　　要：对板厚3mm的6061-T4铝合金T型接头进行搅拌摩擦焊接研究并具体讨论了旋转速率(ω)及焊接速率(v)对焊接缺陷及力学性能的影响。结果表明:对给定的夹具形式和搅拌工具,当v不变时焊缝前进侧筋板圆角过渡处容易产生随ω/v增大而减小的隧道缺陷,后退侧圆角区易出现清晰的"Z"连接线;壁板出现两个随ω增大而扩大的软化区域,而壁板焊缝中心的硬度随ω增大而升高;T型接头筋板焊缝热力影响区同样被软化,其硬度较母材降低17.0%;局部组织软件是造成所有接头沿壁板方向加载抗拉强度下降的重要原因,其最高抗拉强度只达到母材的73.8%,隧道缺陷是引起ω=1008r/min筋板方向强度降低的主要原因,而ω=1541r/min和ω=2256r/min筋板方向强度降低主要归结于T型接头中热力影响区组织的软化,其中当ω/v=1541/218 r/mm时,沿T接筋板方向抗拉强度最高可达到母材的83.5%。The processes of friction-stir-welded T-joints for 3mm thick AA 6061-T4 were investigated, and the influences of welding speeds and rotating speeds on welding defects and mechanical properties were discussed specifically. It was found that for given fixture and tool, when v was kept constant, tunnel defects were easily produced at the fillet corner of stringer nugget along advancing side which became smaller with the increasing to/v. Clear ＂Z＂ line was tended to appear near the retreating side. Two soften zones that were enlarged with the increasing to were found in the skin. The hardness in the center of weld was increased with the to increased. The stringer thermo-mechanically affected zone was also softened and its hardness was reduced 17.0%. The decreased hardness was the main factor to reduce the tensile strength of all T-joints along skin direction. The best tensile strength was only up to 73.8% compared to base material. Tunnel defect was the main reason to reduce tensile strength in the stringer direction for to = 1008r/min. And the softer microstructure of thermal mechanical affected zone in T-joints was contributed to the decrease of tensile strength forω = 1541r/min andω = 2256r/min. The highest tensile strength reaches to 83.5% of the base material whenω/v = 1541/218 r/mm.

关 键 词：搅拌摩擦焊 T型接头 焊接缺陷 力学性能 

分 类 号：TG453.9[金属学及工艺—焊接]