摘要
针对单晶炉用4 mm板厚TU1铜部件进行对接搅拌摩擦焊(Friction stir welding,FSW)工艺试验,探讨焊接工艺参数对焊缝成形、组织特征、力学性能及导电率的影响规律。结果表明,在主轴转速ω=300~1000 r/min与焊接速度v=60~200 mm/min范围内均可获得表面光滑无内部缺陷的对接焊缝,接头外观尺寸可精确控制且基本无残余焊接变形。接头主要由焊核(Stirring zone,SZ)、热影响区(Heat affect zone,HAZ)及母材(Base material,BM)组成,未观察到热力影响区(Thermal mechanical affect zone,TMAZ)。在300 r/min下SZ和HAZ晶粒组织具有明显差异,随主轴转速增加SZ与HAZ组织差异不断减小。在800 r/min时可获得SZ和HAZ与母材基本相同晶粒组织特征,焊接速度变化对SZ和HAZ组织差异影响较小。接头硬度分布不均匀,当转速超过600 r/min时SZ和HAZ存在明显软化现象,最薄弱区位于HAZ。接头电导率在99.5%~102.5%IACS范围变化,其中SZ电导率优于BM、而HAZ电导率低于BM。在焊接工艺300 r/min-60 mm/min下接头抗拉强度达到BM的90%以上,断后伸长率为14.5%以上;断口呈现优异韧性断裂特征。
Friction stir welding(FSW)was performed for TU1 oxygen-free copper sheet with 4mm thickness to investigate the influences of welding parameters on the weld formation,microstructure,mechanical properties and electrical conductivity.It is shown that the butt weld with a smooth surface and no internal defects can be obtained in the range of 300-1000 r/min rotational speeds and 60-200 mm/min welding travel speeds.The appearance dimension of the joint can be accurately controlled and there is basically no residual welding deformation.The weld zone is mainly composed of the Stirring zone(SZ),the heat affect zone(HAZ)and the base material(BM).There is no thermal mechanical affected zone(TMAZ)observed.The grain sizes have obvious differences in the SZ and HAZ under the condition of 300 r/min,and the differences in grain sizes between SZ and HAZ are gradually reduced with the increase of rotational speed.The same grain sizes can be obtained approximately among SZ,HAZ and BM under the condition of 800 r/min,and variation of welding speed has a small influence on the difference of grain size between SZ and HAZ.The hardness distribution in the weld zone is uneven,the obvious soften zone is produced in the SZ and HAZ when the rotational speed is greater than 600 r/min,and the HAZ has the lowest hardness.The conductivity of SZ is better than that of BM,while the conductivity of HAZ is lower than that of BM,and the average conductivity in the weld is in the range of 99.5%-102.5%IACS.When the welding parameters are 300 r/min-60 mm/min,the tensile strength of the welded joint is more than 90%of the base metal,and the elongation is more than14.5%.The fracture mode presents excellent ductile fracture characteristics.
作者
徐永生
杨新岐
唐文珅
靳立辉
姚长娟
刘旭光
XU Yongsheng;YANG Xinqi;TANG Wenshen;JIN Lihui;YAO Changjuan;LIU Xuguang(School of Materials Science and Engineering,Tianjin University,Tianjin 300350;Tianjin Huanbo Technology Co.,Ltd.,Tianjin 300071)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2023年第14期116-129,共14页
Journal of Mechanical Engineering
基金
天津市科技支撑重点资助项目(19YFZCGX01060)。
关键词
TU1无氧铜
搅拌摩擦焊
组织特征
力学性能
电导率
TU1 copper
friction stir welding
microstructure features
mechanical properties
electrical conductivity
