摘要
搅拌摩擦焊接过程中被焊区材料发生剧烈塑性变形,进而导致焊缝微观组织及接头力学性能发生显著改变,但有关镁合金焊接接头弯曲性能的研究报道极少。本实验以铸造固溶态ZK60镁合金为研究对象,采用背弯和面弯两种弯曲试验方案,探索搅拌摩擦焊接ZK60镁合金的微观组织演变及对接头弯曲性能与断裂行为的影响规律。研究发现,焊接后焊缝区晶粒尺寸显著降低,平均晶粒尺寸从59μm左右降低至4μm左右。ZK60镁合金接头的弯曲性能远高于母材样品,且面弯样品的弯曲强度高于背弯样品。经过大挠度弯曲变形后ZK60母材及面弯试样都发生开裂,但背弯样品中未见裂纹的萌生及扩展。分析认为,接头过渡区/搅拌区界线处的织构突变对搅拌摩擦焊接ZK60镁合金的弯曲断裂行为影响不大。
Severe plastic deformation is occurred in weld zone during friction stir welding,which causes significant changes of microstructure and mechanical properties of the joints.But few studies are found on the bending properties of friction stir welded Mg alloys.In this paper,casting ZK60 Mg alloy in solid solution state was used as the research object.Two types of three-point bending tests,including surface test and root test,were used to explore the effect of microstructure evolution of ZK60 Mg alloy during friction stir welding on the bending strength and fracture beha-vior.It is found that significant grain refinement is observed in weld zone,and the average grain size is reduced from^59μm to^4μm.Friction stir welded ZK60 Mg alloy presents higher bending properties than that of the base metal sample.And the bending strength of surface test sample is higher than that of the root test sample.After a large deflection-strain bending test,both the base metal and surface test samples are cracked.But crack initiation and expansion is not observed in the root test sample.It is considered that abrupt change of texture at the boundary of transition zone/stir zone has little effect on the fracture behavior of friction stir welded ZK60 Mg alloy during bending tests.
作者
王向杰
冯蕾
武靖亭
肖新华
苏蓓蓓
WANG Xiangjie;FENG Lei;WU Jingting;XIAO Xinhua;SU Beibei(Department of Electromechanical Engineering,Hubei Polytechnic University,Huangshi 435003,China;Department of Traffic Engineering,Hubei Engineering Institute,Huangshi 435000,China;Aerospace Products Center,Tianjin Institute of Aerospace Mechanical and Electrical Equipment,Tianjin 300301,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第4期83-86,共4页
Materials Reports
基金
国家自然科学基金(51405146)
湖北省教育厅科学研究计划资助项目(D20184501
Q20184503)
湖北理工学院校级重点项目(17xjz02A)~~
