摘要
采用新型超声振动辅助搅拌摩擦焊接设备实现了4 mm厚的2195铝锂合金轧制板的焊接,比较和分析了施加超声对焊缝宏观金相组织、显微硬度与接头拉伸性能的影响,研究了工艺参数对铝锂合金超声振动辅助搅拌摩擦焊缝成形及接头力学性能的影响规律。结果表明:在相同工艺参数条件下,施加超声振动能量能够改善2195铝锂合金搅拌摩擦焊接成形性,促使焊核区塑性材料流动增强,同时减少甚至消除常规搅拌摩擦焊接头内部的孔洞缺陷;在焊缝的上部及中部,由于超声的作用,焊核区的显微硬度得以提高,而焊缝底部变化不大;接头的断口均呈现出韧性断裂模式,施加超声振动能量后的接头的伸长率得以提高,其断口韧窝更加细小均匀;在所研究的工艺参数范围内,接头的最高抗拉强度为282.8 MPa,最大伸长率为11.5%。在转速为600 r/min,焊接速率为225 mm/min条件下,施加超声使接头抗拉强度提高了17.5 MPa,伸长率提高了3.7%。
A novel ultrasonic vibration enhanced friction stir welding(UVeFSW)process was employed to join the rolled 2195 aluminium-lithium alloy of 4 mm thickness.The effects of superimposing ultrasonic on the macro metallograph,microhardness and tensile properties of welded joints were compared and analyzed.The effect of process parameters on the weld formation and joint mechanical properties of aluminium-lithium alloy by ultrasonic vibration enhanced friction stir welding was investigated.The results show that under the same process parameters superimposing ultrasonic energy in friction stir welding can improve the formability of 2195 aluminium-lithium alloy and enhance the plastic material flow in the weld nugget zone,which can reduce or even eliminate the void defect in the conventional friction stir welding joint.The microhardness at the top and middle of the nugget zone increases due to the ultrasonic effect,while the bottom of the weld does not change much.The fracture surfaces of the joints show a ductile fracture mode,and the elongation of the joints increases after ultrasonic vibration energy is applied,and the fracture dimples are more fine and uniform.Under the welding parameters studied the maximum tensile strength and elongation of the joint are 282.8 MPa and 11.5%,respectively.Under the conditions with rotational speed of 600 r/min and welding rate of 225 mm/min,the application of ultrasound can improve the tensile strength and the elongation of the joint by 17.5 MPa and 3.7%respectively.
作者
石磊
戴翔
武传松
傅莉
SHI Lei;DAI Xiang;WU Chuan-song;FU Li(Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education),Shandong University,Jinan 250061,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2021年第5期122-129,共8页
Journal of Materials Engineering
基金
国家自然科学基金项目(51905309)
西北工业大学凝固技术国家重点实验室开放课题(SKLSP201912)。
关键词
铝锂合金
搅拌摩擦焊接
超声振动
力学性能
aluminium-lithium alloy
friction stir welding
ultrasonic vibration
mechanical property
