超声冲击对TC4钛合金激光焊接接头疲劳性能的影响  

Ultrasonic Impact Treatment on Fatigue Properties of Laser Welded Joints of TC4 Titanium Alloy

作　　者：丛家慧 徐永臻 王磊 回丽 黄秉汉 Cong Jiahui;XuYongzhen;Wang Lei;Hui Li;Huang Binghan(Department of Mechanical and Electrical Engineering,Shenyang Aerospace University,Shenyang 110136,China;School of Mechanical Engineering,Suzhou University of Science and Technology,Suzhou 215009,China;Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process,Shenyang Aerospace University,Shenyang 110136,China)

机构地区：[1]沈阳航空航天大学机电工程学院,辽宁沈阳110136 [2]苏州科技大学机械工程学院,江苏苏州215009 [3]沈阳航空航天大学航空制造工艺数字化国防重点学科实验室,辽宁沈阳110136

出　　处：《稀有金属》2022年第11期1414-1421,共8页Chinese Journal of Rare Metals

基　　金：国家重点实验室开放基金项目(VCAME201908);国防重点实验室开放基金项目(SHSYS201901);国家自然科学基金项目(51775355);辽宁省教育厅项目(JYT2020037)资助。

摘　　要：为了改善TC4钛合金焊接接头的性能,延长其疲劳寿命,采用超声冲击(UIT)处理方法对TC4钛合金激光焊接接头进行处理,对比分析了冲击前后试样的微观组织、显微硬度、疲劳性能、残余应力和断口形貌。结果表明,经过超声冲击处理后,试样表层晶粒细化,形成塑性变形层,表面显微硬度平均提高了12%,疲劳寿命提高了2.1倍,残余压应力有了明显提升,平均应力可达-500 MPa,裂纹细小且只在内部扩展,疲劳裂纹萌生位置转移至次表面,疲劳条带间距变小,韧窝变密,有效改善了TC4钛合金激光接头的疲劳性能。With the development of the aerospace industry,the design requirements for aircraft range,safety and reliability and environmental protection were increasing,so reducing the weight of aircraft structure and improving service reliability and longevity were the main goals of current research.TC4 titanium alloy had become a kind of lightweight and high-strength structural material with a wide range of uses due to a series of advantages such as ultra-high specific strength,good corrosion resistance and high temperature resistance.Laser welding was used in precision manufacturing fields such as aviation and aerospace due to the advantages of concentrated heat input,rapid heating,small thermal damage and small deformation,and was especially suitable for the connection of titanium alloy thin plates.Laser welding of titanium alloy plates was prone to defects such as undercuts and pores,which made the welded joints had stress concentration during the load-bearing process,and the surface defects of titanium alloys were highly sensitive to fatigue cracks under the action of cyclic loading.Therefore,the use of a reasonable process to strengthen the welding joint could improve the safety of the welding workpiece and prolong the service life,which had important engineering significance.Ultrasonic impact treatment(UIT)could form a relatively continuous,uniform and smooth transition arc at the weld toe,and could effectively alleviate the stress concentration of the welded joint.It had become a new method in recent years to improve the overall performance of the welded joint.This paper was the use of ultrasonic impact on TC4 titanium alloy laser welded joints,comparing the fatigue properties before and after ultrasonic impact,and then from the microstructure,microhardness,residual stress,fracture morphology and other aspects of the comparison and analysis,to explore the impact of ultrasonic impact on the fatigue properties of TC4 titanium alloy laser welded joints.The test plate was laser welded after mechanical treatment.After w

关 键 词：超声冲击(UIT) TC4钛合金 激光焊接 疲劳性能 

分 类 号：TG178[金属学及工艺—金属表面处理]