30mm厚TC4钛合金电子束焊接头的高周疲劳与裂纹扩展速率  

High cycle fatigue and crack growth rate of 30 mm thick TC4 titanium alloy electron beam welded joint

作　　者：贾金龙[1] 龙健 张林杰[2] Jia Jinlong;Long Jian;Zhang Linjie(Lanzhou Institute of Technology,Lanzhou 730050,China;State key laboratory of mechanical behavior for materials,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]兰州工业学院,兰州730050 [2]西安交通大学,金属材料强度国家重点实验室,西安710049

出　　处：《焊接》2024年第1期27-32,共6页Welding & Joining

基　　金：甘肃省高等教育教学成果培育项目(2021-JXCGPY131);甘肃省一流本科课程研究项目(2022-XXKC-150);陇原青年创新创业人才团队项目。

摘　　要：文中对比研究了30 mm厚TC4钛合金电子束焊接头和母材的高周疲劳性能,发现接头的高周疲劳性能与母材非常接近。在文中试验条件下,电子束焊接头在循环周次为2×10^(6)时的高周疲劳强度为474 MPa,达到母材的94.2%。观察电子束焊接头和母材的高周疲劳断口形貌,发现接头和母材的疲劳源均位于试样表面。疲劳裂纹扩展区都发现疲劳辉纹,相同载荷条件下,母材高周疲劳断口中辉纹的间距较小,约为1.49μm,电子束焊接头的相邻辉纹间距为2.14μm。在接头和母材的疲劳瞬断裂区还发现大量韧窝,呈现出典型的韧性断裂特征。文中还对比了母材、热影响区和焊缝区的疲劳裂纹扩展速率,发现热影响区的抗疲劳裂纹扩展性能最弱。分析认为,热影响区的高硬度是导致其抗疲劳裂纹扩展性能弱于其他区域的重要原因。High cycle fatigue properties of 30 mm thick TC4 titanium alloy electron beam welded joints and base material were compared and studied in this paper,it was found that high cycle fatigue performance of welded joints was very close to that of base material.Under the experimental conditions,high cycle fatigue strength of electron beam welded joints was 474 MPa when number of cycles was 2×10^(6),reaching 94.2%of base material.By observing high cycle fatigue fracture morphology of welded joints and base material,it was found that fatigue sources were located on the samples’surface of welded joints and base material.Fatigue cracks were found in the fatigue crack growth area.Under the same load condition,spacing of scratches in the high cycle fatigue fracture of base material was smaller,about 1.49μm,and spacing of the adjacent scratches of electron beam welded joints was 2.14μm.A large number of dimples were found in the final tensile fracture area of welded joints and base material,showing characteristics of ductile fracture.Fatigue crack propagation rate of base material,heat affected zone and weld zone was also compared in this paper,and it was found that fatigue crack propagation resistance of heat affected zone was the weakest.It was concluded that high hardness of heat affected zone was an important reason for its weaker anti-fatigue crack growth performance than other areas.

关 键 词：钛合金 电子束焊接 高周疲劳 裂纹扩展速率 

分 类 号：TG405[金属学及工艺—焊接]