TC18钛合金电子束焊接接头DFR常规及腐蚀疲劳对比研究(英文)  

Comparative Study on DFR of Electron Beam Welded TC18 Joints in Conventional and Corrosive Environment

作　　者：韩鹏[1] 毛智勇[1] 余伟[1] 王西昌[1] 付鹏飞[1] 

机构地区：[1]北京航空制造工程研究所高能束流加工技术重点实验室,北京100024

出　　处：《稀有金属材料与工程》2013年第S2期213-216,共4页Rare Metal Materials and Engineering

基　　金：NSFC(50935008)

摘　　要：通过对TC18钛合金电子束焊接接头在常规和3.5%NaCl水溶液腐蚀环境下的DFR腐蚀疲劳试验对比研究,试验结果计算得到在常规环境下TC18钛合金焊接件的疲劳额定强度截止值为725 MPa,其疲劳额定强度截止值为554 MPa,在腐蚀环境下,疲劳额定强度截止值下降23.6%。断口分析表明,疲劳断口有疲劳源区、疲劳裂纹扩展区和瞬断区3部分组成。疲劳寿命越长,裂纹扩展段也越长,裂纹扩展的条纹越细。在腐蚀疲劳条件下,同时有多条疲劳裂纹形成,并沿垂直于拉应力方向扩展,疲劳断口呈现多平面特征。断口表面可以发现较多的盐颗粒,说明在腐蚀溶液的作用下,盐溶液沿着疲劳裂纹的渗透性很强,在疲劳裂纹带上可以发现很多网状的盐颗粒,对TC18钛合金电子束焊接接头的疲劳性能有一定影响。DFR(detail fatigue rating) of electron beam welded joints for TC18 titanium alloy in conventional environment was compared with that in 3.5%NaCl aqueous solution corrosive environment.The results show that in conventional fatigue test,the DFR of TC18 titanium alloy welded joints is 725 MPa,that in corrosive environment is 554 MPa,and that of TC18 titanium alloy welded joint is decreased by 23.6% in corrosive environment.Largely by the morphology diagram it can be found that the fatigue fracture can be divided into three parts,fatigue source area,the fatigue crack growth area and instantaneous off region.In the longer life of the specimen,the crack growth segment is longer,the stripes of crack propagation is finer.In the condition of corrosion fatigue,multiple fatigue crack formation,and along the vertical direction of extension in tensile stress,fatigue fracture presents multi-dimensional features.More salt granules are on the surface of the fracture,while in the corrosive solution,salt solution infiltration of fatigue crack along is very strong.It can be found that the fatigue crack propagation with lots of salt particle in mesh influences TC18 fatigue properties of electron beam welded joint of titanium alloys.

关 键 词：TC18钛合金 电子束焊接接头 疲劳额定强度截止值 腐蚀疲劳 

分 类 号：TG456.3[金属学及工艺—焊接]