TC4-DT钛合金电子束焊接接头的疲劳断口研究  

Fatigue appearance of TC4 - DT titanium alloy welded joints

作　　者：金宜振[1] 温家伶[1] 常明[1] 刘昕[2] 

机构地区：[1]武汉理工大学材料科学与工程学院,430070 [2]北京航空制造工程研究所高能束流加工技术国防科技重点实验室,100024

出　　处：《焊接》2012年第11期55-58,72,共4页Welding & Joining

基　　金：国家自然科学基金重点资助项目(50935008)

摘　　要：采用单边缺口试样,用扫描电镜观察了TC4-DT钛合金母材及电子束焊接接头焊缝区与热影响区的疲劳断口,分别分析了疲劳裂纹起裂源、扩展区及瞬断区的断口形貌特征。结果表明,疲劳裂纹均起裂于试样缺口根部,并由试样的一侧扩展到另一侧,裂纹扩展初期均沿一定的结晶面扩展,属于脆性穿晶断裂;母材和热影响区的瞬断部位均有明显的韧窝出现,属于塑性沿晶断裂,而焊缝区断口上韧窝不明显;热影响区疲劳断口有疲劳条带出现,但在母材和焊缝区断口上很难看见。The fatigue appearance of the base metal of TC4 - DT titanium alloy and different regions in welded joints by electron beam welding were observed through scanning electron microscope by using a single - edge notched specimen.The appearance characteristics of fatigue crack source,the propagation area and the fast fracture area were investigated.The results show that all the fatigue cracks initiate at the notch root of the specimen,and then propagate from the side to the other side.The cracks propagate along certain crystalline surface at the beginning period, which belongs to the brittle transgranular fracture.The dimple is obviously observed in the appearance of the fast fracture area of the base metal and the heat affect zone,which belongs to plastic intergranular fracture,but it is not obvious in the fracture appearance of the fusion zone.Fatigue bands are observed in the appearance of the heat affect zone.However,it was not very clear in the appearance of base metal and weld zone.

关 键 词：TC4一DT 钛合金 焊接接头 疲劳断口 

分 类 号：TG405[金属学及工艺—焊接]