沿板厚方向TC18钛合金厚板电子束焊接接头组织及疲劳性能研究  

Study on Microstructure and Fatigue Properties of Electron Beam Welded Joints of TC18 Titanium Alloy Plate along Thickness

作　　者：韩文 傅莉[1] 陈海燕[1] HAN Wen;FU Li;CHEN Haiyan(Shaanxi Key Laboratory of Friction Welding Technologies, Sate Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China;The First Aircraft Institute, Xi＇an 710089, China)

机构地区：[1]西北工业大学凝固技术国家重点实验室陕西省摩擦焊接重点实验室,陕西西安710072 [2]航空工业第一飞机设计研究院,陕西西安710089

出　　处：《热加工工艺》2018年第7期45-48,共4页Hot Working Technology

基　　金：陕西省重点科技创新团队计划项目(No.2014KCT-12)

摘　　要：采用电子束焊接的方法,实现了15 mm厚TC18钛合金板材对接焊。利用光学显微镜、扫描电子显微镜及透射电子显微镜对接头的宏观形貌、显微组织及断口特征进行分析,并用电子万能试验机测试了接头沿板厚方向的疲劳性能。结果表明,焊缝区主要由柱状的β相和针状的α马氏体相组成。沿板厚方向从上到下,晶粒尺寸逐渐变小,导致焊接接头疲劳性能逐渐增加。接头疲劳断口可分为疲劳裂纹源区、扩展区和瞬断区三个典型区域,裂纹都起源于试件表面。The butt welding of 15 mm TC18 titanium alloy thick plate was realized by electron beam welding. The macro morphology of the joint, microstructure and fracture characteristics were analyzed by optical microscopy, scanning electron microscopy and transmission electron microscopy, the fatigue properties of the welded joints were studied and tested along the thickness direction by an electronic universal testing machine. The results show that the weld zone is mainly composed of columnar β phase and acicular α martensite phase. From the top to the bottom, the grain size gradually decreases along the thickness direction, which results in the increase of fatigue properties of the welded joints. The fatigue fracture of the joints can be divided into three typical regions of fatigue crack source zone, expansion zone and instantaneous zone, and the fatigue cracks of joints originate from the surface of the specimens.

关 键 词：电子束焊接 S-N曲线 疲劳性能 

分 类 号：TG456.3[金属学及工艺—焊接]