Mo-3Nb单晶管定向电子束焊接的组织及性能  

Microstructure and performance of orientation EB welding of Mo-3Nb single crystal

作　　者：姜玮[1] 郑剑平[1] 李鑫[1] 黄洪涛[1] 

机构地区：[1]中国原子能科学研究院,北京市102413

出　　处：《焊接》2016年第7期37-40,70,共4页Welding & Joining

摘　　要：对外径为20 mm,壁厚为4 mm的Mo-3Nb单晶管进行电子束定向焊接。利用光学显微镜背散射衍射(EBSD)等手段分析焊缝区域的断口形貌及显微组织,利用拉伸试验机和维氏硬度仪检测焊缝抗拉强度和硬度。结果表明,采用定向焊接获得的焊缝基本呈单晶状态,存在少量小角晶界。显微特点为无热影响区,熔池线清晰连续。焊缝区为薄弱区,抗拉强度略低于母材。焊接接头各区域硬度基本无差异,焊缝区与母材硬度基本相同。1 600℃热处理后显微结构与硬度均没有变化。Single crystal Molybdenum tube with 20 mm in diameter and 4 mm in thickness was welded by orientation electron beam welding.The microstructure,micro-hardness,fracture patterns and tensile strength of the welded joint were analyzed by OM,EBSD,hardness testing and tensile testing. The results show that the weld keeps the microstructure of the single crystal,although there is a little substructure in the center. There is no heat affected zone,and the fusion line is clear and continuous. The weld zone is the weak zone,and its tensile strength is less than that of the base metal. The micro-hardness of weld zone is almost the same with that of the base metal. After being annealed at1 600 ℃,the microstructure and the hardness of the weld are not changed.

关 键 词：单晶钼管 定向焊接 焊缝组织 显微硬度 退火 

分 类 号：TG442[金属学及工艺—焊接]