电子束焊接钼接头的微观结构与力学性能研究

Study on Microstructure and Mechanical Properties of Electron Beam Welded Molybdenum Joint

为进一步提升钼接头的力学性能,采用电子束焊接方法,并分析接头的微观结构、力学性能和缺陷。实验结果表明:焊缝的平均硬度为210 HV,热影响区的平均硬度为202 HV,均高于母材;接头的均匀抗拉强度为280 MPa;断裂位置位于焊缝处,属于脆性断裂;断口位置位于焊缝中,被确定为准劈裂断裂;在焊接区观察到气孔和裂纹缺陷,气孔由熔池中未逸散的氧气形成,裂纹被确认为凝固裂纹和低塑性脆化裂纹。该研究结果可为钼接头力学性能的提升提供参考依据。

In order to improve the mechanical properties of molybdenum joint,electron beam welding method was used,and the microstructure,mechanical properties and defects of the jointw ere analyzed.The test results show that the average hardnesso f weld is 210 HV and the average hardness of heat affected zones i 202 HV,both of which are higher than that of base metal.Th e uniform tensile strength of the joint is 280 MPa;The fracturep osition is located in the weld,which belongs to brittle fracutre.The position of the fracture is located in the weld and is determiend to be quasi-split fracture.Porosity and crack defects wereo bserved in the welding zone.Porosity was formed by undispersed oxygenin the molten pool.The cracks were identified as solidification cracks and low plastic embrittlement cracks.The results can porvide reference for mechanical properties of molybdenum joint.