摘要
Welding joint of GH4169 alloy with a good formation was obtained. No macroscopic defects occurred in the joint. The weld had mainly a dendritic structure; the base metal was a solid solution of Ni, Cr, and Fe, and the strengthening-phase particles such as Ni3Nb were dispersively distributed along the grain boundary. The average tensile strength of the joint reached 743.7 MPa, and the Vickers hardness of the weld exceeded HV 300. Because of the segregation of the low-melting compound Ni3Nb at the grain boundary of the fusion zone, liquid cracks tended to occur as a result of welding stress. The formation of liquid cracks was inhibited by adding an alloying element, Mn, to the welding bath, because Mn diffused to the fusion zone and the high-melting phase Mn2Nb formed, and thus the overall properties of the joint were improved.
GH4169合金电子束焊接接头的成形良好,无宏观缺陷;焊缝为树枝晶组织,基体是Ni、Cr、Fe的固溶体,晶界上弥散分布着Ni3Nb等强化相颗粒;接头平均抗拉强度达到743.7MPa,但焊缝处的硬度超过维氏硬度HV300,熔合区晶界上低熔点化合物Ni3Nb在此偏聚,在焊接应力作用下易形成液化裂纹。在熔池中添加合金化元素Mn,扩散进入熔合区,形成高熔点化合物Mn2Nb相,从而抑制了液化裂纹的产生,并使接头的综合性能得到改善。
基金
Project(HIT.NSRIF.2014007)supported by the Fundamental Research Funds for the Central Universities,China
