NiCuNbCr焊料Ti_3Al/GH4169合金氩弧焊接头的组织及性能

Microstructure and Mechanical Properties of Ti_3Al/GH4169 Superalloy Joints Arc Welded with NiCuNbCr Filler Alloy

采用钨极氩弧焊方法,使用自行设计制备的NiCuNbCr合金作为焊料,实现Ti3Al基合金与GH4169高温合金异种材料之间的焊接。采用扫描电镜(SEM)及能谱分析(XEDS)等方法对接头横截面的微观组织进行分析。结果表明:GH4169/焊缝界面以及焊缝均主要由Ni元素的固溶体组成,其中固溶了Cu,Fe,Cr,Nb几种元素;而焊缝/Ti3Al界面分为3层组织,其相组成从Ti3Al母材到焊缝方向依次为:固溶了Ni和Cu元素的Ti2AlNb相、Al(Ni,Cu)2Ti金属间化合物及(Nb,Ti,Mo)固溶体;(Ni,Nb,Cr)及Ni(Cu,Ti)固溶体;Ni的固溶体,固溶元素为Cu,Nb和Cr。接头的平均室温抗拉强度为140.7MPa。拉伸试样断裂于被焊Ti3Al母材表面的扩散反应层,它主要由固溶了Ni和Cu元素的Ti2AlNb相与Al(Ni,Cu)2Ti金属间化合物组成,该界面是Ti3Al/GH4169接头的薄弱环节。

With a NiCuNbCr alloy as filler material,dissimilar welding of a Ti3 Al-based alloy and a Nibased superalloy （GH4169） was successfully carried out using gas tungsten arc （GTA） welding technology.The microstructure evolution along the cross section of the dissimilar joint was analyzed with the scanning electron microscopy （SEM） and X-ray energy dispersive spectroscopy （XEDS） method.The results show that,both the GH4169/weld interface and the weld consist of Ni solid solution,dis solve with several elements of Cu,Fe,Cr and Nb.The weld/Ti3Al interface is composed of three transitional layers.The phase constitutions of the layers from the Ti3Al side to weld are：Ti2 AlNb matrix dissolving with Ni and Cu,Al（Ni,Cu）2Ti intermetallics as well as （Nb,Ti,Mo） solid solution; （Ni,Nb,Cr） and Ni（Cu,Ti） solid solution; Ni solid solution,dissolving with Cu,Nb and Cr,respectively.The average room-temperature tensile strength of the joints is 140.7MPa.The fracture occurrs at the diffusion reaction layer at the surface of the joined Ti3Al base alloy,which is mainly composed of Ti2AlNb matrix dissolving with Ni and Cu as well as Al（Ni,Cu）2Ti intermetallics.This interface should be the weak link of the Ti3Al/GH4169 joint.