异质钛合金线性摩擦焊接头界面行为分析

The Analysis in Linear Friction Welding Joint Interface Behavior of Dissimilar Titanium Alloy

在线性摩擦焊机上进行了TC4/TC17异质钛合金线性摩擦焊实验研究。焊后利用光学显微镜、扫描电镜以及透射电镜等对焊接接头界面微观组织进行了分析。结果表明,线性摩擦焊接头界面结合良好,通过对接头焊缝界面及热机械影响区组织特点的分析发现,在摩擦焊接过程中焊缝区在热力耦合作用下界面温度超过β相变温度,在焊后冷却过程中发生相变再结晶,产生细小的针状组织.焊缝界面的组织过渡区发生明显的再结晶,部分组织产生等轴化甚至球化现象。在再结晶边缘区域位错密度较高,界面组织过渡区没有发现大量位错存在。

The dissimilar titanium alloy TC4/TC17 was welded on a linear friction welding machine.After welding,optical microscope,SEM and TEM were used to analyze the microstructure of the welded joint.The results indicated a sound bonding interface.The microstructural features of both the weld and thermomechanically affected zone（TMAZ） are characterized for the weld.It was found that in the weld region,exposure to supertransus temperatures combined with hot-deformation working,and cooling after joining,resulted in recrystallization of the beta grain structure that had a refined needle-like structure.The recrystallization occurred in the mixture zone of the welded joint interface,and in particular,part of the microstructure equiaxed and even spheroidized.There was little dislocation in the mixture zone of the welded joint interface.The dislocation density is high in the area where the recrystallization was little.