变形量对Ti2AlNb／Ti60双合金焊接接头组织和力学性能的影响

Effects of Deformation Degree on Microstructure and Mechanical Properties of Welded Joint of Ti_2AlNb/Ti60 Dual Alloys

对经真空电子束焊接的Ti2AlNb/Ti60双合金件进行了不同变形量的近等温锻造及相同的热处理。采用OM观察接头的显微组织,并对其进行室温和高温拉伸试验。结果表明:变形量由20%升至40%,焊缝融合区组织细化、均匀化明显。变形量增至60%,焊缝融合区发生再结晶及晶粒长大。Ti60基体金属随变形量增大,显微组织等轴化趋势明显。20%和60%变形量条件下均有拉伸试样断裂在焊缝融合区。随变形量增大,焊接件强度先降低后升高,断裂在Ti60合金基体的试样塑性有增大趋势,其中断面收缩率值增加明显。

Near isothermal forging with different deformations and the same heat treatment of the electron beam welded joints for Ti2AlNb/Ti60 dual alloys were performed. The microstructures of joints of specimens were examined by OM and tensile tests at room temperature and high temperature were conducted. The results show the following： with the deformations increasing from 20% to 40%, the microstructure in the as-welded fusion zone turns finer and uniform. When deformation increases to 60%, the weld fusion zone produces recrystallization and grain grows. The spheroidization trend of a phase in the Ti60 matrix metal is evident with the increase of deformation. There are tensile specimens fracturing at the as-welded fusion zone under 20% or 60% deformation. With the increase of deformation, the tensile strength of the welded specimens decreases at first and then increases. Plasticity of specimens broken in the Ti60 alloy matrix has increasing trend, in which reduction percetage of area increases significantly.