电子束焊接线能量对Ti-24Al-15Nb-1Mo合金接头组织性能的影响

Effect of EBW Line Energy on Microstructure and Mechanical Properties of Ti-24Al-15Nb-1Mo Joint

研究了电子束焊接不同线能量对合金接头组织、性能的影响机理,确定了具有比较满意的塑性和韧性的接头性能的电子束工艺参数选择窗口。结果表明,焊态下焊缝组织为残留β/B2相和包括次生α2相、O相以及ω相在内的β转变组织;焊接线能量增加,焊缝晶粒粗化,B2相的减少、初生α2的消失和ω相的产生以及β转变组织中次生的α2/O相集束增大并促进裂纹扩展是接头强度降低和脆变的主要原因。

The effect of electron beam welding （EBW） heat input factors on Ti-24Al-15Nb-1 Mo （at%） joint microstructure and mechanical properties was investigated. The suitable EBW parameter windows are then determined to attain satisfactory joint ductility and impact toughness. It is shown that the as-welded joint microstructure was composed of a small amount of retained β/B2 phases and β- transformed microstructures including secondary α2 , some O phase and ω phase. It is indicated that the coarsening grain size , the existence of retained 3 structure, reducing B2 phase and disappearance prime α2 phase and O phase, as well as formation of ω phase together with the growing α2/O colony as the heat input increased in welding are the main reasons for the decrease of the strength and the ductility of the joints.