TC4/Ti60合金钎焊接头界面组织及力学性能

Interfacial microstructure and mechanical properties of TC4/Ti60 brazed joints

采用TiZrNiCu非晶钎料实现了TC4和Ti60异种钛合金的真空钎焊连接,利用扫描电子显微镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等分析手段研究了钎焊工艺参数对接头界面组织结构及力学性能的影响.结果表明,TC4/TiZrNiCu/Ti60钎焊接头的典型界面结构为:TC4/α-Ti+β-Ti+(Ti,Zr)_2(Ni,Cu)/Ti60.随着钎焊温度升高或保温时间延长,片层状α+β相逐渐填充整条钎缝,(Ti,Zr)_2(Ni,Cu)相含量减少且分布更加均匀.接头室温抗拉强度随钎焊温度或保温时间的增加均先增大后减小,在990℃/10 min钎焊条件下所获接头抗拉强度达到最大为535.3 MPa.断口分析结果表明,断裂位于钎缝中,断裂方式为脆性断裂.

TC4 alloy and Ti60 alloy were brazed using TiZrNiCu amorphous filler alloy. Effects of the brazing process parameters on the interfacial microstructure and mechanical properties of the joints were studied. The interfacial microstructure and possible phases of the joints,as well as the fracture form of fractures, were detected by scanning electron microscope( SEM),energy dispersive spectrometer( EDS) and X-ray diffraction( XRD). The results showed that the typical interfacial microstructure of TC4/Ti60 joint was TC4/α-Ti + β-Ti +( Ti,Zr)_2( Ni,Cu)/Ti60. With increased brazing temperature or prolonged holding time,lamellar α + β microstructure filled the whole brazing seam gradually and( Ti,Zr)_2( Ni,Cu) phase was distributed more evenly. With increasing of brazing temperature or holding time,tensile strength of the joints was first increased and then decreased. The highest tensile strength,535. 3 MPa,was obtained when the joints were brazed at 990 ℃ for 10 min.Fracture analysis indicated that the joints were fractured at brazing seam,which performed as brittle fracture.