一种钛基钎料钎焊TiAl/GH536的接头界面组织及性能

采用Ti-Zr-Fe-Cu-Ni-Co-Mo钎料实现了TiAl合金与GH536合金的有效钎焊连接. 运用SEM，EDS，XRD等手段对钎焊接头的界面组织进行了分析，并检测了钎焊接头的抗剪强度. 结果表明，钎焊接头的典型界面组织由TiAl合金一侧到GH536合金一侧包括Ⅰ层(Ti₃Al + TiAl)、Ⅱ层(Al₃NiTi₂)、Ⅲ层(以AlNi₂Ti为主，并含有富铬(Cr,Ni,Fe)_SS、富镍(Cr,Ni,Fe)_SS和(Ni)_SS + TiNi₃)和Ⅳ层(以富铬(Cr,Ni,Fe)_SS为主，并含有富镍(Cr,Ni,Fe)_SS，AlNi₂Ti和(Ni)_SS + TiNi₃). 当钎焊时间为10 min时，在1 110 ~ 1 170 ℃的钎焊温度范围内，随着钎焊温度的升高，钎焊接头的抗剪强度先升高后降低. 钎焊温度对原子扩散和金属间化合物的形成有较大的影响，较低或较高的温度都会导致接头强度偏低. 1 150 ℃钎焊10 min获得的接头抗剪强度最高，为183 MPa，接头主要断裂在Ⅱ层.

Microstructure and properties of brazing joints with a Ti-based filler of TiAl/GH536 alloy

Vacuum brazing of TiAl alloy and GH536 alloy with Ti-Zr-Fe-Cu-Ni-Co-Mo filler as interlayer was investigated. The microstructure of the brazed joints was characterized by employing SEM, EDS and XRD, and shear strength of the joints was analyzed in detail. Results show that the typical microstructure of the joint is given below: TiAl/layer I /layer II /layer III /layer IV /GH536. Layer I is mainly composed of Ti₃Al, in which some TiAl phases are embedded. Layer II is constituted by Al₃NiTi₂. Layer III mainly contains AlNi₂Ti, the other phases are Cr-rich (Cr, Ni, Fe)_SS, Ni-rich (Cr, Ni, Fe)_SS and (Ni)_SS + TiNi₃. In Layer IV, there are still Cr-rich (Cr, Ni, Fe)_SS, but a small number of Ni-rich (Cr, Ni, Fe)_SS, AlNi₂Ti and (Ni)_SS + TiNi₃ can be observed. The shear strength first increases and then decreases in the brazing temperature range of 1 110 ~ 1 170 °C for 10 min. The diffusion of atoms and the formation of intermetallic compounds are closely related to the brazing temperature. Lower or higher brazing temperature will lead to lower joint strength. It obtains a maximum value of 183 MPa at temperature of 1 150 °C with a holding time of 10 min, and the joints are mainly fractured at layer II.