Ti-28Ni钎料真空钎焊TZM合金接头 界面组织与力学性能

TZM alloy was brazed using Ti-28Ni (mass fraction, %) as filler metal at 1040 °C. The effect of holding time on interfacial microstructure and mechanical properties of brazed joints was studied and the typical microstructure of joint was analyzed using SEM and EDS. Results show that the typical interfacial microstructure of the joint is TZM/Ti_ss/δ-Ti₂Ni/Ti_ss/TZM. With the holding time increasing, the width of the brazed seam decreases gradually, the continuous width of Ti_ss layer does not change basically, and the width of middle δ-Ti₂Ni layer decreases to some extent. Meanwhile, the diffusion of TZM into base materials strengthens. When the holding time is relatively short, there is undissolved TZM block in the weld joints, and the base metal can dissolve thoroughly while extending the holding time. The highest average shear strength of the joint is 92.6 MPa when the holding time is 10 min, and the fracture happens at δ-Ti₂Ni layer, which is intergranular brittle fracture.