真空搭接钎焊TC4钛合金接头的组织及力学性能

Microstructure and mechanical properties of vacuum lap brazed joint of TC4 titanium alloy

采用B-Ti57CuZrNi钎料真空搭接钎焊TC4钛合金板材,研究了钎焊温度和时间对焊接接头组织和力学性能的影响。结果表明,钎焊接头的微观组织主要由B-Ti57CuZrNi钎料凝固组织及扩散过渡层针状组织组成。随焊接温度升高,焊缝和针状组织层宽度增加,凝固组织减少。随焊接时间增加,焊缝凝固组织宽度降低,焊缝宽度和针状组织层宽度均增加。钎焊温度低于930℃时会导致室温拉伸性能降低,910℃时的最大断裂力仅为5.1~5.5kN。钎焊时间高于45min时会导致室温拉伸性能降低。从钎焊接头力学性能考虑,钎焊温度930~950℃、钎焊时间不超过45min为宜。

TC4 titanium alloy plate was vacuum lap brazed with B-Ti57CuZrNi solder,and the effects of brazing temperature and time on microstructure and mechanical properties of the brazed joint were studied.The results show that the microstructure of brazed joint is mainly composed of solidification microstructure of B-Ti57CuZrNi solder and needle-like microstructure of diffusion transition layer.With the increase of brazing temperature,the width of weld and needle-like layer increases,and the width of solidification microstructure decreases.With the increase of brazing time,the width of solidification microstructure decreases,and the width of weld and needle-like layer increases.When the brazing temperature below 930 ℃,the room temperature tensile properties will decrease as the maximum breaking force at 910℃is only 5.1-5.5 kN.When the brazing time is longer than 45 min,the room temperature tensile properties will also decrease.Considering the mechanical properties of the brazed joint,the brazing temperature of 930-950℃and brazing time of less than 45 min are suitable.