钎焊工艺参数对TC4钛合金钎焊接头组织及性能的影响

Effects of Brazing Parameters on Microstructures and Mechanical Properties of TC4 Brazed Joints

在钎焊温度为780~900℃,钎焊时间为2~30 min的条件下,采用Ag-28Cu钎料对TC4钛合金进行了真空钎焊试验。利用金相显微镜、扫描电镜及能谱仪对接头微观组织进行了研究。结果表明,接头形成3个反应区:扩散区Ti2Cu+Ti(s.s)、界面反应区Ti2Cu/TiCu化合物以及钎缝中心区的Ag(s.s)+Cu(s.s)。随着钎焊温度的提高和保温时间的延长,扩散区及界面层的厚度增加,但过高的工艺参数会导致钎料流失从而使钎缝宽度降低。在钎焊温度为820℃,保温时间为10 min时,钎焊接头的抗剪强度最高,为121 MPa。

TC4 was vacuum brazed using Ag-28Cu filler metal at 780-900℃ for 2-30 min. The microstructures were investigated by optical microscope, scanning electron microscopy, electron energy spectrum. The results show that the brazed joint can be divided into three zones: diffusion zone(Ti2Cu+Ti(s.s)), interfacial reaction zone(Ti2Cu/TiCu) and central zone(Ag(s.s)+Cu(s.s)).With the increase of brazing temperature and holding time, the thicknesses of diffusion zone and interfacial reaction zone increase. However, too high technological parameters will lead to loss of solder and decrease of width of brazing seam. The maximum shear strength of the brazed joint is 121 MPa at brazing temperature of 820℃ for 10 min.