不同钎料真空钎焊的TC4/YG8接头组织与力学性能研究

Microstructure and Mechanical Properties of TC4/YG8 Joint by Vaccum Brazing with Different Filler Metals

分别采用Cu69Ni Si B、Ni82Cr Si B及Ag94Al Mn三种钎料对TC4钛合金和YG8硬质合金进行真空钎焊试验。采用润湿性试验、金相显微镜、显微硬度计、扫描电子显微镜等测试手段,分别对这三种钎焊接头的微观组织、显微硬度等进行了对比分析。结果证明：Cu基钎料和Ni基钎料对硬质合金的润湿性能均较差,在其钎焊接头中均出现裂纹、脆性相;采用Ag基钎料进行钎焊,钎焊温度为920℃,保温时间为20 min时,Ag基钎料与钛合金、硬质合金的界面结合良好,无微裂纹,钎缝组织为Ag基组织,硬质合金母材Co、W元素和钛合金母材Ti、V元素向钎缝内扩散甚少,母材不发生溶蚀。

The vaccum brazing tests of TC4 titanium alloy and YG8 hard metal were carried out with Cu69 Ni Si B,Ni82 Cr Si B and Ag94 Al Mn filler metals, respectively. The microstructure, microhardness of the three brazing joints were analyzed by wettability test, metallographic microscope, microhardness tester and scaning electron microscope, etc. The results show that the wetting properties of Cu-based solder and Ni-based solder on the hard metal are poor, and cracks and brittle phases appear in the two brazed joints. When the Ag-based solder is used to braze TC4 and YG8 under brazing temperature of 920 ℃ and holding time of 20 minutes, the interfaces of Ag-based brazing alloy with the titanium alloy and hard metal are good, no microcrack is found, and the microstructure of the brazing seam is Ag-based structure, and the Co, W in the hard metal and Ti, V in the titanium alloy diffuses a little into the brazing seam, and the base metals does not dissolve.