Ti3SiC2陶瓷与TC4合金钎焊接头微观组织及性能

Interfacial Microstructure and Properties of Ti3SiC2 Ceramic and TC4 Alloy Brazed Joints

摘要:

采用接触反应钎焊,以Ti/Ni/Ti为中间层,实现了Ti3SiC2陶瓷与TC4合金的连接。钎焊接头的典型界面组织为：TC4/α-Ti + β-Ti + Ti2Ni/Ti2Ni + Ti3AlC + Ti5Si3Cx + TiC/Ti3SiC2。随着钎焊温度的升高和保温时间的延长,钎缝宽度增加,Ti2Ni相含量减少。钎焊温度为980 ℃时,大量的Ti2Ni相分布于反应区；连接温度为1000 ℃时,钎焊接头抗剪强度最高,达到82 MPa,断裂主要发生在陶瓷母材处；随着钎焊温度的继续提升,在反应区和TC4合金界面处出现明显孔洞,接头力学性能显著降低。此外,分析了钎焊接头的形成机制。

Abstract:

Ti3SiC2 ceramic and TC4 alloy were successfully joined by a contact-reactive brazing technique using Ti/Ni/Ti interlayers. The results showed that the typical interfacial microstructure of the TC4/Ti3SiC2 joint obtained at 1000 °C for 10 min was TC4/α-Ti + β-Ti + Ti2Ni/Ti2Ni + Ti3AlC + Ti5Si3Cx + TiC/Ti3SiC2. The width of the brazing seam increased and the content of Ti2Ni phase decreased with increased brazing temperature and brazing time. Large amount of Ti2Ni phase distributed in the joint brazed at 980 °C. The joint brazed at 1000 °C for 10 min was well bonded, and the maximum shear strength, 82 MPa, was obtained in corresponding joint and the fracture occurred mainly in the Ti3SiC2 substrate. When the brazing temperature was further elevated, a large number of voids appeared at the interface between the TC4 alloy and the brazing layer, and the shear strength dramatically decreased. Moreover, the formation mechanism of the brazed joints is discussed.