Brazing Bonding Process And Interface Behavior Of C/C Composite And TIB_w-TC4 Alloy

Due to its low density, high strength, high temperature resistance, ablation resistance, flushing resistance and so on, C/C composite has wide prospected applications in aerospace and automobile fields. TiBBw-TC4 is a kind of Ti alloy reinfored by short fibers TiB and has such characteristics as low density, high temperature resistance, oxidization resistance and excellent over-rall properties. The joining of two materials can realize dominance complementation. In this paper, TiZrNiCu amorphous foil and home-made brazing alloy Cu-Ni+(TiB₂/SiC) are used to realize the successful joining of C/C composite and TiBwB-TC4 alloy. The interfacial structure of the joint is confirmed, the interfacial joining mechanism is studied and the influence of craft on the joint's structure is analyzed. Mechanical behavior of the joint in both room temperature and high temperature is tested, and the cracking routes of the joints are determined. Through the analytic result of the brazing joint with the TiZrNiCu foil, when T=1173K, t=10min, the interfacial microstructure of the brazing joints was C/C composite/TiC+ZrC/(Ti,Zr)2(Cu,Ni)/[Ti(s.s)+(Ti,Zr)2(Cu,Ni)]/TiBBw-TC4. The shear strength was tested to evaluate the mechanical property of the joints. The results showed the maximum shear strength was 13.6MPa, which was achieved when the brazing temperature was 1173K and holding time was 10min. And at this time, the fracture took place in the TiC layer adjacent to C/C composite. Using the home-made solder of Cu-Ni+(TiB₂/SiC), when T=1223K, t=10min, the interfacial structure of C/C composite/Cu-Ni+TiB₂/TiBw-TC4 alloy was C/C composite/TiC/Ti(Cu,Al)2/Ti2Cu+TiNi+TiCu+TiB/[Ti2(Cu,Ni)+Ti(s.s)]/TiBBw-TC4. alloy. the interfacial structure of C/C composite/Cu-Ni+SiC/TiBwB-TC4 alloy was C/Ccomposite/TiC/Ti(Cu,Al)2/Ti2Cu+TiNi+TiCu+[Ti3SiC2+TiSi2]/[Ti2(Cu,Ni)+Ti(s.s)]/TiBw-TC4. The reinforcement particles TiBB2/SiC were added, reject the growth of the intermetallics, refine the structure of the welded seam. The shear strength was tested to evaluate the mechanical property of the joints. With the parameters increasing, the shear strength increased first and then decreased. When T=1223K, t=10min, using the solder Cu-Ni+TiBB2, The shear strength at room-temperature was 18.5MPa. the shear strength at 400°C was 34.5MPa. Using the solder Cu-Ni+SiC, The shear strength at room-temperature was 22.5MPa. the shear strength at 400°C was 35.4MPa. The fracture of room-temperature joints took place in the TiC/Ti(Cu,Al)2 layer adjacent to C/C composite, while at the high temperature, the fracture took place in the Ti2Cu+TiNi+TiCu layer or Ti2Cu+Ti2Ni layer. Through thermodynamics and formating process of the interface, disclosure the mechanics of the interface connecting with using the solders TiZrNiCu and Cu-Ni+(TiB₂/SiC).