Microstructure and Mechanical Properties of Brazed B4C-TiB2-SiC-TiC Composite Ceramic Joints
Ag-Cu-Ti and Ag-Cu-Ti+B4C composite brazing alloys were used to braze the B4C-TiB2-SiC-TiC(BTST)composite ceramic.The effects of brazing temperature,holding time,and B4C content on the interfacial microstructure and mechanical properties of the joints were investigated.The results show that Ag-Cu-Ti brazing alloy has a good wettability with BTST and Ti reacts with BTST to form TiC and TiB.The thickness of reaction layer increases with the increase in brazing temperature or holding time,and Ag-Cu eutectic alloy forms in the brazing seam.The bending strength of the joints increases first with the brazing temperature or holding time and then decreases.The addition of B4C into the Ag-Cu-Ti refines the microstructure of brazing seam and reduces the thickness of reaction layer.The maximum bending strength of the joint achieved is 314.2 MPa,when the BTST composite ceramic is brazed at 890 ℃ for 15 min by the Ag-Cu-Ti with 1％B4C(mass fraction).
NETL
NSTL
万方数据
