Study on Microstructure and Properties of Al₂O₃/1Cr18Ni9Ti Vacuum Brazing Joint with CuSnTi Solder

In order to study the microstructure and properties of ceramics and stainless steel welding joint,the vacuum brazing tests between Al₂O₃ and 1Cr18Ni9Ti stainless steel filled with Cu Sn Ti solder were studied,and the effects of temperature,holding time and pressure on the microstructure and properties of the joint were explored.The results show that Ti diffuses to the interface areas at both sides,TiFe compound layer is formed at the interface of Al₂O₃ and TiFe₂ compound layer is formed at the interface of stainless steel during the brazing process.The brazing joint is mainly composed of Cu solid solution,eutectic structure of Cu₈₁Sn₂₂and bulk TiFe phase.Due to the large welding stress caused by the difference of thermal expansion coefficient between Al₂O₃ and 1Cr18Ni9Ti,cracks are close to the interface region at the side of Al₂O₃ in all joints,and all fractures occur at the position in shearing tests.The shear strength of the joint reaches the maximum value of 99.79MPa under the conditions of 940℃,30 min and 5 MPa.