Abstract:
Al
2O
3 and TC4 alloy were brazed with Cu+B brazing filler at 890-970℃ for 10 min and at 930℃ for 0-30 min, respectively.The microstructure and mechanical properties of the resultant joints were investigated with SEM, EDS and shear testing machine.The results indicated that with the increasing of brazing temperature and holding time, the thickness of Ti
4(Cu, Al) 2O layer increased, next to which continuous and thick Ti
2(Cu, Al) existed, and the amounts of Ti
2(Cu, Al) and Ti+Ti
2(Cu, Al) increased.The size and distribution range of Ti+Ti
2(Cu, Al) also increased, which migrated to the TC4 alloy side.The hypereutectoid regions widened near the TC4 alloy.Below 950℃, the TiB whiskers were mainly dispersed on AlCu
2Ti in grain boundary of Ti
2Cu.While above 950℃, the AlCu
2Ti gradually disappeared, and TiB whiskers were mainly distributed on Ti
2Cu.When the holding time was 10 min and brazing temperature was 950℃, the maximal joint shear strength was 96 MPa.While the holding time was 20 min and brazing temperature was 930℃, and the maximal joint shear strength was 83 MPa.