Abstract:
Successful brazing connection between Al
2O
3 ceramic and TC4 alloy was achieved using Cu foil, producing well-formed joints without obvious defects such as cracks. The effects of brazing temperature and holding time on the microstructure and mechanical properties of Al
2O
3/TC4 joints were systematically investigated, revealing the joint formation mechanism. The results show that the typical interfacial microstructure of Al
2O
3/TC4 joints brazed at 910 ℃ for 10 min was Al
2O
3/Ti
3(Cu,Al)
3O /AlCu
2Ti + (Ti,V)
2(Cu,Al) + Ti(Cu,Al) + Ti
3Cu
4/α-Ti + β-Ti + Ti
2Cu/TC4. With increasing brazing temperature, the Ti
3(Cu,Al)
3O reaction layer first gradually thickened and then remained stable. Due to the gradual overflow of liquid metallic compounds at high temperatures, the overall joint width showed a decreasing trend, while Ti
3Cu
4 formed continuous layers. The shear strength of the joints first increased and then decreased. With prolonged holding time, the joint width gradually decreased and the thickness of Ti
3(Cu,Al)
3O reaction layer increased. The excessively thick reaction layer adversely affected the mechanical properties, causing the shear strength to first increase and then decrease, reaching a maximum value of 102 MPa at 910 ℃ for 10 min holding time.