Effect of holding time on interfacial evolution and mechanical strength of wide-gap brazed K417G superalloy joints
摘要
K417G superalloy is widely applied in gas turbine components such as blades, vanes, and nozzles. In this study, wide-gap brazing of K417G superalloy is investigated using BNi-5 filler alloy. The brazing experiment is conducted at 1150 °C for different holding times with the fixed gap of 0.2 mm. For the joints brazed for 15 min, the brazing seam mainly consists of γ/γ’ phase, Ni2Si and TiC phase. The average tensile strength tested at 950 °C is 401 MPa. As the holding time increased, the excessive element diffusion phenomenon is observed. Hence, Ni2Si intermetallic phases gradually become embedded in the additive alloy particles. The interfacial evolution and fracture behavior are discussed.