High Temperature Creep Properties and Microstructure of Ti-Al-Zr-Mo-Nb-Sn-Si Cast Titanium Alloy

The creep properties and microstructures of Ti-Al-Zr-Mo-Nb-Sn-Si cast titanium alloy at 600~750 ℃ were studied. The results showed that the creep residual elongations were less than 3% at 750 ℃/180 MPa/0.5 h and less than 0.4% at 600 ℃/400 MPa/0.5 h. The time before creep ruptures were more than 2 h and more than 14 h, respectively. The cast titanium aiioy had good creep resistance. There were fine particles in the high temperature creep fracture surface. After creep, the microstructure changed little in the plastic deformation zone, showing widmannstatten structure, and some grain boundaries disappeared and α lamellae became wider. After high temperature creep, dislocations increased obviously and entangled with precipitates.