Effect of Massive MC Carbide with Niobium on High-Temperature Properties of LF2 Alloy

The high-temperature tensile test of LF2 alloy at 700 ℃ after long-time aging at 700 ℃ and the tensile creep test of LF2 alloy at 725 ℃ after solid solution and aging were carried out, and the effect of MC carbide with niobium on fracture mechanism of LF2 alloy was mainly analyzed. The results show that cracks initiated around massive carbide with niobium at high-temperature tensile state, and then propagated and fractured at last. Cracks initiated around massive carbide with niobium at high-temperature creep state, and then propagated along grain boundaries until fractured, and it exhibited the characteristic of intergranular fracture. Massive carbide with niobium was the main factor of affecting high-temperature properties of LF2 alloy.