• The creep resistance of HT2 exceeds that of HT3, highlighting a significant precipitation strengthening effect of α2 phase.
• At temperatures and stresses lower than or equal to 570 °C and 200 MPa, respectively, the creep resistance of HT1 is close to that of HT3, suggesting that silicide precipitated before creep attenuates the strengthening of creep deformation caused by the coarsening of αs phase.
• At 600 °C and 250 MPa, the creep resistance of HT1 is significantly higher than that of HT3, indicating that when the dynamic precipitation of silicide in HT1 is adequate, it also resists the creep deformation of the alloy.
• The stress exponent for HT1, HT2 and HT3 ranges 1.7−1.9 (550 °C) and 3.7−4.4 (600 °C), indicating that the amount of silicide and α2 phase doesn’t affect the creep mechanism.