Abstract: A first stage rotor blade made of GTD111 alloy in heavy gas turbine after service for 27 000 h was solution treated at 1180 ℃ for 2 h and then argon blowing cooled, the microstructure and mechanical properties of different regions of the blade were compared and analyzed. The results show that dendrite morphology is maintained in the leading edge and middle region of the blade, meanwhile grain boundaries, carbides and γ′ phase are not aged obviously. In the trailing edge of the blade, however, the dendrites disappear, the grain boundaries are coarsened, the carbides degrade obviously, and the γ′ phase is coarsened and rafted. The hardness of trailing edge in the blade as a whole is higher than that of leading edge, the tensile strength of the specimens varying from blade tip to tenon increases first and then decreases on the whole at 25-871 ℃, while that of the specimens at different positions tends to be the same at 982 ℃. For the GTD111 alloy turbine blades after long-term service, the solution treatment at 1180 ℃ cannot completely eliminate the aged microstructure, which is related to the insufficient solution temperature or holding time.

Key words: GTD111 alloy, turbine blade, solution treatment, γ′ phase, carbide, mechanical properties