Thermal-Mechanical Fatigue Property of Ni-Base Single Crystal Superalloys TMS-82+ and TMS-75

Abstract

The effect of hold time (th) on the thermal-mechanical fatigue property (TMF) of two nickel-base single crystal superalloys TMS-82+ and TMS-75, which are second- and third-generation single crystals, respectively, was investigated. Cycles to failure for both alloys decreased drastically with the increase in the hold time. The TMS-75 showed a longer life than the TMS-82+ at th = 0. The TMS-82+ showed a longer life than the TMS-75 at t h ≠ 0, which could be attributed to the higher tensile strength at 400°C and higher stress relaxation resistance at 900°C in the TMS-82+. From microstructural studies, a slightly rafted γ/γ′ structure was observed in the TMS-82+ for TMF with a hold time. This work indicates that the TMS-82+ is appropriate to be served in gas turbine engines under specific conditions such as electric power generation.