Tensile properties of Haynes alloy 230 and Inconel 617 after long exposures to LiF-22CaF[sub 2] and vacuum at 1,093 K

As a part of a study of a space-based thermal energy storage system utilizing the latent heat of fusion of the eutectic salt LiF-20CaF[sub 2] (mole%), the two wrought Ni-base superalloys Haynes alloy 230 and Inconel 617 were subjected to molten salt, its vapor, and vacuum for periods as long as 10,000 h at 1,093 K. Following exposure, the microstructures were characterized, and samples from each superalloy were tensile tested between 77 and 1,200 K. Neither the structure nor mechanical properties revealed evidence for additional degradation due to exposures to the salt. Although some loss in tensile properties was noted, particularly at 77 K, this reduction could be ascribed to the influence of simple aging at 1,093 K.