Mechanical properties of Haynes alloy 188 after 22,500 hours of exposure to LiF-22CaF[sub 2] and vacuum at 1,093 K

As a continuation of a study of a space-based thermal energy storage system centered on a LiF-CaF[sub 2] eutectic salt contained by Haynes alloy 188, this Co-base superalloy was subjected to molten salt, its vapor, and vacuum for 22,500 h at 1,093 K. Samples from all three exposure conditions were tensile tested between 77 to 1,200 K; in addition, vacuum and molten-salt exposed specimens were vacuum creep rupture tested at 1,050 K. Comparison of these mechanical properties with those measured for the as-received alloy reveals no evidence for degradation beyond that ascribed to sample thermal aging of Haynes alloy 188. This behavior is identical to the 10,000 h results; hence, Haynes alloy 188 is a suitable containment material for an eutectic LiF-CaF[sub 2] thermal energy storage salt.