PSI - Issue 42

6

Author name / Structural Integrity Procedia 00 (2019) 000–000

Petr Dymáček et al. / Procedia Structural Integrity 42 (2022) 1576–1583

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Fig. 6 Comparison of rolled (Specimens I) and rotary swaged (Specimens II) creep performance (a) dependence of time to rupture on stress and (b) dependence of minimum creep rate on stress

Examples of the creep curves of rotary swaged FeAlOY (version A18K), Ni-based superalloy polycrystalline MAR-M947 and single crystals CMSX-4 are shown in Fig. 7. A certain disadvantage of Ni-based alloys is their high primary creep deformation at high stress as shown in the case of CMSX-4 (green curve). On the other side, disadvantage of the FeAlOY is a quite low rupture strain presumably due to limitations of the grain boundaries cohesion at very high temperatures. This should be possible to improve by increasing the grain size, as it is in case of rotary swaged FeAlOY, and/or by optimizing several key factors such as the temperature of milling, additional Y content in the powder, hot consolidation temperatures, and recrystallization temperature.

Fig. 7 Comparison of creep curves from FeAlOY (swaged), and Ni-based superalloy polycrystalline MAR-M947 and singlecrystals CMSX-4.