PSI - Issue 42

Petr Dymáček et al. / Procedia Structural Integrity 42 (2022) 1576–1583 Author name / Structural Integrity Procedia 00 (2019) 000–000

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The creep tests of older versions of FeAlOY with 14% Cr and without Cr are shown in Fig. 8. For more details see Svoboda et al. 2020. Different hot consolidation temperatures 900 or 930 °C were compared with small effect. The creep curves shown in Fig. 8d exhibit short primary and part of secondary creep stage with sudden rupture without any tertiary creep stage. The creep strain must be divided by about 2 due to creep of grips and pull rods as mentioned in paragraph 2.2.

Fig. 8 Older results of creep tests at 1100 °C of the FeAlOY with different chemical compositions and hot consolidated by rolling at different temperatures (in brackets). (a) time to rupture vs stress dependence (b) creep rate vs stress dependence (c) ductility vs applied stress dependence (d) examples of creep curves. Note: The creep strain must be divided by about 2 due to creep of grips and pull rods. The addition of metallic Y to the powder seems to play an important role by catching excess oxygen from the powder surfaces and forming additional Y 2 O 3 precipitates. In the study by Svoboda et al. (2022) an optimum value of Y was determined for rolled FeAlOY with Cr at about 1.3% and without Cr at about 1%. A clear influence of additional Y on the grain size and morphology after secondary recrystallization was documented.

Fig. 9 Ultimate tensile strengths at 1000 °C of Fe-10Al-4Y 2 O 3 and Fe-10Al-4Cr-4Y 2 O 3 (rolled FeAlOY) specimens with addition of different amounts of metallic Y. Note: several values coincide, so are not visible.