Effect of Strain Range on High Temperature Creep-Fatigue Behaviour of Fe-25Ni-20Cr (wt.%) Austenitic Stainless Steel (Alloy 709)

Alsmadi, Zeinab Y.; Murty, K. Linga

doi:10.1080/09603409.2020.1859310

Cited by 4 publications

(5 citation statements)

References 41 publications

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“…As the hold time further increased, the number of cycles to failure did not exhibit a significant decrease, indicating that longer hold times did not impose further damage. This saturation behavior has also been observed in Alloy 709 under strain-controlled conditions [ 10 , 14 , 19 ].…”

Section: Resultssupporting

confidence: 66%

“…Various studies have reported softening behavior in Alloy 709 when tested at 750 °C or beyond, where detailed microstructural analyses have been performed [ 7 , 9 , 14 , 23 , 29 , 30 ]. Zhao et al studied the tensile behavior and microstructure evolution of Alloy 709 from room temperature to 900 °C using in situ x-ray diffraction and found that material hardening dominated up to 500 °C, where dynamic strain aging started to occur [ 29 ].…”

Section: Resultsmentioning

confidence: 99%

“…One of the newly developed advanced austenitic stainless steels is Alloy 709 (belongs to the family of Fe-25Ni-20Cr (wt. %) stainless steels), which is a strong candidate structural material for next-generation nuclear reactors [ 13 , 14 ]. Preliminary investigations have shown that Alloy 709 is compatible with a sodium-rich environment and thermally stable with good high-temperature strength due to the existence of niobium (Nb) [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

“…However, understanding micromechanisms governing high-temperature creep–fatigue behavior of this alloy is not well-established. Few authors have carried out creep–fatigue tests in order to understand the response of Alloy 709 at elevated temperatures [ 10 , 14 , 17 , 18 , 19 ]. Alsmadi et al [ 10 , 14 , 19 ] have performed high-temperature creep–fatigue tests in strain-controlled mode under different experimental conditions to study the effect of tensile hold time (0, 60, 600, 1800, and 3600 s), temperature (650 and 750 °C), and strain range (0.6–1.2%) on the creep–fatigue life of Alloy 709.…”

Section: Introductionmentioning

confidence: 99%

“…Few authors have carried out creep–fatigue tests in order to understand the response of Alloy 709 at elevated temperatures [ 10 , 14 , 17 , 18 , 19 ]. Alsmadi et al [ 10 , 14 , 19 ] have performed high-temperature creep–fatigue tests in strain-controlled mode under different experimental conditions to study the effect of tensile hold time (0, 60, 600, 1800, and 3600 s), temperature (650 and 750 °C), and strain range (0.6–1.2%) on the creep–fatigue life of Alloy 709. The creep–fatigue life of the Alloy 709 was shown to decrease with increasing tensile hold time, temperature, and strain range.…”

Section: Introductionmentioning

confidence: 99%

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Stress-Controlled Creep–Fatigue of an Advanced Austenitic Stainless Steel at Elevated Temperatures

et al. 2022

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Creep–fatigue interaction occurs in many structural components of high-temperature systems operating under cyclic and steady-state service conditions, such as in nuclear power plants, aerospace, naval, and other industrial applications. Thus, understanding micromechanisms governing high-temperature creep–fatigue behavior is essential for safety and design considerations. In this work, stress-controlled creep–fatigue tests of advanced austenitic stainless steel (Alloy 709) were performed at a 400 MPa stress range and 750 °C with tensile hold times of 0, 60, 600, 1800, and 3600 s, followed by microstructural examinations. The creep–fatigue lifetime of the Alloy 709 was found to decrease with increasing hold time until reaching a saturation level where the number of cycles to failure did not exhibit a significant decrease. Softening behavior was observed at the beginning of the test, possibly due to the recovery of entangled dislocations and de-twining. In addition, hysteresis loops showed ratcheting behavior, although the mean stress was zero during creep–fatigue cycling, which was attributed to activity of partial dislocations. Microstructural examination of the fracture surfaces showed that fatigue failure dominated at small hold times where the cracks initiated at the surface of the sample. Larger creep cracks were found for longer hold times with a lower probability of dimpled cavities, indicating the dominance of creep deformation. The results were compared with other commonly used stainless steels, and plausible reasons for the observed responses were described.

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Section: Resultssupporting

confidence: 66%