Creep Behavior and Microstructural Evolution of a Fe-20Cr-25Ni (Mass Percent) Austenitic Stainless Steel (Alloy 709) at Elevated Temperatures

Alomari, Abdullah S.; Kumar, N.; Murty, K. Linga

doi:10.1007/s11661-018-5044-y

Cited by 26 publications

(15 citation statements)

References 40 publications

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“…However, the creep curve at 3600 s hold time entered the steady-state regime with an evaluated steady-state strain rate of 6.1 × 10 −5 s −1 . The values of strain rates obtained at all examined hold times were found to be very close to those observed in creep tests where a value of minimum creep rate of 7.51 × 10 −7 s −1 was observed at the same examined temperature (750 °C) and applied stress (200 MPa) [ 23 ].…”

Section: Resultssupporting

confidence: 65%

“…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%

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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: 65%

Section: Resultsmentioning

confidence: 99%

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

et al. 2022

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“…The value of C MG ∼ 0.04 in P91 steel has been reported by researchers [1]. For materials that exhibit a shorter secondary creep deformation regime and a larger tertiary creep deformation regime, the modified MG relationship has been proposed as [1,[26][27][28][29][30][31][32]:…”

Section: Creep Rate-rupture Life Relationshipsmentioning

confidence: 70%

“…Both P91 and P91BN steels obeyed the MG and modified MG relationships. Values of C MMG ranging from 0.1 to 0.83 have been reported for various ferrous and non-ferrous alloys [32]. Plots of variation of time to the onset of tertiary creep (t ot ) (initiation of accelerated creep rate regime) with t r for P91 and P91BN steels are shown in Figure 13, and this variation followed a linear relationship as t ot = f•t r , where f is a constant.…”

Section: Creep Rate-rupture Life Relationshipsmentioning

confidence: 91%

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Creep deformation and rupture behaviour of boron-added P91 Steel

Sakthivel

Sasikala

Rao

et al. 2021

Materials Science and Technology

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Creep deformation and rupture behaviour of P91 and boron-added P91BN steels were investigated over the stress range of 100–350 MPa at 823, 873 and 923 K. The time spent in each creep regime was significantly higher in P91BN steel as compared to P91 steel. The reduction in the minimum creep rate in P91BN steel about one to two orders of magnitude was observed than that in the P91 steel. An addition of boron (0.006 wt-%) with controlled nitrogen content (0.011 wt-%) in P91BN led to better creep rupture strength than the P91 steel. Using the Larson–Miller parametric method, creep rupture strength evaluated at 873 K for 105 h life was about 33% enhancement in the case of P91BN steel than P91 steel.

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