Serrated yielding in an advanced stainless steel Fe-25Ni-20Cr (wt%)

Published on Mar 28, 2019in Materials Science and Engineering A-structural Materials Properties Microstructure and Processing4.652
· DOI :10.1016/J.MSEA.2019.02.023
Abdullah S. Alomari4
Estimated H-index: 4
(NCSU: North Carolina State University),
Nilesh Kumar18
Estimated H-index: 18
(UA: University of Alabama),
Korukonda L. Murty27
Estimated H-index: 27
(NCSU: North Carolina State University)
Abstract Understanding serrated yielding behavior resulting from dynamic strain aging (DSA) is essential for design and safety considerations. In this work, uniaxial tensile tests were carried out at temperatures ranging from 298 to 1073 K and strain rates 10 −5 – 10 −3 s −1 followed by microstructural examination of Fe-25Ni-20Cr (wt%) austenitic stainless steel (Alloy 709), a candidate structural material for Sodium-cooled Fast Reactors. Serrated yielding was found to occur in this alloy in two temperature regimes; low-temperature serrated flow (LT-SF) from 498 to 648 K and high-temperature serrated flow (HT-SF) from 648 to 973 K (depending on the strain rate) with activation energies of 103 ± 13 kJ/mole and 204 ± 11 kJ/mole respectively. The critical strain for the occurrence of serrations was found to increase with strain rate as an exponential function with exponent (m + β) of 0.78 ± 0.1 and 1.56 ± 0.2 for the LT-SF and HT-SF regimes respectively. Based on the activation energies and m + β values, diffusion of interstitial atoms has been suggested to be responsible for serrated flow in the LT-SF regime while Cr atom migration was inferred to be responsible for DSA in the HT-SF regime. Manifestations of DSA in the Alloy 709 were observed including peaks and/or plateaus in flow stresses along with negative strain rate sensitivity at intermediate temperatures. However, no loss in ductility was observed within DSA regime attributed to the relatively high work hardening rate and strain-hardening exponent. The samples deformed in DSA regime showed planar substructure while equiaxed subgrains formed at higher temperatures. The fraction of low angle grain boundaries after deformation exhibited a valley at intermediate temperatures believed to be another manifestation of the DSA.
📖 Papers frequently viewed together
27 Citations
2 Citations
14 Citations
#1Abdullah S. Alomari (NCSU: North Carolina State University)H-Index: 4
#2Nilesh Kumar (UA: University of Alabama)H-Index: 18
Last. Korukonda L. Murty (NCSU: North Carolina State University)H-Index: 27
view all 3 authors...
Understanding creep properties and microstructural evolution for candidate materials of the next-generation nuclear reactors is essential for design and safety considerations. In this work, creep tests were carried out at temperatures ranging from 973 to 1073 K and stresses 40 to 275 MPa followed by microstructural examinations of a Fe-20Cr-25Ni (mass pct) austenitic stainless steel (Alloy 709), a candidate structural material for the Sodium-cooled Fast Reactors. The apparent stress exponent and...
14 CitationsSource
#1Abdullah S. Alomari (NCSU: North Carolina State University)H-Index: 4
#2Nilesh Kumar (NCSU: North Carolina State University)H-Index: 18
Last. Korukonda L. Murty (NCSU: North Carolina State University)H-Index: 27
view all 3 authors...
Abstract Contrary to the commonly observed embrittlement during dynamic strain aging, we report in this note distinct enhancement in ductility in a Nb-containing and nitrogen stabilized Fe-25(wt%)Ni-20Cr austenitic stainless steel (Alloy 709) at temperatures from 623 K to 873 K at 10−4 s−1 where serrated flow is noted. This observation is rationalized in terms of the influence of strain hardening parameters and strain rate sensitivity on uniform elongation and ductility respectively.
17 CitationsSource
#1Xiangde Bian (CAS: Chinese Academy of Sciences)H-Index: 4
#2Fuping Yuan (CAS: Chinese Academy of Sciences)H-Index: 23
Last. Xiaolei Wu (CAS: Chinese Academy of Sciences)H-Index: 44
view all 3 authors...
Abstract The effects of strain rates on the deformation behaviors of a twinning-induced plasticity (TWIP) steel (Fe23Mn0.6 C) have been investigated using uniaxial continuous tensile tests at different strain rates and strain-rate jump tests, coupled with digital image correlation (DIC) method. A positive instantaneous strain rate sensitivity (ISRS), a negative strain rate sensitivity of work hardening (SRSW) and a negative overall strain rate sensitivity (SRS) have been revealed in the present ...
20 CitationsSource
#1Apu Sarkar (NCSU: North Carolina State University)H-Index: 24
#2Sturat A. Maloy (LANL: Los Alamos National Laboratory)H-Index: 1
Last. Korukonda L. Murty (NCSU: North Carolina State University)H-Index: 27
view all 3 authors...
Abstract Portevin−Le Chatelier (PLC) effect has been observed in HT-9 steel. The present study involves different types of tensile testing to characterize the features of PLC effectin HT-9 steel. Stress serrations observed during tensile tests are analyzed using different statistical analysis techniques to investigate the underlying nature of the effect. Peaked type of stress drop distribution indicated occurrence of type B serrations in the steel. Multiscale entropy analysis of the stress serra...
13 CitationsSource
#1V.D. Vijayanand (RRC: Indira Gandhi Centre for Atomic Research)H-Index: 9
#2K. Laha (RRC: Indira Gandhi Centre for Atomic Research)H-Index: 21
Last. M.D. Mathew (RRC: Indira Gandhi Centre for Atomic Research)H-Index: 26
view all 6 authors...
Abstract The titanium modified 14Cr–15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 × 10 −4 s −1 over...
7 CitationsSource
Abstract Tensile tests were performed at a wide range of strain rates (3.16×10 −5 −3.16×10 −3 s −1 ) and temperatures (300–1123 K) to examine serrated flow behaviour, an important manifestation of dynamic strain ageing (DSA), in type 316L(N) austenitic stainless steel. The steel exhibited distinct low and high temperature serrated flow regimes separated by a retardation bay. Based on the activation energy value of 115 kJ mol −1 , diffusion of interstitial carbon has been suggested to be responsi...
27 CitationsSource
Tensile tests were performed at strain rates ranging from 3.16 × 10−5 to 3.16 × 10−3 s−1 over the temperatures ranging from 300 K to 1123 K (27 °C to 850 °C) to examine the effects of temperature and strain rate on tensile deformation and fracture behavior of nitrogen-alloyed low carbon grade type 316L(N) austenitic stainless steel. The variations of flow stress/strength values, work hardening rate, and tensile ductility with respect to temperature exhibited distinct three temperature regimes. T...
31 CitationsSource
#1K. Linga MurtyH-Index: 18
#2Indrajit CharitH-Index: 24
31 Citations
#1Wade Karlsen (VTT Technical Research Centre of Finland)H-Index: 6
#2Mykola Ivanchenko (TKK: Helsinki University of Technology)H-Index: 6
Last. Hannu Hänninen (TKK: Helsinki University of Technology)H-Index: 26
view all 5 authors...
Abstract Dynamic strain aging (DSA) affects a material’s mechanical behaviour. In the current study, the deformation microstructures of AISI 316 stainless steel specimens were examined after tensile testing at several temperatures both in and out of the DSA-regime (200, 288 and 400 °C), and the effect of straining on free nitrogen evolution at those temperatures was studied by Anelastic Mechanical Loss Spectrometry (Internal Friction). Analysis of the nitrogen-induced Snoek-like peak after strai...
58 CitationsSource
#1L.J. Meng (SJTU: Shanghai Jiao Tong University)H-Index: 3
#2Jian Sun (SJTU: Shanghai Jiao Tong University)H-Index: 3
Last. G.W. Pang (SJTU: Shanghai Jiao Tong University)H-Index: 1
view all 4 authors...
Abstract Serrated flow behavior of the AL6XN austenitic stainless steel has been investigated at different temperatures and strain rates. The results show the serrated flow, peak/plateau in flow stress and negative strain rate sensitivity appearing in tensile deformation of the AL6XN steel at 773–973 K and 3.3 × 10 −5 –3.3 × 10 −3 s −1 (excluding 873 K, 3.3 × 10 −5 s −1 ), suggesting the occurrence of dynamic strain aging (DSA). The activation energy for type-A and -(A + B) serrations was calcul...
33 CitationsSource
Cited By7
#1Abdullah S. Alomari (KACST: King Abdulaziz City for Science and Technology)
#1Abdullah S. Alomari (KACST: King Abdulaziz City for Science and Technology)H-Index: 4
Last. Abdullah S. Alomari (KACST: King Abdulaziz City for Science and Technology)
view all 1 authors...
Austenitic stainless steels are widely employed in various applications due to many desirable properties such as excellent mechanical properties and corrosion/oxidation resistance. Serrated yieldin...
#1Yiyong Zhang (Sichuan University)H-Index: 3
#2Hui WangH-Index: 1
Last. Yuan Wang (SYSU: Sun Yat-sen University)H-Index: 2
view all 6 authors...
The Fe-13Cr-4Al alloy has become a promising candidate material for accident tolerance fuel (ATF) cladding of light-water reactors (LWRs) due to its excellent oxidation resistance to high-temperature water vapor. However, the tensile deformation behavior of the Fe-13Cr-4Al alloy under different strain rates at different temperatures is still unclear. In the present study, the tensile behavior and deformed microstructure of the Fe-13Cr-4Al alloy were investigated at strain rates from 5 × 10–4 to ...
2 CitationsSource
#1Seung-Yong Lee (TITech: Tokyo Institute of Technology)H-Index: 4
#2Chikako TakushimaH-Index: 1
Last. Nobuo Nakada (TITech: Tokyo Institute of Technology)H-Index: 20
view all 4 authors...
Abstract Using digital image correlation (DIC) analysis in an Fe-19Cr-13Ni-0.2C austenitic stainless steel (mass%), the tensile deformation behavior accompanied with the Portevin-LeChatelier (PLC) effect was investigated at high temperatures of 723-823 K under various applied strain rates of 10−4 s−1–5 × 10−3 s−1. With the help of the DIC analysis, the global strain in the gauge part of a tensile specimen and the local strain in a PLC band were precisely measured regardless of the lowering machi...
5 CitationsSource
#1T.D. Porter (Colorado School of Mines)H-Index: 1
#2Zhiyang Wang (ANSTO: Australian Nuclear Science and Technology Organisation)H-Index: 12
Last. Kip O. Findley (Colorado School of Mines)H-Index: 16
view all 6 authors...
Abstract Alloy 709 (20Cr-25Ni-1.5Mo-Nb steel), a candidate structural alloy for Gen IV nuclear reactors, is expected to undergo microstructural evolution during long-term service at elevated temperatures, which in turn affects the mechanical behavior through changing contributions from precipitate and solute strengthening. For safe reactor design, it is important to understand how microstructural evolution and mechanical behavior differ between long-term service and accelerated laboratory tests,...
#1Amrita Lall (NCSU: North Carolina State University)H-Index: 2
#2Paul Bowen (University of Birmingham)H-Index: 31
Last. Afsaneh Rabiei (NCSU: North Carolina State University)H-Index: 27
view all 3 authors...
Abstract Alloy 709 is a novel austenitic stainless steel with high temperature creep strength, weldability, and corrosion resistance. These properties make the material suitable for applications in the structure of next-generation nuclear power plants. Enduring high temperatures for an extended period of time in the harsh environments of a nuclear power plant results in thermal aging of the material. Therefore, it is imperative to study the effect of thermal aging on the microstructure and mecha...
#1Yuchen Zhao (NCSU: North Carolina State University)H-Index: 1
#2Mahmut N. Cinbiz (INL: Idaho National Laboratory)H-Index: 5
Last. Djamel Kaoumi (NCSU: North Carolina State University)H-Index: 13
view all 5 authors...
Abstract Uniaxial tensile tests were done on Fe-25Ni-20Cr Austenitic Stainless Steel (Alloy 709) along with in-situ synchrotron measurement at different temperatures (25 °C, 500 °C, 700 °C and 900 °C). The X-Ray diffraction data was collected in-situ in order to follow the phases present as well as to derive the dislocation density as a function of strain through peak broadening analysis based on the modified Williamson-Hall method and see how trends are affected as a function of temperature. Th...
#1Martin Taylor (UIdaho: University of Idaho)H-Index: 2
#2Jose Ramirez (UIdaho: University of Idaho)H-Index: 2
Last. Michael V. Glazoff (INL: Idaho National Laboratory)H-Index: 13
view all 6 authors...
Abstract Alloy 709 is an austenitic stainless steel with potential for structural applications in advanced nuclear reactors. In this study, creep tests on Alloy 709 specimens were performed at a temperature of 700 °C under applied stresses in the range of 125–250 MPa. The alloy exhibited a brief primary, insignificant secondary and prolonged tertiary creep stages. A Norton stress exponent ( n ) of ∼6 was obtained from the creep plots. Microstructural analyses were carried out for both as-receive...
2 CitationsSource