The effect of ultrafine-grained size on creep behaviour was investigated in P92 steel. Ultrafine-grained steel was prepared by one revolution of high-pressure torsion at room temperature. Creep tensile tests were performed at 873 K under the initially-applied stress range between 50 and 160 MPa. The microstructure was investigated using transmission electron microscopy and scanning electron microscopy equipped with an electron-back scatter detector. It was found that ultrafine-grained steel exhibits significantly faster minimum creep rates, and there was a decrease in the value of the stress exponent in comparison with coarse-grained P92 steel. Creep results also showed an abrupt decrease in the creep rate over time during the primary stage. The abrupt deceleration of the creep rate during the primary stage was shifted, with decreasing applied stress with longer creep times. The change in the decline of the creep rate during the primary stage was probably related to the enhanced precipitation of the Laves phase in the ultrafine-grained microstructure.

Department of Materials Science and Engineering Faculty of Engineering Kyushu University Fukuoka 819 0395 Japan

Institute of Physics of Materials Academy of Sciences of the Czech Republic Zizkova 22 616 62 Brno Czech Republic

UJP PRAHA a s Nad Kamínkou 1345 156 10 Praha Zbraslav Czech Republic

Zobrazit více v PubMed

Valiev R.Z., Islamgaliev R.K., Alexandrov I.V. Bulk nanostructured materials from severe plastic materials. Prog. Mater. Sci. 2000;45:103–189. doi: 10.1016/S0079-6425(99)00007-9. DOI

Klimova M., Zherebtsov S., Stepanov N., Salishchev G., Haase C., Molodov D.A. Microstructure and texture evolution of a high manganese TWIP steel during cryo-rolling. Mater. Charact. 2017;132:20–30. doi: 10.1016/j.matchar.2017.07.043. DOI

Edalati K., Horita Z., Yagi S., Matsubara E. Allotropic phase transformation of pure zirconium by high-pressure torsion. Mater. Sci. Eng. A. 2009;523:277–281. doi: 10.1016/j.msea.2009.07.029. DOI

Edalati K., Matsubara E., Horita Z. Processing pure Ti by high-pressure torsion in wide ranges of pressures and strain. Metall. Mater. Trans. A. 2009;40:2079–2086. doi: 10.1007/s11661-009-9890-5. DOI

Meng F.Q., Tsuchiya K., Yokoyama Y. Crystalline to amorphous transformation in Zr-Cu-Al alloys induced by high pressure torsion. Intermetallics. 2013;37:52–58. doi: 10.1016/j.intermet.2013.01.021. DOI

Edalati K., Horita Z. A review on high-pressure torsion (HPT) from 1935 to 1988. Mater. Sci. Eng. A. 2016;652:325–352. doi: 10.1016/j.msea.2015.11.074. DOI

Valiev R.Z., Langdon T.G. Principles of equal-channel angular pressing as a processing tool for grain refinement. Prog. Mater. Sci. 2006;51:881–981. doi: 10.1016/j.pmatsci.2006.02.003. DOI

Fujioka T., Horita Z. Development of high-pressure sliding process for microstructural refinement of rectangular metallic sheets. Mater. Trans. 2009;50:930–933. doi: 10.2320/matertrans.MRP2008445. DOI

Zherebtsov S., Kudryavtsev E., Kostjuchenko S., Malysheva S., Salishchev G. Strength and ductility-related properties of ultrafine grained two-phase titanium alloy produced by warm multiaxial forging. Mater. Sci. Eng. A. 2012;536:190–196. doi: 10.1016/j.msea.2011.12.102. DOI

Saito Y., Utsunomiya H., Tsuji N., Sakai T. Novel ultra-high straining process for bulk materials—Development of the accumulative roll-bonding (ARB) proces. Acta Mater. 1999;47:579–583. doi: 10.1016/S1359-6454(98)00365-6. DOI

Huang Y., Sabbaghianrad S., Almazrouee A.I., Al-Fadhalah K.J., Alhajeri S.N., Langdon T.G. The significance of self-annealing at room temperature in high-purity copper processed by high-pressure torsion. Mater. Sci. Eng. A. 2016;656:55–66. doi: 10.1016/j.msea.2016.01.027. DOI

Edalati K., Uehiro R., Fujiwara K., Ikeda Y., Lia H.-W., Sauvage X., Valiev R.Z., Akiba E., Tanaka I., Horita Z. Ultra-severe plastic deformation: Evolution of microstructure, phase transformation and hardness in immiscible magnesium-based systems. Mater. Sci. Eng. A. 2017;701:158–166. doi: 10.1016/j.msea.2017.06.076. DOI

Valiev R.Z., Pushin V.G., Gunderov D.G., Popov A.G. The use of severe deformations for preparing bulk nanocrystalline materials from amorphous alloys. Dokl. Phys. 2004;49:519–521. doi: 10.1134/1.1810577. DOI

Edalati K., Horita Z. Application of high-pressure torsion for consolidation of ceramic powders. Scr. Mater. 2010;63:174–177. doi: 10.1016/j.scriptamat.2010.03.048. DOI

Straumal B.B., Kilmametov A.R., Korneva A., Mazilkin A.A., Straumal P.B., Zie P., Baretzky B. Phase transitions in Cu-based alloys under high pressure torsion. J. Alloys Comp. 2017;707:20–26. doi: 10.1016/j.jallcom.2016.12.057. DOI

Kumar P., Kawasaki M., Langdon T.G. Review: Overcoming the paradox of strength and ductility in ultrafine-grained materials at low temperatures. J. Mater. Sci. 2016;51:7–18. doi: 10.1007/s10853-015-9143-5. DOI

Zehetbauer M.J., Stüve H.P., Vorhauer A., Schafler E., Kohout J. The role of hydrostatic pressure in severe plastic deformation. Adv. Eng. Mater. 2003;5:330–337. doi: 10.1002/adem.200310090. DOI

Morozova A., Borodin E., Bratov V., Zherebtsov S., Belyakov A., Kaibyshev R. Grain refinement kinetics in a low alloyed Cu–Cr–Zr alloy subjected to large strain deformation. Materials. 2017;10:1394. doi: 10.3390/ma10121394. PubMed DOI PMC

Kunčická L., Kocich R., Král P., Pohludka M., Marek M. Effect of strain path on severely deformed aluminium. Mater. Lett. 2016;180:280–283. doi: 10.1016/j.matlet.2016.05.163. DOI

Král P., Dvořák J., Kvapilová M., Blum W., Sklenička V. The influence of long-term annealing at room temperature on creep behaviour of ECAP-processed copper. Mater. Lett. 2017;188:235–238. doi: 10.1016/j.matlet.2016.11.002. DOI

Král P., Blum W., Dvořák J., Eisenlohr P., Petrenec M., Sklenička V. Dynamic restoration of severely predeformed, ultrafine-grained pure Cu at 373 K observed in situ. Mater. Charact. 2017;134:329–334. doi: 10.1016/j.matchar.2017.11.006. DOI

Blum W., Zeng X.H. A simple dislocation model of deformation resistance of ultrafine-grained materials explaining Hall–Petch strengthening and enhanced strain rate sensitivity. Acta Mater. 2009;57:1966–1974. doi: 10.1016/j.actamat.2008.12.041. DOI

Li Y.J., Zeng X.H., Blum W. Transition from strengthening to softening by grain boundaries in ultrafine-grained Cu. Acta Mater. 2014;52:5009–5018. doi: 10.1016/j.actamat.2004.07.003. DOI

Sklenička V., Dvorak J., Svoboda M. Creep in ultrafine grained aluminium. Mater. Sci. Eng. A. 2004;387–389:696–701. doi: 10.1016/j.msea.2004.01.111. DOI

Abe F., Kern T.-U., Viswanathan R. Creep-Resistant Steels. Woodhead Publishing; Sawston, Cambridge, UK: 2008.

Kaibyshev R.O., Skorobogatykh V.N., Shchenkova I.A. New martensitic steels for fossil power plant: Creep resistance. Phys. Metals Metallogr. 2010;109:186–200. doi: 10.1134/S0031918X10020110. DOI

Abe F. Creep rates and strengthening mechanisms in tungsten-strengthened 9Cr steels. Mater. Sci. Eng. A. 2001;319–321:770–7723. doi: 10.1016/S0921-5093(00)02002-5. DOI

Dudova N., Plotnikova A., Molodov D., Belyakov A., Kaibyshev R. Structural changes of tempered martensitic 9% Cr–2% W–3% Co steel during creep at 650 °C. Mater. Sci. Eng. A. 2012;543:632–639. doi: 10.1016/j.msea.2011.12.020. DOI

Spigarelli S., Cerri E., Bianchi P., Evangelista E. Interpretation of creep behavior of a 9Cr-Mo-Nb-V-N (T91) steel using threshold stress concept. Mater. Sci. Technol. 1999;15:1433–1440. doi: 10.1179/026708399101505428. DOI

Kostka A., Tak T.-G., Eggeler G. On the effect of equal-channel angular pressing on creep of tempered martensite ferritic steels. Mater. Sci. Eng. A. 2008;481–482:723–726. doi: 10.1016/j.msea.2007.02.154. DOI

Hattestrand M., Andren H.-O. Influence of strain on precipitation reactions during creep of an advanced 9% chromium steel. Acta Mater. 2001;49:2123–2128. doi: 10.1016/S1359-6454(01)00135-5. DOI

Hald J. Microstructure and long-term creep properties of 9–12% Cr steels. Int. J. Press. Vessels Pip. 2008;85:30–37. doi: 10.1016/j.ijpvp.2007.06.010. DOI

Li Q. Precipitation of Fe2W Laves phase and modelling of its direct influence on the strength of a 12Cr-2W steel. Metall. Mater. Trans. 2006;37:89–97. doi: 10.1007/s11661-006-0155-2. DOI

Prat O., Garcia J., Rojas D., Sauthoff G., Inden G. The role of Laves phase on microstructure evolution and creep strength of novel 9%Cr heat resistant steels. Intermetallics. 2013;32:362–372. doi: 10.1016/j.intermet.2012.08.016. DOI

Kassner M.E., Pérez-Prado M.-T. Fundamentals of Creep in Metals and Alloys. Elsevier; Amsterdam, The Netherlands: 2004. pp. 121–139.

Král P., Dvořák J., Jäger A., Kvapilová M., Horita Z., Sklenička V. Creep properties of aluminium processed by ECAP. Kovove Mater. 2016;54:441–451. doi: 10.4149/km_2016_6_441. DOI

Takizawa Y., Kajita T., Kral P., Masuda T., Watanabe K., Yumoto M., Otagiri Y., Sklenicka V., Horita Z. Super plasticity of Inconel 718 after processing by high-pressure sliding (HPS) Mater. Sci. Eng. A. 2017;682:603–612. doi: 10.1016/j.msea.2016.11.081. DOI

Kral P., Dvorak J., Sklenicka V., Masuda T., Horita Z., Kucharova K., Kvapilova M., Svobodova M. Microstructure and creep behaviour of P92 steel after HPT. Mater. Sci. Eng. A. 2018;723:287–295. doi: 10.1016/j.msea.2018.03.059. PubMed DOI PMC

Sklenicka V., Kuchařová K., Král P., Kvapilová M., Svobodová M., Čmakal J. The effect of hot bending and thermal ageing on creep and microstructure evolution in thick-walled P92 steel pipe. Mater. Sci. Eng. A. 2015;644:297–309. doi: 10.1016/j.msea.2015.07.072. DOI

Čadek J., Šustek V., Pahutová M. An analysis of a set of creep data for a 9Cr-IMo-0.2V (P91 type) steel. Mater. Sci. Eng. A. 1997;225:22–28. doi: 10.1016/S0921-5093(96)10569-4. DOI

Sawada K., Takeda M., Maruyama K., Ishii R., Yamada M., Nagae Y., Komine R. Effect of W on recovery of lath structure during creep of high chromium martensitic steels. Mater. Sci. Eng. A. 1999;267:19–25. doi: 10.1016/S0921-5093(99)00066-0. DOI

Maruyama K., Sawada K., Koike J. Strengthening mechanisms of creep resistant tempered martensitic steel. ISIJ Int. 2001;41:641–653. doi: 10.2355/isijinternational.41.641. DOI

Sonderegger B., Mitsche S., Cerjak H. Microstructural analysis on a creep resistant martensitic 9–12% Cr steel using the EBSD method. Mater. Sci. Eng. A. 2008;481–482:466–470. doi: 10.1016/j.msea.2006.12.220. DOI

Abe F. Effect of fine precipitation and subsequent coarsening of fe2w laves phase on the creep deformation behavior of tempered martensitic 9cr-w steels. Metall. Mater. Trans. A. 2005;36:321–332. doi: 10.1007/s11661-005-0305-y. DOI

Aghajani A., Somsen C., Eggeler G. On the effect of long-term creep on the microstructure of a 12% chromium tempered martensite ferritic steel. Acta Mater. 2009;57:5093–5106. doi: 10.1016/j.actamat.2009.07.010. DOI

Cui J., Kim I.-S., Kang C.-Y., Miyahara K. Creep stress effect on the precipitation behavior of Laves-phase in Fe–10% Cr–6%W alloys. ISIJ Int. 2001;41:368–371. doi: 10.2355/isijinternational.41.368. DOI

Panait C.G., Bendick W., Fuchsmann A., Gourgues-Lorenzon A.-F., Besson J. Study of the microstructure of the Grade 91 steel after more than 100,000 h of creep exposure at 600 °C. Int. J. Press. Vessels Pip. 2010;87:326–335. doi: 10.1016/j.ijpvp.2010.03.017. DOI

Eggeler G. The effect of long-term creep on particle coarsening in tempered martensite ferritic steels. Acta Metall. 1989;37:3225–3234. doi: 10.1016/0001-6160(89)90194-6. DOI

Zhao Y.Z., Liao X.Z., Jin Z., Valiev R.Z., Zhu Y.T. Microstructures and mechanical properties of ultrafine grained 7075 Al alloy processed by ECAP and their evolutions during annealing. Acta Mater. 2004;52:4589–4599. doi: 10.1016/j.actamat.2004.06.017. DOI

Hu T., Ma K., Topping T.D., Schoenung J.M., Lavernia E.J. Precipitation phenomena in an ultrafine-grained Al alloy. Acta Mater. 2013;61:2163–2178. doi: 10.1016/j.actamat.2012.12.037. DOI

Sawada K., Kubo K., Abe F. Creep behavior and stability of MX precipitates at high temperature in 9Cr-0.5Mo-1.8W-VNb steel. Mater. Sci. Eng. A. 2001;319:784–787. doi: 10.1016/S0921-5093(01)00973-X. DOI

Kloc L., Sklenicka V. Transition from power-law to viscous creep behaviour of P-91 type heat-resistant steel. Mater. Sci. Eng. A. 1997;234:962–965. doi: 10.1016/S0921-5093(97)00364-X. DOI

Lee J.S., Armaki H.G., Maruyama K., Muraki T., Asahi H. Causes of breakdown of creep strength in 9Cr-1.8W-0.5Mo-VNb steel. Mater. Sci. Eng. A. 2006;428:270–275. doi: 10.1016/j.msea.2006.05.010. DOI

Kawasaki M., Langdon T.G. Review: Achieving superplastic properties in ultrafine-grained materials at high temperatures. J. Mater. Sci. 2016;51:19–32. doi: 10.1007/s10853-015-9176-9. DOI

Zherebtsov S.V., Kudryavtsev E.A., Salishchev G.A., Straumal B.B., Semiatin S.L. Microstructure evolution and mechanical behavior of ultrafine Ti-6Al-4V during low-temperature superplastic deformation. Acta Mater. 2016;121:152–163. doi: 10.1016/j.actamat.2016.09.003. DOI

Abe F. Bainitic and martensitic creep/resistant steels. Curr. Opin. Solid State Mater. Sci. 2004;8:305–311. doi: 10.1016/j.cossms.2004.12.001. DOI

Agamennone R., Blum W., Gupta C., Chakravartty J.K. Evolution of microstructure and deformation resistance in creep of tempered martensitic 9–12% Cr–2% W–5% Co steels. Acta Mater. 2006;54:3003–3014. doi: 10.1016/j.actamat.2006.02.038. DOI

Langdon T.G. A unified approach to grain boundary sliding in creep and superplasticity. Acta Metall. Mater. 1994;42:2437–2443. doi: 10.1016/0956-7151(94)90322-0. DOI

Frost H.J., Ashby M.F. Deformation-Mechanism Maps. Pergamon Press; Oxford, UK: 1982. pp. 62–63.

Blum W., Zeng X.H. Corrigendum to: “A simple dislocation model of deformation resistance of ultrafine-grained materials explaining Hall-Petch strengthening and enhanced strain rate sensitivity”. Acta Mater. 2011;59:6205–6206. doi: 10.1016/j.actamat.2011.05.032. DOI

Owen D.M., Langdon T.G. Low stress creep behavior: An examination of Nabarro-Herring and Harper-Dorn creep. Mater. Sci. Eng. A. 1996;216:20–29. doi: 10.1016/0921-5093(96)10382-8. DOI

Abe F., Araki H., Noda T. The effect of tungsten on dislocation recovery and precipitation behaviour of low-activation martensitic 9Cr steels. Metall. Trans. A. 1991;22:2225–2235. doi: 10.1007/BF02664988. DOI

Burton B. Diffusional Creep of Polycrystalline Materials. Trans Tech S. A.; Aedermannsdorf, Switzerland: 1977. p. 119.

Creep Resistance of S304H Austenitic Steel Processed by High-Pressure Sliding

The Effect of Predeformation on Creep Strength of 9% Cr Steel

The Effect of Electrolytic Hydrogenation on Mechanical Properties of T92 Steel Weldments under Different PWHT Conditions

The Effect of Ultrafine-Grained Microstructure on Creep Behaviour of 9% Cr Steel