Abstract
In several experimental microstructure-based studies on steady-state deformation in high-temperature creep and, in particular, in cyclic deformation it has been observed that non-negligible microstructural changes persist after the macroscopic stress–strain response has become stationary. These microstructural changes are related primarily to a slight increase of the dislocation density, mainly in the form of geometrically necessary dislocations (GND) in the cell walls/subgrain boundaries. The latter are initially associated with only minor misorientations but then transform gradually into much sharper subgrain boundaries with higher misorientations. It is interesting to note that these continuing microstructural changes do not affect the flow stress significantly and therefore do not cause appreciable deviations from steady state. The following natural explanation is proposed: 1) The added GND do strengthen the material, but not as effectively as statistically stored dislocations would do. 2) As a consequence of the transition of the initial dislocation arrangement to one of lower internal stresses and lower energy, the “arrangement factor” in the Taylor flow-stress law is reduced a little. Thus, in the Taylor flow-stress law, the effects named above can be, to some extent, self-compensating, rendering the flow stress rather insensitive to subtle microstructural changes. The dependence of the flow stress on microstructural quantities such as the dislocation density and the cell/subgrain size can be described in good approximation by well-known semiempirical relationships and almost irrespective of the details and type of deformation not only for steady-state, but also for non-steady-state deformation. This suggests that the gross strength-governing features of the deformation-induced dislocation microstructure are rather similar in all cases discussed.
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It is a pleasure to thank my colleague Wolfgang Blum sincerely for frequent inspiring, sometimes heated discussions about many different aspects of crystal plasticity.
References
[1] W. Blum: Z. Metallkd. 68 (1977) 484.Suche in Google Scholar
[2] W. Blum, in: H. Mughrabi (Ed.), Plastic Deformation and Fracture of Materials, Vol. 6 of Materials Science and Technology, R.W. Cahn, P. Haasen, E.J. Kramer (Eds.), VCH Verlagsgesellschaft, Weinheim (1993) 359.Suche in Google Scholar
[3] W. Blum, P. Eisenlohr, F. Breutinger: Metall. Mater. Trans. A 33 (2002) 291.10.1007/s11661-002-0090-9Suche in Google Scholar
[4] Z.S. Basinski, A.S. Korbel, S.J. Basinski: Acta metall. 28 (1980)191.10.1016/0001-6160(80)90068-1Suche in Google Scholar
[5] Z.S. Basinski, S.J. Basinski: Progr. Mater. Sci. 36 (1992) 89.10.1016/0079-6425(92)90006-SSuche in Google Scholar
[6] H. Shirai, J.R. Weertman: Scripta metall. 17 (1983) 1253.10.1016/0036-9748(83)90294-6Suche in Google Scholar
[7] L.L. Lisiecki, J.R. Weertman: Acta metall. mater. 38 (1990) 509.10.1016/0956-7151(90)90157-CSuche in Google Scholar
[8] M. Bayerlein: Doctoral Thesis, Universität Erlangen–Nürnberg (1991).Suche in Google Scholar
[9] J. Bretschneider, C. Holste, B. Tippelt: Acta mater. 45 (1997) 3775.10.1016/S1359-6454(97)00030-XSuche in Google Scholar
[10] C. Holste, J. Bretschneider, B. Tippelt: Mater. Sci. Eng. A 234 (1997) 743.10.1016/S0921-5093(97)00385-7Suche in Google Scholar
[11] R.W. Evans, B. Wilshire: Creep of Metals and Alloys, Institute of Metals, London (1985).Suche in Google Scholar
[12] S. Takeuchi, A.S. Argon: J. Mater. Sci. 11 (1976) 1542.10.1007/BF00540888Suche in Google Scholar
[13] J.D. Morrow, in: Internal Friction, Damping and Cyclic Plasticity, ASTM STP 378, American Society for Testing and Materíals, Philadelphia (1965) 45.Suche in Google Scholar
[14] J.C. Grosskreutz: phys. stat. sol. (b) 47 (1971) 11.10.1002/pssb.2220470102Suche in Google Scholar
[15] A. Rosen, L. Bendersky, Y. Komem, in: N. Hansen et al. (Eds.): Deformation of Polycrystals: Mechanics and Microstructures, Proc. of 2nd Risoe International Symposium on Metallurgy and Materials Science, Risø National Laboratory, Roskilde (1981) 351.Suche in Google Scholar
[16] M.A. Morris, J.L. Martin: Acta metall. 32 (1984) 1609.10.1016/0001-6160(84)90220-7Suche in Google Scholar
[17] F. Petry, F. Pschenitzka: Mater. Sci. Eng. 68 (1984) L7.10.1016/0025-5416(84)90258-1Suche in Google Scholar
[18] S.H. Su, J.B. Cohen, J. Weertman: Metall. Trans. A 14 (1983) 117.Suche in Google Scholar
[19] A. Orlová, J. Cadek: Mater. Sci. Eng. 77 (1986) 1.10.1016/0025-5416(86)90349-6Suche in Google Scholar
[20] H. Mughrabi, T. Ungár, in: F.R.N. Nabarro, M.S. Duesbury (Eds.), Dislocations in Solids, vol. 11, North-Holland Elsevier (2002) 374.Suche in Google Scholar
[21] J. Polák: Czech J. Phys. 3 (1969) 315.10.1007/BF01712868Suche in Google Scholar
[22] M. Wilkens, K. Herz, H. Mughrabi: Z. Metallkd. 71 (1980) 376.Suche in Google Scholar
[23] H. Mughrabi, K. Herz, X. Stark: Int. J. Fract. 17 (1981) 193.10.1007/BF00053520Suche in Google Scholar
[24] H. Mughrabi, R. Kütterer, K. Lubitz, H. Kronmüller: phys. stat. sol. (a) 38 (1976) 261.10.1002/pssa.2210380129Suche in Google Scholar
[25] W. Wolf: Doctoral Thesis, Universität Stuttgart (1976).Suche in Google Scholar
[26] M. Hollmann, J. Bretschneider, C. Holste: Cryst. Res. Technol. 35 (2000) 479.10.1002/1521-4079(200004)35:4<479::AID-CRAT479>3.0.CO;2-ESuche in Google Scholar
[27] A. Seeger: Phil. Mag. 45 (1954) 771. \10.1080/14786440708520489Suche in Google Scholar
[28] F.R.N. Nabarro, Z.S. Basinski, D.B. Holt: Adv. Phys. 13 (1964) 193.10.1080/00018736400101031Suche in Google Scholar
[29] A.H. Cottrell: Dislocations and Plastic Flow in Crystals, Oxford University Press (1953) 208.Suche in Google Scholar
[30] G. König, W. Blum: Acta metall. 28 (1980) 519.10.1016/0001-6160(80)90142-XSuche in Google Scholar
[31] H. Mughrabi: Mater. Sci. Eng. A 387 (2004) 209.10.1016/j.msea.2004.01.086Suche in Google Scholar
[32] M.F. Ashby: Phil. Mag. 21 (1970) 399.10.1080/14786437008238426Suche in Google Scholar
[33] J.W. Christian, in: Proc. of 2nd Int. Conf. on the Strength of Metals and Alloys (ICSMA 2),Vol. 2, American Society for Metals, Ohio (1970) 31.Suche in Google Scholar
[34] L.P. Kubin: Rev. on the Deformation Behaviour of Materials, Vol. IV, No. 3 (1982) 181.Suche in Google Scholar
[35] B. Šesták, A. Seeger: Z. Metallkd. 69 (1978) 195, 355, 425.Suche in Google Scholar
[36] A. Seeger, J. Diehl, S. Mader, H. Rebstock: Phil. Mag. 2 (1957) 323.10.1080/14786435708243823Suche in Google Scholar
[37] N. Hansen, X. Huang: Acta mater. 46 (1998) 1827.10.1016/S1359-6454(97)00365-0Suche in Google Scholar
[38] E. Schafler, K. Simon, S. Bernstorff, P. Hanák, G. Tichy, T. Ungár, M. J. Zehetbauer: Acta mater. 53 (2005) 315.10.1016/j.actamat.2004.09.025Suche in Google Scholar
[39] J.E. Pratt, Acta metall. 15 (1967) 319.10.1016/0001-6160(67)90208-8Suche in Google Scholar
[40] S.V. Raj, G.M. Pharr: Mater. Sci. Eng. 81 (1986) 217.10.1016/0025-5416(86)90265-XSuche in Google Scholar
[41] C.E. Feltner, C. Laird: Acta metall. 15 (1967) 1633.10.1016/0001-6160(67)90138-1Suche in Google Scholar
[42] R.C. Daniel, G.T. Horne: Metall. Transact. 2 (1971) 1161.10.1007/BF02664248Suche in Google Scholar
[43] M.R. Staker, D.L. Holt: Acta metal. 20 (1972) 569.10.1016/0001-6160(72)90012-0Suche in Google Scholar
[44] D.J. Abson, J.J. Jonas: Metal Sci. J. 4 (1970) 24.10.1179/msc.1970.4.1.24Suche in Google Scholar
[45] F.N. Mandigo: Ph. D. Thesis, Cornell University (1972).Suche in Google Scholar
[46] D. Kuhlmann-Wilsdorf, in: Work Hardening, J.P. Hirth and J. Weertman (Eds.), Gordon and Breach, New York (1968) 97.Suche in Google Scholar
© 2005 Carl Hanser Verlag, München
Artikel in diesem Heft
- Frontmatter
- Editorial
- Editorial
- Articles Basic
- Identifying creep mechanisms in plastic flow
- A unified microstructural metal plasticity model applied in testing, processing, and forming of aluminium alloys
- Implications of non-negligible microstructural variations during steady-state deformation
- Tertiary creep of metals and alloys
- Interactions between particles and low-angle dislocation boundaries during high-temperature deformation
- Strain-rate sensitivity of ultrafine-grained materials
- Transient plastic flow at nominally fixed structure due to load redistribution
- Vacancy concentrations determined from the diffuse background scattering of X-rays in plastically deformed copper
- Effect of heating rate in α + γ dual-phase field on lamellar microstructure and creep resistance of a TiAl alloy
- About stress reduction experiments during constant strain-rate deformation tests
- Finite-element modelling of anisotropic single-crystal superalloy creep deformation based on dislocation densities of individual slip systems
- Variational approach to subgrain formation
- Articles Applied
- Pseudoelastic cycling of ultra-fine-grained NiTi shape-memory wires
- Creep properties at 125 °C of an AM50 Mg alloy modified by Si additions
- Dependence of mechanical strength on grain structure in the γ′ and oxide dispersions-trengthened nickelbase superalloy PM 3030
- On the improvement of the ductility of molybdenum by spinel (MgAl2O4) particles
- Hot workability and extrusion modelling of magnesium alloys
- Characterization of hot-deformation behaviour of Zircaloy-2: a comparison between kinetic analysis and processing maps
- Requirements for microstructural investigations of steels used in modern power plants
- Influence of Lüders band formation on the cyclic creep behaviour of a low-carbon steel for piping applications
- Creep and creep rupture behaviour of 650 °C ferritic/martensitic super heat resistant steels
- Toughening mechanisms of a Ti-based nanostructured composite containing ductile dendrites
- Notifications/Mitteilungen
- Personal/Personelles
- News/Aktuelles
- Conferences/Konferenzen
Artikel in diesem Heft
- Frontmatter
- Editorial
- Editorial
- Articles Basic
- Identifying creep mechanisms in plastic flow
- A unified microstructural metal plasticity model applied in testing, processing, and forming of aluminium alloys
- Implications of non-negligible microstructural variations during steady-state deformation
- Tertiary creep of metals and alloys
- Interactions between particles and low-angle dislocation boundaries during high-temperature deformation
- Strain-rate sensitivity of ultrafine-grained materials
- Transient plastic flow at nominally fixed structure due to load redistribution
- Vacancy concentrations determined from the diffuse background scattering of X-rays in plastically deformed copper
- Effect of heating rate in α + γ dual-phase field on lamellar microstructure and creep resistance of a TiAl alloy
- About stress reduction experiments during constant strain-rate deformation tests
- Finite-element modelling of anisotropic single-crystal superalloy creep deformation based on dislocation densities of individual slip systems
- Variational approach to subgrain formation
- Articles Applied
- Pseudoelastic cycling of ultra-fine-grained NiTi shape-memory wires
- Creep properties at 125 °C of an AM50 Mg alloy modified by Si additions
- Dependence of mechanical strength on grain structure in the γ′ and oxide dispersions-trengthened nickelbase superalloy PM 3030
- On the improvement of the ductility of molybdenum by spinel (MgAl2O4) particles
- Hot workability and extrusion modelling of magnesium alloys
- Characterization of hot-deformation behaviour of Zircaloy-2: a comparison between kinetic analysis and processing maps
- Requirements for microstructural investigations of steels used in modern power plants
- Influence of Lüders band formation on the cyclic creep behaviour of a low-carbon steel for piping applications
- Creep and creep rupture behaviour of 650 °C ferritic/martensitic super heat resistant steels
- Toughening mechanisms of a Ti-based nanostructured composite containing ductile dendrites
- Notifications/Mitteilungen
- Personal/Personelles
- News/Aktuelles
- Conferences/Konferenzen