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| EFFECT OF TWIN LAMELLAR THICKNESS ON THE FATIGUE PROPERTIES OF NANO--TWINNED Cu |
| TANG Lian; LU Lei |
| Shenyang National Laboratory for Materials Science; Institute of Metal Research; Chinese Academy of Sciences; Shenyang 110016 |
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Cite this article:
TANG Lian LU Lei. EFFECT OF TWIN LAMELLAR THICKNESS ON THE FATIGUE PROPERTIES OF NANO--TWINNED Cu. Acta Metall Sin, 2009, 45(7): 808-814.
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Abstract The fatigue property of
metals is one of the most important concerns in industrial design.
It is affected by various factors, such as the microstructure,
mechanics and the environment. For the polycrystalline metallic
materials, grain boundaries (GBs) usually play an important role and
affect the fatigue behaviors significantly. GBs could strengthen
materials by blocking the motion of dislocations; meanwhile, the
stress concentration which is caused by the dislocations pile--up in
the vicinity of GBs would result in the initial fatigue crack
easily. As a special interface of low--energy, twin boundaries (TBs)
can strengthen materials by blocking the motion of dislocations in a
manner similar to that of GBs. Our studies have indicated that a
high density of nano--scale twin lamellae can provide the high
strength without significantly compromising ductility, which is
fundamentally different from that of GB strengthening. So far, most
studies of the TB--related fatigue and cracking behaviors are
concentrated on the twins with a thickness of few or tens
micrometers. The study of the TB--related fatigue behavior in
nanometer scale is rare. In this work, high--purity Cu specimens
with high density of nano--scale coherent TBs were synthesized by
means of the pulsed electro--deposition (PED). The twin lamellar
thickness dependence of fatigue life and fatigue endurance limit of
the nano--twinned Cu (nt--Cu) were studied by conducting
tension--tension fatigue tests under constant stress amplitude
control at room temperature. It is found that both the fatigue life
and fatigue endurance limit increase with the decrease of the twin
lamellar thickness. Postmortem SEM observations suggest a transition
in crack initiation site from shear bands (SBs) to TBs, when the
twin lamellar thickness is reduced from 85 to 32 nm. For the nt--Cu
samples with thick twin lamellae, the lattices accommodate the
plastic strain, which results in the SB cracking. For the nt--Cu
samples with thin twin lamellae, the abundant TBs accommodate the
plastic strain. The stress concentration along TBs which is caused
by the interactions of dislocation--TBs facilitates the fatigue cracking along TBs.
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Received: 31 March 2009
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| Fund: Supported by National Natural Science Foundation of China (Nos.50571096, 50621091, 50725103 and 50890171) and National Basic Research Program of China (No.2005CB623604) |
| [1] Thompson A W, Backofen W A. Acta Metall, 1971; 19: 597
[2] Lukas P, Kunz L. Mater Sci Eng, 1987; 85: 67
[3] Agnew S R, Vinogradov A Y, Hashimoto S, Weertman J R. J Electron Mater, 1999; 28: 1038
[4] Hoppel H W, Brunnbauer M, Mughrabi H, Valiev R Z, Zhilyaev A P. Proc Int Conf on Proc of Materialsweek 2000, Frankfurt, 2000, available from: http://www.materialsweek.org/proceedings
[5] Vinogradov A, Hashimoto S. Mater Trans, 2001; 42: 74
[6] Kunz L, Lukas P, Svoboda M. Mater Sci Eng, 2006; A424: 97
[7] Xu C, Wang Q, Zheng M, Li J, Huang M, Jia Q, Zhu J, Kunz L, Buksa M. Mater Sci Eng, 2008; A475: 249
[8] Wu S D,Wang Z G, Jiang C B, Li G Y, Alexandrov I V, Valiev R Z. Mater Sci Eng, 2004; A387–389: 560
[9] Meyers M A, Chawla K K. Mechanical Behavior of Materials. Upper Saddle River, NJ 07458: Prentice Hall, Inc., 1999: 257
[10] Murr L E, Moin E, Greulich F, Staudhammer K P. Scr Metall, 1978; 12: 1031
[11] Shen Y F, Lu L, Lu Q H, Jin Z H, Lu K. Scr Mater, 2005; 52: 989
[12] Thompson N,Wadsworth N J, Louat N. Philos Mag, 1956; 1: 113
[13] Thompson N. In: Aversbach B L ed., Proc Int Conf on Atomic Mechanisms of Fracture, London: Chapman and Hall, 1959: 354
[14] Boettner R C, McEvily A J, Liu Y C. Philos Mag, 1964; 10: 95
[15] Wang Z R, Margolin H. Metall Trans, 1985; 16A: 873
[16] Hook R E, Hirth J P. Acta Metall, 1967; 15: 535
[17] Neumann P, Tonnessen A. In: Kettunen P O ed., Proc Int Conf on Strength of Metals and Alloys, Oxford: Pergamon Press, 1988: 743
[18] Qu S, Zhang P, Wu S D, Zang Q S, Zhang Z F. Scr Mater, 2008; 59: 1131
[19] Suresh S. Fatigue of Materials. Cambrige: Cambridge University Press, 1991: 134
[20] Chen X H, Lu L. Scr Mater, 2007; 57: 133
[21] Asaro R J, Kulkarni Y. Scr Mater, 2008; 58: 389
[22] Jin ZH,Gumbsch P,Ma E, Albe K, LuK, Hahn H, Gleiter H. Scr Mater, 2006; 54: 1163
[23] Hanlon T, Tabachnikova E D, Suresh S. Int J Fatigue, 2005; 27: 1147
[24] Jin Z H, Gumbsch P, Albe K, Ma E, Lu K, Gleiter H, Hahn H. Acta Mater, 2008; 56: 1126
[25] Lee C S, Duggan B J. Acta Metall Mater, 1994; 42: 857
[26] Mughrabi H, Hoppel HW. Proc Symposium Structure and Mechanical Properties of Nanophase Materials–Theory and Computer Simulation vs Experiment, Material Research Society Symposium Proceeding, vol. 634, Boston, 2000: B2.1.1
[27] Wu S D, Wang Z G, Jiang C B, Li G Y, Alexandrov I V, Valiev R Z. Scr Mater, 2003; 48: 1605
[28] Goto M, Han S Z, Yakushiji T, Lim C Y, Kim S S. Scr Mater, 2006; 54: 2101
[29] Zhang P, Duan Q Q, Li S X, Zhang Z F. Philos Mag, 2008; 88: 2487 |
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