Nanotwinned metals are a class of hierarchically structured materials that appear to transcend the limits of conventional material systems by exhibiting an exceptional combination of superior strength, ductility and resistance to fracture, fatigue, and wear. Recently, we reported a type of necklace dislocations in nanotwinned metals which become operative when the twin boundary (TB) spacing falls below a few nanometers. Here, we show that the presence of a cracklike defect as the dominant dislocation source could allow the same mechanism to operate at much larger twin spacings. This finding calls for further theoretical and experimental investigations of a new type of TB related dislocation mechanism which may play particularly important roles in crack-tip deformation in nanotwinned metals.

References

References
1.
Lu
,
L.
,
Shen
,
Y. F.
,
Chen
,
X. H.
,
Qian
,
L. H.
, and
Lu
,
K.
,
2004
, “
Ultrahigh Strength and High Electrical Conductivity in Copper
,”
Science
,
304
(
5669
), pp.
422
426
.10.1126/science.1092905
2.
Lu
,
K.
,
Lu
,
L.
, and
Suresh
,
S.
,
2009
, “
Strengthening Materials by Engineering Coherent Internal Boundaries at the Nanoscale
,”
Science
,
324
(
5925
), pp.
349
352
.10.1126/science.1159610
3.
Lu
,
L.
,
Chen
,
X.
,
Huang
,
X.
, and
Lu
,
K.
,
2009
, “
Revealing the Maximum Strength in Nanotwinned Copper
,”
Science
,
323
(
5914
), pp.
607
610
.10.1126/science.1167641
4.
Li
,
L.
, and
Ghoniem
,
N. M.
,
2009
, “
Twin-Size Effects on the Deformation of Nanotwinned Copper
,”
Phys. Rev. B
,
79
(7), p.
075444
.10.1103/PhysRevB.79.075444
5.
Li
,
X. Y.
,
Wei
,
Y. J.
,
Lu
,
L.
,
Lu
,
K.
, and
Gao
,
H. J.
,
2010
, “
Dislocation Nucleation Governed Softening and Maximum Strength in Nano-Twinned Metals
,”
Nature
,
464
(
7290
), pp.
877
880
.10.1038/nature08929
6.
Stukowski
,
A.
,
Albe
,
K.
, and
Farkas
,
D.
,
2010
, “
Nanotwinned fcc Metals: Strengthening Versus Softening Mechanisms
,”
Phys. Rev. B
,
82
(22), p.
224103
.10.1103/PhysRevB.82.224103
7.
Jang
,
D.
,
Cai
,
C.
, and
Greer
,
J. R.
,
2011
, “
Influence of Homogeneous Interfaces on the Strength of 500 nm Diameter Cu Nanopillars
,”
Nano Lett.
,
11
(
4
), pp.
1743
1746
.10.1021/nl2003076
8.
Bufford
,
D.
,
Wang
,
H.
, and
Zhang
,
X.
,
2011
, “
High Strength, Epitaxial Nanotwinned Ag Films
,”
Acta Mater.
,
59
(
1
), pp.
93
101
.10.1016/j.actamat.2010.09.011
9.
Idrissi
,
H.
,
Wang
,
B. J.
,
Colla
,
M. S.
,
Raskin
,
J. P.
,
Schryvers
,
D.
, and
Pardoen
,
T.
,
2011
, “
Ultrahigh Strain Hardening in Thin Palladium Films With Nanoscale Twins
,”
Adv. Mater.
,
23
(
18
), pp.
2119
2122
.10.1002/adma.201004160
10.
You
,
Z. S.
,
Lu
,
L.
, and
Lu
,
K.
,
2011
, “
Tensile Behavior of Columnar Grained Cu With Preferentially Oriented Nanoscale Twins
,”
Acta Mater.
,
59
(
18
), pp.
6927
6937
.10.1016/j.actamat.2011.07.044
11.
You
,
Z. S.
,
Li
,
X. Y.
,
Gui
,
L. J.
,
Lu
,
Q. H.
,
Zhu
,
T.
,
Gao
,
H. J.
, and
Lu
,
L.
,
2013
, “
Plastic Anisotropy and Associated Deformation Mechanisms in Nanotwinned Metals
,”
Acta Mater.
,
61
(
1
), pp.
217
227
.10.1016/j.actamat.2012.09.052
12.
Zhu
,
T.
, and
Gao
,
H. J.
,
2012
, “
Plastic Deformation Mechanism in Nanotwinned Metals: An Insight From Molecular Dynamics and Mechanistic Modeling
,”
Scr. Mater.
,
66
(
11
), pp.
843
848
.10.1016/j.scriptamat.2012.01.031
13.
Meyers
,
M. A.
,
Mishra
,
A.
, and
Benson
,
D. J.
,
2006
, “
Mechanical Properties of Nanocrystalline Materials
,”
Prog. Mater. Sci.
,
51
(
4
), pp.
427
556
.10.1016/j.pmatsci.2005.08.003
14.
Jang
,
D. C.
,
Li
,
X. Y.
,
Gao
,
H. J.
, and
Greer
,
J. R.
,
2012
, “
Deformation Mechanisms in Nanotwinned Metal Nanopillars
,”
Nat. Nanotechnol.
,
7
(9), pp.
594
601
.10.1038/nnano.2012.116
15.
Wang
,
J. W.
,
Sansoz
,
F.
,
Huang
,
J. Y.
,
Liu
,
Y.
,
Sun
,
S. H.
,
Zhang
,
Z.
, and
Mao
,
S. X.
,
2013
, “
Near-Ideal Theoretical Strength in Gold Nanowires Containing Angstrom Scale Twins
,”
Nat. Commun.
,
4
, p.
1742
.10.1038/ncomms2768
16.
Zhou
,
H. F.
,
Li
,
X. Y.
,
Qu
,
S. X.
,
Yang
,
W.
, and
Gao
,
H. J.
,
2014
, “
A Jogged Dislocation Governed Strengthening Mechanism in Nanotwinned Metals
,”
Nano Lett.
14
(
9
), pp.
5075
5080
.10.1021/nl501755q
17.
Nix
,
W. D.
,
1998
, “
Yielding and Strain Hardening of Thin Metal Films on Substrates
,”
Scr. Mater.
,
39
(
4–5
), pp.
545
554
.10.1016/S1359-6462(98)00195-X
18.
Mishin
,
Y.
,
Mehl
,
M. J.
,
Papaconstantopoulos
,
D. A.
,
Voter
,
A. F.
, and
Kress
,
J. D.
,
2001
, “
Structural Stability and Lattice Defects in Copper: Ab Initio, Tight-Binding, and Embedded-Atom Calculations
,”
Phys. Rev. B
,
63
(
22
), p.
224106
.10.1103/PhysRevB.63.224106
19.
Hoover
,
W. G.
,
1985
, “
Canonical Dynamics: Equilibrium Phase-Space Distributions
,”
Phys. Rev. A
,
31
(
3
), pp.
1695
1697
.10.1103/PhysRevA.31.1695
20.
Faken
,
D.
, and
Jonsson
,
H.
,
1994
, “
Systematic Analysis of Local Atomic Structure Combined With 3D Computer Graphics
,”
Comput. Mater. Sci.
,
2
(
2
), pp.
279
286
.10.1016/0927-0256(94)90109-0
21.
Wang
,
Y. M.
,
Sansoz
,
F.
,
LaGrange
,
T.
,
Ott
,
R. T.
,
Marian
,
J.
,
Barbee
,
T. W.
, Jr.
, and
Hamza
,
A.
V
.
,
2013
, “
Defective Twin Boundaries in Nanotwinned Metals
,”
Nat. Mater.
,
12
(
8
), pp.
697
702
.10.1038/nmat3646
22.
Singh
,
A.
,
Tang
,
L.
,
Dao
,
M.
,
Lu
,
L.
, and
Suresh
,
S.
,
2011
, “
Fracture Toughness and Fatigue Crack Growth Characteristics of Nanotwinned Copper
,”
Acta Mater.
,
59
(
6
), pp.
2437
2446
.10.1016/j.actamat.2010.12.043
23.
Shute
,
C. J.
,
Myers
,
B. D.
,
Xie
,
S.
,
Li
,
S.-Y.
,
Barbee
,
T. W.
,
Hodge
,
A. M.
, and
Weertman
,
J. R.
,
2011
, “
Detwinning, Damage and Crack Initiation During Cyclic Loading of Cu Samples Containing Aligned Nanotwins
,”
Acta Mater.
59
(
11
), pp.
4569
4577
.10.1016/j.actamat.2011.04.002
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