The effect of grain boundaries (GBs) on deformation mechanisms becomes increasingly important as the volume of deformation reaches the submicrometer and nanoscale. The current work investigates the impact of grain boundaries on the incipient plasticity of small-scale deformations of fcc metals. For this purpose, the behavior of single and bi-crystal Au thin films during nanoindentation are studied, using large-scale atomistic simulations. Various symmetric ⟨110⟩ tilt GBs with a wide range of misorientation angles are included to analyze the effect of GB geometry on the nanoscale plasticity mechanisms. Potentially, GBs can act as a source, sink, or obstacle for lattice dislocation, depending on their geometry, energy level, and distance from the deformation zone. The role of the heterogeneous nucleation and emission of dislocations from GBs on the plasticity and hardness of bicrystals is analyzed. According to our results, the intrinsic free volume involved in the GB region is associated with dislocation nucleation at the GB. The volume of the plastic zone generated beneath the tip and the way it grows is strongly dependent on the GB structure. Dislocation nucleation occurs predominantly in the early stages of indentation at GBs with a dissociated interface structural unit, before the interaction of lattice dislocation and GB. Coherent twin boundaries display the lowest effect on the hardness. Based on our results, there is a strong correlation between the interfacial boundary energy and its effect on the bicrystal hardness. GBs with lower interfacial energy offer a higher barrier against slip transmission and nucleation at the GB.
REFERENCES
1.
E. O.
Hall
, “The deformation and ageing of mild steel. 3. Discussion of results
,” Proc. Phys. Soc. Sec. B
64
(381
), 747
–753
(1951
). 2.
N. J.
Petch
, “The cleavage strength of polycrystals
,” J. Iron Steel I
174
(1
), 25
–28
(1953
).3.
T. T.
Zhu
, A. J.
Bushby
, and D. J.
Dunstan
, “Materials mechanical size effects: A review
,” Mater. Technol.
23
(4
), 193
–209
(2008
). 4.
V.
Yamakov
, D.
Wolf
, S. R.
Phillpot
, and H.
Gleiter
, “Deformation twinning in nanocrystalline Al by molecular dynamics simulation
,” Acta Mater.
50
(20
), 5005
–5020
(2002
). 5.
V.
Yamakov
, D.
Wolf
, S. R.
Phillpot
, and H.
Gleiter
, “Dislocation-dislocation and dislocation-twin reactions in nanocrystalline Al by molecular dynamics simulation
,” Acta Mater.
51
(14
), 4135
–4147
(2003
). 6.
V.
Yamakov
, D.
Wolf
, S. R.
Phillpot
, A. K.
Mukherjee
, and H.
Gleiter
, “Deformation mechanism crossover and mechanical behaviour in nanocrystalline materials
,” Philos. Mag. Lett.
83
(6
), 385
–393
(2003
). 7.
D.
Wolf
, V.
Yamakov
, S. R.
Phillpot
, A.
Mukherjee
, and H.
Gleiter
, “Deformation of nanocrystalline materials by molecular-dynamics simulation: Relationship to experiments?
,” Acta Mater.
53
(1
), 1
–40
(2005
). 8.
K. E.
Aifantis
, W. A.
Soer
, J. T. M.
De Hosson
, and J. R.
Willis
, “Interfaces within strain gradient plasticity: Theory and experiments
,” Acta Mater.
54
(19
), 5077
–5085
(2006
). 9.
D. E.
Spearot
, M. A.
Tschopp
, K. I.
Jacob
, and D. L.
McDowell
, “Tensile strength of ⟨100⟩ and ⟨110⟩ tilt bicrystal copper interfaces
,” Acta Mater.
55
(2
), 705
–714
(2007
). 10.
M. A.
Tschopp
and D. L.
McDowell
, “Dislocation nucleation in Σ3 asymmetric tilt grain boundaries
,” Int. J. Plast.
24
(2
), 191
–217
(2008
). 11.
E. T.
Lilleodden
, J. A.
Zimmerman
, S. M.
Foiles
, and W. D.
Nix
, “Atomistic simulations of elastic deformation and dislocation nucleation during nanoindentation
,” J. Mech. Phys. Solids
51
(5
), 901
–920
(2003
). 12.
K. J.
Kim
, J. H.
Yoon
, M. H.
Cho
, and H.
Jang
, “Molecular dynamics simulation of dislocation behavior during nanoindentation on a bicrystal with a Σ = 5 (210) grain boundary
,” Mater. Lett.
60
(28
), 3367
–3372
(2006
). 13.
A.
Hasnaoui
, P. M.
Derlet
, and H.
Van Swygenhoven
, “Interaction between dislocations and grain boundaries under an indenter—A molecular dynamics simulation
,” Acta Mater.
52
(8
), 2251
–2258
(2004
). 14.
H.
Jang
and D.
Farkas
, “Interaction of lattice dislocations with a grain boundary during nanoindentation simulation
,” Mater. Lett.
61
(3
), 868
–871
(2007
). 15.
T.
Tsuru
, Y.
Kaji
, D.
Matsunaka
, and Y.
Shibutani
, “Incipient plasticity of twin and stable/unstable grain boundaries during nanoindentation in copper
,” Phys. Rev. B
82
(2
), 024101
(2010
). 16.
M. D.
Sangid
, T.
Ezaz
, H.
Sehitoglu
, and I. M.
Robertson
, “Energy of slip transmission and nucleation at grain boundaries
,” Acta Mater.
59
(1
), 283
–296
(2011
). 17.
L.
Zhang
, C.
Lu
, and K.
Tieu
, “Atomistic simulation of tensile deformation behavior of Σ5 tilt grain boundaries in copper bicrystal
,” Sci. Rep.
4
, 5919
(2014
). 18.
M. S.
Talaei
, N.
Nouri
, and S.
Ziaei-Rad
, “Grain boundary effects on nanoindentation of Fe bicrystal using molecular dynamic
,” Mech. Mater.
102
, 97
–107
(2016
). 19.
G. Z.
Voyiadjis
and M.
Yaghoobi
, “Role of grain boundary on the sources of size effects
,” Comp. Mater. Sci.
117
, 315
–329
(2016
). 20.
B. R.
Kuhr
and K. E.
Aifantis
, “Interpreting the inverse Hall-Petch relationship and capturing segregation hardening by measuring the grain boundary yield stress through MD indentation
,” Mater. Sci. Eng. A
745
, 107
–114
(2019
). 21.
K. E.
Aifantis
, H.
Deng
, H.
Shibata
, S.
Tsurekawa
, P.
Lejček
, and S. A.
Hackney
, “Interpreting slip transmission through mechanically induced interface energies: A Fe–3%Si case study
,” J. Mater. Sci.
54
(2
), 1831
–1843
(2019
). 22.
S.
Plimpton
, “Fast parallel algorithms for short-range molecular-dynamics
,” J. Comput. Phys.
117
(1
), 1
–19
(1995
). 23.
S.
Nosé
, “A unified formulation of the constant temperature molecular-dynamics methods
,” J. Chem. Phys.
81
(1
), 511
–519
(1984
). 24.
S. M.
Foiles
, M. I.
Baskes
, and M. S.
Daw
, “Embedded-atom-method functions for the Fcc metals Cu, Ag, Au, Ni, Pd, Pt, and their alloys
,” Phys. Rev. B
33
(12
), 7983
–7991
(1986
). 25.
G.
Ziegenhain
, H. M.
Urbassek
, and A.
Hartmaier
, “Influence of crystal anisotropy on elastic deformation and onset of plasticity in nanoindentation: A simulational study
,” J. Appl. Phys.
107
(6
), 061807
(2010
). 26.
T.
Cheng
, D.
Fang
, and Y.
Yang
, “The temperature dependence of grain boundary free energy of solids
,” J. Appl. Phys.
123
(8
), 085902
(2018
). 27.
J. D.
Rittner
, D. N.
Seidman
, and K. L.
Merkle
, “Grain-boundary dissociation by the emission of stacking faults
,” Phys. Rev. B
53
(8
), R4241
–R4244
(1996
). 28.
29.
J. D.
Rittner
and D. N.
Seidman
, “⟨110⟩ symmetric tilt grain-boundary structures in fcc metals with low stacking-fault energies
,” Phys. Rev. B
54
(10
), 6999
–7015
(1996
). 30.
C. L.
Kelchner
, S. J.
Plimpton
, and J. C.
Hamilton
, “Dislocation nucleation and defect structure during surface indentation
,” Phys. Rev. B
58
(17
), 11085
–11088
(1998
). 31.
L.
Zhang
, C.
Lu
, K.
Tieu
, L.
Pei
, X.
Zhao
, and K.
Cheng
, “Molecular dynamics study on the grain boundary dislocation source in nanocrystalline copper under tensile loading,” Mater. Res. Express
2
, 035009
(2015
).32.
M. J.
Mills
, M. S.
Daw
, G. J.
Thomas
, and F.
Cosandey
, “High-resolution transmission electron microscopy of grain boundaries in aluminum and correlation with atomistic calculations
,” Ultramicroscopy
40
(3
), 247
–257
(1992
). 33.
O. H.
Duparc
, S.
Poulat
, A.
Larere
, J.
Thibault
, and L.
Priester
, “High-resolution transmission electron microscopy observations and atomic simulations of the structures of exact and near Σ = 11, {332} tilt grain boundaries in nickel
,” Philos. Mag. A
80
(4
), 853
–870
(2000
). 34.
S.
Poulat
, J.
Thibault
, and L.
Priester
, “HRTEM studies of the structures and the defects of exact and near ∑ = 11 {332} tilt grain boundaries in Ni
,” Interface Sci.
8
(1
), 5
–15
(2000
). 35.
E. A.
Marquis
and D. L.
Medlin
, “Structural duality of 1/3⟨111⟩ twin-boundary disconnections
,” Philos. Mag. Lett.
85
(8
), 387
–394
(2005
). 36.
A.
Stukowski
and K.
Albe
, “Extracting dislocations and non-dislocation crystal defects from atomistic simulation data
,” Model Simul. Mater. Sc.
18
(8
), 085001
(2010
). 37.
A.
Stukowski
, “Visualization and analysis of atomistic simulation data with OVITO—The Open Visualization Tool
,” Model Simul. Mater. Sci.
18
(1
), 015012
(2010
). 38.
T.
Tsuru
, Y.
Shibutani
, and Y.
Kaji
, “Fundamental interaction process between pure edge dislocation and energetically stable grain boundary
,” Phys. Rev. B
79
(1
), 012104
(2009
). 39.
L.
Zhang
, C.
Lu
, K.
Tieu
, X.
Zhao
, and L.
Pei
, “The shear response of copper bicrystals with Σ11 symmetric and asymmetric tilt grain boundaries by molecular dynamics simulation
,” Nanoscale
7
(16
), 7224
–7233
(2015
). 40.
L.
Smith
and D.
Farkas
, “Deformation response of grain boundary networks at high temperature
,” J. Mater. Sci.
53
(8
), 5696
–5705
(2018
). 41.
M. A.
Tschopp
and D. L.
McDowell
, “Grain boundary dislocation sources in nanocrystalline copper
,” Scripta. Mater.
58
(4
), 299
–302
(2008
). 42.
X. Y.
Li
, Y. J.
Wei
, L.
Lu
, K.
Lu
, and H. J.
Gao
, “Dislocation nucleation governed softening and maximum strength in nano-twinned metals
,” Nature
464
(7290
), 877
–880
(2010
). 43.
Z. S.
You
, X. Y.
Li
, L. J.
Gui
, Q. H.
Lu
, T.
Zhu
, H. J.
Gao
, and L.
Lu
, “Plastic anisotropy and associated deformation mechanisms in nanotwinned metals
,” Acta Mater.
61
(1
), 217
–227
(2013
). 44.
T.
Fu
, X. H.
Peng
, X.
Chen
, S. Y.
Weng
, N.
Hu
, Q. B.
Li
, and Z. C.
Wang
, “Molecular dynamics simulation of nanoindentation on Cu/Ni nanotwinned multilayer films using a spherical indenter
,” Sci. Rep.
6
, 35665
(2016
). 45.
A. G.
Frøseth
, P. M.
Derlet
, and H.
Van Swygenhoven
, “Vicinal twin boundaries providing dislocation sources in nanocrystalline Al
,” Scr. Mater.
54
(3
), 477
–481
(2006
). 46.
S. M.
Foiles
and D. L.
Medlin
, “Structure and climb of twin dislocations in aluminum
,” Mater. Sci. Eng.
319–321
, 102
–106
(2001
). 47.
D. E.
Spearot
, “Evolution of the E structural unit during uniaxial and constrained tensile deformation
,” Mech. Res. Commun.
35
(1
), 81
–88
(2008
). 48.
F.
Sansoz
and J. F.
Molinari
, “Mechanical behavior of Σ tilt grain boundaries in nanoscale Cu and Al: A quasicontinuum study
,” Acta Mater.
53
(7
), 1931
–1944
(2005
). 49.
X.
Hu
, Y.
Ni
, and Z.
Zhang
, “Atomistic study of interactions between intrinsic kink defects and dislocations in twin boundaries of nanotwinned copper during nanoindentation
,” Nanomaterials
10
(2
), 221
(2020
). © 2020 Author(s).
2020
Author(s)
You do not currently have access to this content.
