Discrete plasticity in sub-10-nm-sized gold crystals.
Although deformation processes in submicron-sized metallic crystals are well documented, the direct observation of deformation mechanisms in crystals with dimensions below the sub-10-nm range is currently lacking. Here, through in situ high-resolution transmission electron microscopy (HRTEM) observations, we show that (1) in sharp contrast to what happens in bulk materials, in which plasticity is mediated by dislocation emission from Frank-Read sources and multiplication, partial dislocations emitted from free surfaces dominate the deformation of gold (Au) nanocrystals; (2) the crystallographic orientation (Schmid factor) is not the only factor in determining the deformation mechanism of nanometre-sized Au; and (3) the Au nanocrystal exhibits a phase transformation from a face-centered cubic to a body-centered tetragonal structure after failure. These findings provide direct experimental evidence for the vast amount of theoretical modelling on the deformation mechanisms of nanomaterials that have appeared in recent years.
Department of Mechanical Engineering & Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
He
H
Zheng
Ajing
A
Cao
Christopher R
CR
Weinberger
Jian Yu
JY
Huang
Kui
K
Du
Jianbo
J
Wang
Yanyun
Y
Ma
Younan
Y
Xia
Scott X
SX
Mao
Nat Mater. 2003 Oct;2(10):656-60
12958594
J Chem Phys. 2005 Nov 22;123(20):204719
16351305
Nat Mater. 2009 Feb;8(2):95-100
19151703
Phys Rev Lett. 1995 May 15;74(20):3995-3998
10058386
J Am Chem Soc. 2008 Jul 16;130(28):8900-1
18540574
Science. 2004 Aug 13;305(5686):986-9
15310897
ACS Nano. 2009 Oct 27;3(10):3001-8
19743833
Nano Lett. 2007 Jan;7(1):101-7
17212447
Nano Lett. 2005 Dec;5(12):2505-8
16351204
J Microsc. 2006 Jan;221(Pt 1):63-71
16438689
Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6282-6
10841533
Nature. 2006 Jan 19;439(7074):281
16421560
Phys Rev Lett. 2008 Jan 18;100(2):025502
18232884
J Phys Chem B. 2005 May 19;109(19):9703-11
16852169
Phys Rev Lett. 2008 Oct 10;101(15):156101
18999616
Nat Nanotechnol. 2010 Mar;5(3):218-24
20154688
Micron. 2004;35(6):399-409
15120123