RT Journal Article
SR Electronic
T1 Revealing Extraordinary Intrinsic Tensile Plasticity in Gradient Nano-Grained Copper
JF Science
JO Science
FD American Association for the Advancement of Science
SP 1587
OP 1590
DO 10.1126/science.1200177
VO 331
IS 6024
A1 Fang, T. H.
A1 Li, W. L.
A1 Tao, N. R.
A1 Lu, K.
YR 2011
UL http://science.sciencemag.org/content/331/6024/1587.abstract
AB Nano-grained (NG) metals are believed to be strong but intrinsically brittle: Free-standing NG metals usually exhibit a tensile uniform elongation of a few percent. When a NG copper film is confined by a coarse-grained (CG) copper substrate with a gradient grain-size transition, tensile plasticity can be achieved in the NG film where strain localization is suppressed. The gradient NG film exhibits a 10 times higher yield strength and a tensile plasticity comparable to that of the CG substrate and can sustain a tensile true strain exceeding 100% without cracking. A mechanically driven grain boundary migration process with a substantial concomitant grain growth dominates plastic deformation of the gradient NG structure. The extraordinary intrinsic plasticity of gradient NG structures offers their potential for use as advanced coatings of bulk materials.