Mechanically driven grain boundary relaxation: a mechanism for cyclic hardening in nanocrystalline Ni

Molecular dynamics simulations are used to show that cyclic mechanical loading can relax the non-equilibrium grain boundary (GB) structures of nanocrystalline metals by dissipating energy and reducing the average atomic energy of the system, leading to higher strengths. The GB processes that dominate deformation in these materials allow low-energy boundary configurations to be found through kinematically irreversible structural changes during cycling, which increases the subsequent resistance to plastic deformation.

[1]  R. Scattergood,et al.  Influence of Pb segregation on the deformation of nanocrystalline Al: Insights from molecular simulations , 2008 .

[2]  H. V. Swygenhoven,et al.  On non-equilibrium grain boundaries and their effect on thermal and mechanical behaviour: a molecular dynamics computer simulation , 2002 .

[3]  D. Jang,et al.  Grain-boundary relaxation and its effect on plasticity in nanocrystalline Fe , 2006 .

[4]  Z. Farhat,et al.  Effect of grain size on friction and wear of nanocrystalline aluminum , 1996 .

[5]  S. Suresh,et al.  Cyclic strain hardening of nanocrystalline nickel , 2006 .

[6]  V. Levitas.  High-pressure mechanochemistry: Conceptual multiscale theory and interpretation of experiments , 2003 .

[7]  J. Schiøtz.  Strain-induced coarsening in nanocrystalline metals under cyclic deformation , 2004 .

[8]  S. Brandstetter,et al.  From Micro‐ to Macroplasticity , 2006 .

[9]  T. Nieh,et al.  Effects of annealing and impurities on tensile properties of electrodeposited nanocrystalline Ni , 2004 .

[10]  Ju Li,et al.  AtomEye: an efficient atomistic configuration viewer , 2003 .

[11]  Robert J. Asaro,et al.  Toward a quantitative understanding of mechanical behavior of nanocrystalline metals , 2007 .

[12]  S. Suresh,et al.  Fatigue behavior of nanocrystalline metals and alloys , 2005 .

[13]  R. Averback,et al.  Yield strength in nanocrystalline Cu during high strain rate deformation , 2009 .

[14]  R. Averback,et al.  Quantitative description of plastic deformation in nanocrystalline Cu: Dislocation glide versus grain boundary sliding , 2008 .

[15]  Subra Suresh,et al.  Mechanical behavior of nanocrystalline metals and alloys , 2003 .

[16]  F. Delogu,et al.  Molecular dynamics investigation on the role of sliding interfaces and friction in the formation of amorphous phases , 2005 .

[17]  K. Jacobsen,et al.  Atomic-scale simulations of the mechanical deformation of nanocrystalline metals , 1998, cond-mat/9812102.

[18]  C. Schuh,et al.  Microstructural evolution during the heat treatment of nanocrystalline alloys , 2007 .

[19]  Remo Guidieri.  Res , 1995, RES: Anthropology and Aesthetics.

[20]  G. Palumbo,et al.  THE EFFECT OF GRAIN SIZE ON THE WEAR PROPERTIES OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL COATINGS , 2001 .

[21]  F. Delogu.  Dynamics of atomic species involved in shear-induced displacements at sliding symmetrical grain boundaries: a numerical study , 2007 .

[22]  H. V. Swygenhoven,et al.  Nucleation and propagation of dislocations in nanocrystalline fcc metals , 2006 .

[23]  R. Averback,et al.  Limits of hardness at the nanoscale: Molecular dynamics simulations , 2008 .

[24]  K. Jacobsen,et al.  A Maximum in the Strength of Nanocrystalline Copper , 2003, Science.

[25]  Michael J. Mehl,et al.  Interatomic potentials for monoatomic metals from experimental data and ab initio calculations , 1999 .

[26]  B. Boyce,et al.  A Review of Fatigue Behavior in Nanocrystalline Metals , 2010 .

[27]  Christopher A. Schuh,et al.  Sliding wear of nanocrystalline Ni-W: Structural evolution and the apparent breakdown of Archard scaling , 2010 .

[28]  K. Jacobsen,et al.  Softening of nanocrystalline metals at very small grain sizes , 1998, Nature.

[29]  J. Gilvarry.  The Lindemann and Grüneisen Laws , 1956 .

[30]  J. C. Hamilton,et al.  Dislocation nucleation and defect structure during surface indentation , 1998 .

[31]  M. Mayo,et al.  Structure and Mechanical Behavior of Bulk Nanocrystalline Materials , 1999 .

[32]  Steve Plimpton,et al.  Fast parallel algorithms for short-range molecular dynamics , 1993 .

[33]  Alfredo Caro,et al.  Grain-boundary structures in polycrystalline metals at the nanoscale , 2000 .