Energy barriers associated with slip–twin interactions

The energetics of slip–coherent twin boundary (CTB) interactions are established under tensile deformation in face centered cubic (fcc) copper with molecular dynamics simulations, exploring the entire stereographic triangle. The CTBs serve as effective barriers in some crystal orientations more than others, consistent with experimental observations. The resulting dislocation structures upon slip–twin reactions are identified in terms of Burgers vector analysis. Visualization of the dislocation transmission, lock formation, dislocation incorporation to twin boundaries, dislocation multiplication at the matrix–twin interface and twin translation, growth, and contraction behaviors cover the most significant reactions that can physically occur providing a deeper understanding of the mechanical behavior of fcc alloys in the presence of twin boundaries. The results make a distinction between deformation and annealing twins interacting with incident dislocations and point to the considerable role both types of twins can play in strengthening of fcc metals.

[1]  C. B. Carter,et al.  Climb and glide of a/3〈111〉 dislocations in an aluminium Σ = 3 boundary , 1997 .

[2]  L. Rémy.  The interaction between slip and twinning systems and the influence of twinning on the mechanical behavior of fcc metals and alloys , 1981 .

[3]  I. M. Robertson,et al.  Grain Boundary Responses to Local and Applied Stress: An In Situ TEM Deformation Study , 2006 .

[4]  Yong-Wei Zhang,et al.  Dislocation–twin interaction mechanisms for ultrahigh strength and ductility in nanotwinned metals , 2009 .

[5]  C. Solenthaler,et al.  On the effect of deformation twinning on defect densities , 1997 .

[6]  L. Rémy.  Twin-twin interaction in FCC crystals , 1977 .

[7]  B. Escaig.  Sur le glissement dévié des dislocations dans la structure cubique à faces centrées , 1968 .

[8]  Ju Li,et al.  Analysis of shear deformations in Al and Cu: empirical potentials versus density functional theory , 2004 .

[9]  E. O. Hall.  Twinning and diffusionless transformations in metals , 1954 .

[10]  Ting Zhu,et al.  Interfacial plasticity governs strain rate sensitivity and ductility in nanostructured metals , 2007, Proceedings of the National Academy of Sciences.

[11]  Horst Hahn,et al.  The interaction mechanism of screw dislocations with coherent twin boundaries in different face-centred cubic metals , 2006 .

[12]  H. Maier,et al.  Deformation of single crystal hadfield steel by twinning and slip , 2000 .

[13]  K Schulten,et al.  VMD: visual molecular dynamics. , 1996, Journal of molecular graphics.

[14]  B. Kear,et al.  The dependence of the width of a dissociated dislocation on dislocation velocity , 1968 .

[15]  J. Evans.  Heterogeneous shear of a twin boundary in α-brass , 1974 .

[16]  D. Warner,et al.  An atomistic perspective on twinning phenomena in nano-enhanced fcc metals , 2008 .

[17]  L. Lim.  Slip-twin interactions in nickel at 573K at large strains , 1984 .

[18]  H. Sehitoglu,et al.  Strain hardening and heterogeneous deformation during twinning in Hadfield steel , 2010 .

[19]  Ting Zhu,et al.  Atomistic study of dislocation loop emission from a crack tip. , 2004, Physical review letters.

[20]  H. Van Swygenhoven,et al.  Stacking fault energies and slip in nanocrystalline metals , 2004, Nature materials.

[21]  G. M. Bond,et al.  DYNAMIC OBSERVATIONS OF THE TRANSFER OF SLIP ACROSS A GRAIN BOUNDARY , 1989 .

[22]  R. Asaro,et al.  Are rate sensitivity and strength effected by cross-slip in nano-twinned fcc metals , 2008 .

[23]  F. Frank,et al.  On deformation by twinning , 1955 .

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

[25]  E. Ma,et al.  In situ observation of twin boundary migration in copper with nanoscale twins during tensile deformation , 2007 .

[26]  H. Sehitoglu,et al.  Predicting twinning stress in fcc metals: Linking twin-energy pathways to twin nucleation , 2007 .

[27]  H. Maier,et al.  Competing mechanisms and modeling of deformation in austenitic stainless steel single crystals with and without nitrogen , 2001 .

[28]  G. Chin,et al.  Twin-slip, twin-twin and slip-twin interactions in Co-8 wt.% Fe alloy single crystals , 1973 .

[29]  T. H. Blewitt,et al.  Low‐Temperature Deformation of Copper Single Crystals , 1957 .

[30]  S. Papson,et al.  “Model” , 1981 .

[31]  C. Hartley,et al.  Reactions of slip dislocations at coherent twin boundaries in face‐centered‐cubic metals , 1978 .

[32]  S. V. Lubenets,et al.  Dynamics of twin layer broadening in indium , 1978 .

[33]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[34]  J. E. Flinn,et al.  Observation of twin boundary migration in copper during deformation , 2004 .

[35]  Han-Chen Huang,et al.  Novel deformation mechanism of twinned nanowires , 2006 .

[36]  H. Karnthaler,et al.  Glide dislocations on cube planes in a low stacking-fault energy alloy , 1983 .

[37]  T. Kizuka.  Atomistic Process of Twin-Boundary Migration Induced by Shear Deformation in Gold , 2007 .

[38]  N. Ghoniem,et al.  Stick–slip dynamics of coherent twin boundaries in copper , 2009 .

[39]  James R. Rice,et al.  Dislocation Nucleation from a Crack Tip" an Analysis Based on the Peierls Concept , 1991 .

[40]  Arthur F. Voter,et al.  Structural stability and lattice defects in copper: Ab initio , tight-binding, and embedded-atom calculations , 2001 .

[41]  Huajian Gao,et al.  Repulsive force between screw dislocation and coherent twin boundary in aluminum and copper , 2007 .

[42]  Andrew G. Glen,et al.  APPL , 2001 .

[43]  W. T. Roberts,et al.  Plastic deformation and phase transformation in textured austenitic stainless steel , 1970 .

[44]  G. Vellaikal.  Some observations on microyielding in copper polycrystals , 1969 .

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

[46]  Horst Hahn,et al.  Interactions between non-screw lattice dislocations and coherent twin boundaries in face-centered cubic metals , 2008 .

[47]  S. Mahajan,et al.  A thin twin and its interaction with a coherent twin boundary in copper , 1970 .

[48]  Sidney Yip,et al.  Ideal Pure Shear Strength of Aluminum and Copper , 2002, Science.

[49]  H. Karnthaler.  The study of glide on {001} planes in f.c.c. metals deformed at room temperature , 1978 .

[50]  A. D. Korotaev,et al.  Physics of the plasticity and fracture of high-strength crystals , 1992 .