Role of nanoscale Cu/Ta interfaces on the shock compression and spall failure of nanocrystalline Cu/Ta systems at the atomic scales
Molecular dynamics (MD) simulations are used to investigate the role of size and distribution of nanoscale Cu/Ta interfaces on the nucleation and evolution of defects during shock loading and spall failure of nanocrystalline (nc) Cu/Ta alloys. Cu/Ta interfaces are introduced through the embedding of Ta clusters in nc-Cu matrix. The phase stability of the embedded Ta clusters either as FCC or BCC clusters is first investigated and reveals that the FCC Ta clusters have a lower energy for diameters less than 4 nm, whereas the BCC Ta clusters have a lower energy for the larger diameters. The shock simulations are then carried out for Ta clusters with an average diameter of 1 and 3 nm and concentrations of 3.0, 6.3 and 10.0% to investigate the role of size and distribution of Cu/Ta interfaces (due to presence of clusters) on the nucleation and evolution of dislocations as well as the spall strength of the alloy. The MD simulations indicate that the Cu/Ta interfaces reduce the capability of nc-Cu to accommodate plasticity through nucleation of dislocations and create void nucleation sites during spallation. The MD simulations further reveal that the impact strengthening effects due to the presence of nanoscale Cu/Ta interfaces are strongly dependent upon the size and distribution of Ta clusters, as well as the grain size of Cu matrix. Smaller size of interfaces (cluster size), higher concentration of Ta (smaller spacing between interfaces) and larger matrix grain size render higher spall strengths of nc-Cu/Ta microstructures.
This material is based upon work supported by the National Science Foundation (NSF) CMMI Grant-1454547.
Compliance with ethical standards
Conflict of interest
All the authors declare that they have no conflict of interest.
- 16.Minich RW, Cazamias JU, Kumar M et al (2004) Effect of microstructural length scales on spall behavior of copper. Metall Trans A 35A:2664–2673Google Scholar
- 19.National Research Council (2011) Opportunities in protection materials science and technology for future army applications. The National Academies Press, Washington, DCGoogle Scholar
- 55.Dongare AM, LaMattina B, Irving DL, Rajendran AM, Zikry MA, Brenner DW (2012) An angular-dependent embedded atom method (a-eam) interatomic potential to model thermodynamic and mechanical behavior of Al/Si composite materials. Model Simul Mater Sci Eng 20:035007. https://doi.org/10.1088/0965-0393/20/3/035007 CrossRefGoogle Scholar
- 58.Chen J, Tschopp MA, Dongare AM, Shock wave propagation and spall failure of nanocrystalline Cu/Ta alloys: effect of ta in solid-solution. J Appl Phys (submitted, in review)Google Scholar