Grain boundary grooving in bi-crystal thin films induced by surface drift-diffusion driven by capillary forces and applied uniaxial tensile stresses

2012-01-01
Akyildiz, Oncu
ÖREN, ERSİN EMRE
Ogurtani, Tarik Omer
Grain boundary (GB) grooving, induced by surface drift-diffusion and driven by the combined actions of capillary forces and applied uniaxial tensile stresses, is investigated in bi-crystal thin films using self-consistent dynamical computer simulations. A physico-mathematical model, based on the irreversible thermodynamics treatment of surfaces and interfaces with singularities allowed auto-control of the otherwise free-motion of the triple junction at the intersection of the grooving surface and the GB, without having any a priori assumption on the equilibrium dihedral angles. In the present theory, the generalised driving forces for stress-induced surface drift-diffusion arise not only from the usual elastic strain energy density (ESED), but also much stronger elastic dipole tensor interactions (EDTI) between the applied stress field and the mobile atomic species situated at the surface layer and in the GB regions. Accelerated groove-deepening kinetics shows that the surface drift-diffusion enhanced by the applied uniaxial tensile stresses through EDTI is dominant over the GB flux leakage at the triple junction. At high uniaxial stress levels (>= 500MPa for a 100-nm thick copper film), a sequential time-frame for micro-crack nucleation and growth is recorded just before specimen failure took place. These non-equilibrium thermokinetics discoveries (kinetics and energetics) contradict or at least do not support the hypothesis of the steady-state diffusive GB micro-crack formation and propagation due to 'constant' flux drainage through GB enhanced by tensile stresses acting normal to it.
PHILOSOPHICAL MAGAZINE

Suggestions

Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations
Akyildiz, Oncu; Ogurtani, Tarik Omer (AIP Publishing, 2011-08-15)
The morphological evolution kinetics of a bicrystal thin film induced by anisotropic surface drift diffusion and driven by the applied electrostatic field is investigated via self consistent dynamical computer simulations. The physico-mathematical model, which is based upon the irreversible thermodynamic treatment of surfaces and interfaces with singularities [T. O. Ogurtani, J. Chem. Phys. 124, 144706 (2006)], provided us with auto-control on the otherwise free-motion of the triple junction at the intersec...
Grain-Scale Investigations of Deformation Heterogeneities in Aluminum Alloys
GÜLER, BARAN; Simsek, Ulke; Yalçınkaya, Tuncay; EFE, MERT (2018-04-25)
The an isotropic deformation of Aluminum alloys at micron scale exhibits localized deformation, which has negative implications on the macroscale mechanical and forming behavior. The scope of this work is twofold. Firstly, micro-scale deformation heterogeneities affecting forming behavior of aluminum alloys is investigated through experimental microstructure analysis at large strains and various strain paths. The effects of initial texture, local grain misorientation, and strain paths on the strain localiza...
Grain boundary grooving and cathode voiding in bamboo-like metallic interconnects by surface drift diffusion under the capillary and electromigration forces
Ogurtani, TO; Akyildiz, O (AIP Publishing, 2005-05-01)
The process of grain boundary (GB) grooving and cathode voiding in sandwich type thin film bamboo lines are simulated by introducing a mathematical model, which flows from the fundamental postulates of irreversible thermodynamics. In the absence of the electric field, the computer studies on the triple junction kinetics show that it obeys the first order reaction kinetics at early transient stage, which is followed by the familiar time law as (t) over bar (1/4), at the steady state regime. The applied elect...
Morphological evolution of edge-hillocks on single-crystal films having anisotropic drift-diffusion under the capillary and electromigration forces
Ogurtani, Tarik Omer; Celik, Aytac; Oren, Ersin Emre (Elsevier BV, 2007-01-22)
The morphological evolution of hillocks at the unpassivated sidewalls of single-crystal metallic thin film interconnects is investigated via computer simulations using the free-moving boundary value problem. The effect of drift-diffusion anisotropy on the development of surface topographical scenarios is fully explored under the action of electromigration and capillary forces, utilizing numerous combinations of the surface texture, the drift-diffusion anisotropy and the direction of the applied electric fie...
Computational and experimental study of high-speed impact of metallic Taylor cylinders
Konokman, H. Emrah; Coruh, M. Murat; Kayran, Altan (Springer Science and Business Media LLC, 2011-08-01)
High-speed impact of metallic Taylor cylinders is investigated computationally and experimentally. On the computational side, a modular explicit finite element hydrocode based on updated Lagrangian formulation is developed. A non-classical contour integration is employed to calculate the nodal forces in the constant strain axisymmetric triangular elements. Cell and nodal averaging of volumetric strain formulations are implemented on different mesh architectures to reduce the incompressibility constraints an...
Citation Formats
O. Akyildiz, E. E. ÖREN, and T. O. Ogurtani, “Grain boundary grooving in bi-crystal thin films induced by surface drift-diffusion driven by capillary forces and applied uniaxial tensile stresses,” PHILOSOPHICAL MAGAZINE, pp. 804–829, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/67048.