Misorientation and grain boundary orientation dependent grain boundary response in polycrystalline plasticity

This paper studies the evolution of intergranular localization and stress concentration in three dimensional micron sized specimens through the Gurtin grain boundary model (J Mech Phys Solids 56:640-662, 2008) incorporated into a three dimensional higher-order strain gradient crystal plasticity framework (Yalcinkaya et al. in Int J Solids Struct 49:2625-2636, 2012). The study addresses continuum scale dislocation-grain boundary interactions where the effect of crystal orientation mismatch and grain boundary orientation are taken into account through the grain boundary model in polycrystalline metallic specimens. Due to the higher-order nature of the model, a mixed finite element formulation is used to discretize the problem in which both displacements and plastic slips are considered as primary variables. For the treatment of grain boundaries within the solution algorithm, an interface element is formulated and implemented together with the bulk plasticity model. The capabilities of the framework is demonstrated through 3D polycrystalline examples considering grain boundary conditions, grain boundary strength, the orientation distribution and the specimen size. A detailed grain boundary condition and stress concentration analysis is presented. The advantages and the disadvantages of the model is discussed in detail through numerical examples.


Covalent and noncovalent functionalization of pristine and defective graphene by cyclohexane and dehydrogenated derivatives
Sayin, Ceren Sibel; Toffoli, Daniele; Toffoli, Hande (2015-10-01)
The interaction of cyclohexane (C6H12), cyclohexyl (C6H11*) and cyclohexene (C6H10) with both pristine and defective graphene (single vacancy and a carbon adatom), is systematically investigated within the density functional theory framework. C6H12 physisorbs on both pristine and defective graphene while C6H10 chemisorbs on graphene in the presence of an adatom. The C6H11* radical binds covalently with the graphene substrate in all adsorption geometries considered.
Dielectric and Thermal Effects on the Optical Properties of Natural Dyes: A Case Study on Solvated Cyanin
Malcıoğlu, Osman Barış; Gebauer, Ralph; Varsano, Daniele; Baroni, Stefano (2011-10-05)
The optical properties of the flavylium state of the cyanin dye are simulated numerically by combining Car-Parrinello molecular dynamics and linear-response time-dependent density functional theory calculations. The spectrum of the dye calculated in the gas phase is characterized by two peaks in the yellow and in the blue (green and violet), using a GGA-PBE (hybrid-B3LYP) DFT functional, which would bring about a greenish (bright orange) color incompatible with the dark purple hue observed in nature. Descri...
Modeling of dislocation-grain boundary interactions in a strain gradient crystal plasticity framework
ÖZDEMİR, İZZET; Yalçınkaya, Tuncay (Springer Science and Business Media LLC, 2014-08-01)
This paper focuses on the continuum scale modeling of dislocation-grain boundary interactions and enriches a particular strain gradient crystal plasticity formulation (convex counter-part of Yal double dagger inkaya et al., J Mech Phys Solids 59:1-17, 2011; Int J Solids Struct 49:2625-2636, 2012) by incorporating explicitly the effect of grain boundaries on the plastic slip evolution. Within the framework of continuum thermodynamics, a consistent extension of the model is presented and a potential type non-...
Intrinsic and Statistical Size Effects in Microforming
Yalçınkaya, Tuncay; Simonovski, Igor; ÖZDEMİR, İZZET (2017-04-28)
This paper analyzes the intrinsic (grain size dependent) and the statistical (grain number and orientation distribution dependent) size effects of micron level polycrystalline metallic specimens under plastic deformation through a strain gradient crystal plasticity framework. The macroscopic and local behavior of specimens from very limited number of grains to high number of grains are studied and the results are discussed in detail taking into account different boundary conditions.
Optoelectrochemical properties of the copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole monomer with 3,4-ethylenedioxythiophene
AK, Metin; Tanyeli, Cihangir; Akhmedo, Dris M.; Toppare, Levent Kamil (Elsevier BV, 2008-04-30)
Copolymer of 2,5-di(4-methylthiophen-2-yl)-1-(4-nitrophenyl)-1H-pyrrole (MTNP) with 3,4-ethylene dioxythiophene (EDOT) was electro-chemically synthesized and characterized via cyclic voltammetry, Fourier Transform Infrared spectroscopy, Scanning Electron Microscopy, conductivity measurements. Spectroelectrochemical investigations showed that resulting copolymer film has distinct electrochromic properties. It has five different colors (dark purple, red, light grey, green, blue). At the neutral state m due to...
Citation Formats
T. Yalçınkaya and İ. T. Tandoğan, “Misorientation and grain boundary orientation dependent grain boundary response in polycrystalline plasticity,” COMPUTATIONAL MECHANICS, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/89285.