Multiscale Modeling of Microstructure‐Property Relationships of Polycrystalline Metals during Thermo‐Mechanical Deformation

Abstract

The plastic deformation of polycrystalline metals is primarily carried by the crystallographic glide of dislocations and growth of deformation twins. According to the thermodynamic theory of slip, dislocation motion is thermally activated, while deformation twinning is an athermal process. Dislocations must overcome barriers in order to move, while twins must relax the stored energy while growing. These concepts define the critical activation stresses on a slip or twin crystallographic system and how they evolve with plastic strain. This article reviews recent advances in the development of a model for the critical activation stresses for thermally activated glide and the expansion of deformation twins, its implementation into polycrystal plasticity models, and several applications for predicting the constitutive response of polycrystalline metals. Calculations are performed for a range of polycrystalline metals differing in microstructural complexity and crystal structure. These examples include face-centered cubic AA6022-T4, IN718, Haynes 25, and pure Cu, body-centered cubic Nb, Ta, Ta-10W, and steel DP590, hexagonal close-packed pure Be, pure Zr, pure Ti, AZ31, Mg4Li, and orthorhombic U. Excellent agreement with experimental measurement are demonstrated in terms of texture, stress-strain response, and geometrical changes in the samples during deformation for all these metals.

Towards Manufacturing of Ultrafine-Laminated Structures in Metallic Tubes by Accumulative Extrusion Bonding

“…A frictional value of 0.025 is used between all sliding surfaces, which is consistent with the conclusions of [65], but slightly less than the values used in other research [66][67][68]. For comparison to rolling, this frictional value is less than the "normal" lubrication value of 11 as reported in [69].…”

Thermodynamic theory of crystal plasticity: Formulation and application to polycrystal fcc copper

“…As in many conventional theories of dislocation plasticity (e.g., Cheong and Busso, 2004;Hansen et al, 2013;Anand et al, 2015;Dequiedt et al, 2015;Zecevic et al, 2015;Knezevic and Beyerlein, 2018;Bronkhorst et al, 2019), the relevant internal state variable is the dislocation density ρ α on the different slip systems α. What distinguishes the present approach from conventional theories is that the evolution of the dislocation density are derived from energetic and entropic considerations alone, subject to the constraints of the first and second laws of thermodynamics.…”

Computational Homogenization of Polycrystals

“…Along these lines, Segurado et al (2012) developed a semiimplicit elasto-visco-plastic multiscale framework to simulate the plastic deformation of polycrystalline structures. This modelling framework have been later extended for different type crystals and applied to simulate thermomechanical processes on full components (Knezevic et al, 2016a;Zecevic et al, 2017a;Knezevic and Beyerlein, 2018). Due to the relevance of this work, the main equations of the framework developed in Segurado et al (2012) will be reviewed here, including some implementation aspects in a standard finite element code.…”