A multiscale phenomenological constitutive model for strain rate dependent tensile ductility in nanocrystalline metals

Abstract

A variational multiscale constitutive model that accounts for strain rate dependent ductility of nanocrystalline materials during intergranular failure has been presented. The presented model is an extension of the previous work [1], in which a nanocrystalline material is modelled as two-phase with grain interior being modelled using crystal plasticity theory while grain boundary affected zone using porous plasticity model which accounts for ductile damage due to void growth and coalescence. The model capability of capturing the strain rate dependent deformation and failure has been demonstrated through validations against uniaxial test data taken from literature. The validated results show a good agreement between experimental and simulated response.

A CPFEM based study to understand the void growth in high strength dual-phase titanium alloy (Ti-10V-2Fe-3Al)

“…Tekoğlu, Hutchinson and Pardoen (2015) also studied the effects of strain localisation on the void coalescence under different stress states using unit cell with void simulations. Siddiq & El Sayed (2015) included the effects of strain rate in the previously developed variational void coalescence model. Song and Castañeda (2017, 2018 presented a macroscale homogenisation-based constitutive model for porous polycrystalline material.…”

A multiscale FEM-MD coupling method for investigation into atomistic-scale deformation mechanisms of nanocrystalline metals under continuum-scale deformation

“…Some other multiscale studies have employed a crystal plasticity model to take into account the generation and the glide of dislocations in the grain interior and have shown the capability of capturing typical characteristic phenomena of nanocrystalline metals, such as the inverse Hall-Petch effect or predicting damage and fracture [26][27][28]. The multiscale constitutive model that uses plastic energy dissipation to identify parameters related to microscopic phenomena showed good agreement with experimental data [29].…”