Campus Units

Aerospace Engineering, Mechanical Engineering, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

9-1-2020

Journal or Book Title

Acta Materialia

Volume

196

First Page

430

Last Page

443

DOI

10.1016/j.actamat.2020.06.059

Abstract

A scale-independent model for the interaction between multivariant phase transformations (PTs) and discrete shear bands is advanced and utilized to simulate plastic strain-induced PTs at high pressure. The model includes a scale-free phase-field theory for martensitic PTs. The localized shear bands are introduced via a contact problem formulation. That is, the continuous distribution of sliding displacements along the prescribed slip surfaces is modeled to reproduce the plastic-strain-induced stress concentrators necessary for nucleation of a high-pressure phase (HPP). The strain-induced PTs in the bi/polycrystalline samples subjected to compression and shear are studied. The simulations show a severe reduction in the PT pressure by the plastic shear in comparison to a hydrostatic condition, even below the phase equilibrium pressure, like in known experiments. Transformation kinetics versus shear strain for each martensitic variant and the volume fraction of the HPP in individual grains and the entire aggregate are determined. The stationary volume fraction of the HPP is the same for polycrystals consisting of 13 and 38 grains, and a further shearing does not cause PT. The local phase equilibrium condition based on the transformation-work criterion is satisfied at almost all stationary phase interfaces. A similar phase equilibrium condition in terms of stresses averaged over the entire polycrystal or HPP is fulfilled. These results are important for the development of the microscale kinetic equations and modeling the sample behavior in traditional and rotational diamond anvils during the high-pressure torsion, ball milling, friction, and other deformation-transformation processes.

Comments

This is a manuscript of an article published as Esfahani, S. Ehsan, Iman Ghamarian, and Valery I. Levitas. "Strain-induced multivariant martensitic transformations: A scale-independent simulation of interaction between localized shear bands and microstructure." Acta Materialia 196 (2020): 430-443. DOI: 10.1016/j.actamat.2020.06.059. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Acta Materialia Inc.

Language

en

File Format

application/pdf

Available for download on Thursday, July 07, 2022

Published Version

Share

COinS