Landau modeling of dynamical nucleation of martensite at grain boundaries under local stress

TL;DR

This paper models the dynamical nucleation of martensite at grain boundaries under local stress using Landau energetics and Lagrange-Rayleigh dynamics, revealing key nucleation sites and phase diagrams.

Contribution

It introduces a simulation approach combining Landau energetics with Lagrange-Rayleigh dynamics to study martensite nucleation at grain boundaries under local stress.

Findings

High angle grain boundaries and triple junctions serve as favorable nucleation sites.

The model predicts the phase diagram of martensite nucleation modes.

Local stress influences the nucleation process and site selection.

Abstract

The dynamical nucleation of martensite in polycrystals is simulated by means of Lagrange-Rayleigh dynamics with Landau energetics, which is capable of obtaining the local stress as a result of the interplay of the potential of transformation and external loadings. By monitoring the patio-temporal distribution of the strain in response to the local stress, we demonstrate that the postcursors, high angle grain boundaries and triple junctions act as favorable heterogeneous nucleation sites corresponding to different loading and cooling conditions, and predict the phase diagram of the nucleation mode of martensite.