Investigating amorphization as a deformation mechanism using a novel phase field model at the mesoscale

TL;DR

This paper presents a new phase-field model at the mesoscale that integrates elastoplastic theory to predict stress-induced amorphization in crystalline materials, providing insights into microstructural evolution under severe deformation.

Contribution

It introduces a novel phase-field model combining elastoplastic theory and stress-dependent transformation strains to simulate amorphization during deformation.

Findings

Predicts nucleation and growth of amorphous phases under high stress

Reproduces microstructural patterns like shear bands and surface amorphization

Shows avalanche-like amorphization and grain size effects

Abstract

Amorphization during severe plastic deformation has been observed in various crystalline materials, yet its underlying mechanisms remain poorly understood. This study introduces a novel phase-field model at the mesoscale, integrating elastoplastic theory with a deviatoric stress-dependent transformation strain tensor to capture stress-induced amorphization. The model enables quantitative predictions of amorphous phase nucleation and propagation under high stress, resolving distinctive microstructural patterns such as amorphous shear bands. Simulations reveal key phenomena, including avalanche-like amorphization, grain size effects, the Hall-Petch effect, and surface amorphization, consistent with experimental observations. By bridging phase-field methods with elastoplastic theory, this work provides a robust framework for studying amorphization as a deformation mechanism and offers valuable insights for designing materials resistant to extreme mechanical conditions.