Anomalous Plasticity of Body-Centered-Cubic Crystals with Non-Schmid Effect

TL;DR

This paper develops a continuum mechanical model for anomalous plasticity in BCC crystals with non-Schmid effects, validated against experimental data, highlighting the limitations of classical models in capturing abnormal deformation behaviors.

Contribution

It introduces a novel single crystal constitutive model incorporating non-Schmid projection tensors to better describe plastic flow in BCC crystals.

Findings

Model captures anomalous plastic flow features in BCC crystals.

Comparison with experiments validates the non-Schmid effects in deformation.

Provides physical insights into deformation mechanisms at low temperatures.

Abstract

Plastic deformations in body-centered-cubic (BCC) crystals have been of critical importance in diverse engineering and manufacturing contexts across length scales. Numerous experiments and atomistic simulations on BCC crystals reveal that classical crystal plasticity models with the Schmid law are not adequate to account for abnormal plastic deformations often found in these crystals. In this paper, we address a continuum mechanical treatment of anomalous plasticity in BCC crystals exhibiting non-Schmid effects, inspired from atomistic simulations recently reported. Specifically, anomalous features of plastic flows are addressed in conjunction with a single crystal constitutive model involving two non-Schmid projection tensors widely accepted for representing non-glide components of an applied stress tensor. Further, modeling results on a representative BCC single crystal (tantalum) are presented and compared to experimental data at a range of low temperatures to provide physical insight into deformation mechanisms in these crystals with non-Schmid effects.