[Paper Review] On the Intrinsic Link between Gradient Strengthening and Passivation Onset in Single Crystal Plasticity

H. Pouriayevali|arXiv (Cornell University)|Mar 2, 2026

Nonlocal and gradient elasticity in micro/nano structures0 citations

TL;DR

The paper develops a thermodynamically consistent gradient crystal plasticity framework to show that size-dependent yield strengthening is intrinsically linked to passivation-type boundary effects, revealing a strong dissipative gradient influence.

ABSTRACT

A finite-deformation framework for gradient crystal plasticity is developed within a thermodynamically consistent setting grounded in Gurtin's power-conjugate formulation. The model introduces a flow rule that accounts explicitly for both energetic and dissipative microstress contributions. Numerical simulations are performed to investigate the response of single crystals subjected to passivation-type boundary constraints. The results reveal that constitutive laws capable of reproducing size-dependent strengthening at the onset of plastic flow simultaneously generate a pronounced, nearly elastic-type response when passivation is imposed. These findings establish a fundamental connection between gradient-induced yield strengthening and boundary-driven elevation of the mechanical response, highlighting the essential influence of dissipative gradient effects.

Motivation & Objective

• Motivate a finite-deformation gradient plasticity framework that is consistent with Gurtin's power-conjugate formulation.
• Explicitly separate energetic and dissipative microstress contributions in the flow rule.
• Investigate how passivation-type boundary constraints influence the plastic response of single crystals.

Proposed method

• Develop a finite-deformation gradient crystal plasticity model framed thermodynamically.
• Introduce a flow rule that includes energetic and dissipative microstress contributions.
• Perform numerical simulations with passivation-type boundary constraints to test constitutive behavior.
• Analyze how gradient effects modify yield strengthening and boundary response.

Experimental results

Research questions

• RQ1 Does gradient-strengthening behavior at plastic onset persist when passivation constraints are imposed?
• RQ2 What is the role of dissipative gradient effects in elevating the mechanical response under boundary constraints?
• RQ3 Can constitutive laws that capture size-dependent strengthening simultaneously reproduce a near-elastic response under passivation?
• RQ4 What fundamental link exists between gradient-induced yield strengthening and boundary-driven response in single crystals?

Key findings

• Constitutive laws that reproduce gradient-strengthening at yield onset also generate a pronounced, nearly elastic-type response under passivation constraints.
• There exists a fundamental connection between gradient-induced yield strengthening and boundary-driven elevation of the mechanical response.
• Dissipative gradient effects play an essential role in coupling gradient strengthening with passivation onset in the model.
• The results highlight how boundary conditions interact with gradient plasticity to shape the observed mechanical response.