[Paper Review] On the configurational force associated with blocked slip bands at grain boundaries in α-Ti

Abdalrhaman Koko|arXiv (Cornell University)|Mar 25, 2026

Microstructure and mechanical properties0 citations

TL;DR

The paper applies a configurational force framework to HR-EBSD measurements of a blocked slip band in α-Ti to quantify the energetic driving force of slip-band blockage at grain boundaries, linking local stress localisation to potential extension directions in neighboring grains.

ABSTRACT

Grain boundaries can block slip-band propagation and generate intense local stress and strain fields that influence subsequent deformation and damage initiation in polycrystalline metals. Conventional geometric criteria, such as Schmid factor and slip-transfer parameters, describe crystallographic compatibility but do not quantify the energetic severity of a blocked slip event. Here, we apply a configurational force framework to high-angular-resolution electron backscatter diffraction (HR-EBSD) measurements obtained from a blocked slip band in commercially pure titanium. By evaluating a J-type equivalent domain integral from the measured elastic field, we quantify both the magnitude and directional dependence of the local energetic driving force associated with the stress localisation; thus, providing an energetic descriptor of the tendency for deformation to extend into the neighbouring grain. The results show a marked decoupling between conventional geometric metrics and the configurational force response, indicating that the local stress-localisation geometry strongly influences which crystallographically admissible extension directions in the neighbouring grain are energetically favoured. The framework provides a physically grounded basis for quantifying blocked-slip severity and for motivating future in situ studies aimed at defining a critical transfer threshold for transfer or cracking.

Motivation & Objective

• Motivate the need for an energetic descriptor of blocked-slip events beyond geometric criteria like Schmid factor.
• Apply a configurational force framework to experimental HR-EBSD data to quantify local driving forces.
• Assess how local stress localisation influences energetically favored transfer or cracking directions across grain boundaries.

Proposed method

• Compute a J-type equivalent domain integral from the measured elastic field to obtain the configurational force.
• Use high-angular-resolution electron backscatter diffraction (HR-EBSD) measurements of a blocked slip band in commercially pure titanium as the data source.
• Analyze magnitude and directional dependence of the local energetic driving force associated with stress localisation.
• Compare configurational-force results with conventional geometric metrics to assess decoupling between geometry and energetics.

Experimental results

Research questions

• RQ1 Can configurational forces derived from the elastic field quantify the energetic severity of blocked slip events at grain boundaries?
• RQ2 How does local stress localisation influence energetically favored extension directions in neighbouring grains compared to traditional geometric criteria?
• RQ3 Do geometric metrics reliably predict the energetic propensity for slip transfer or cracking across grain boundaries?

Key findings

• There is a marked decoupling between conventional geometric metrics and the configurational force response.
• Local stress-localisation geometry strongly influences which crystallographically admissible extension directions are energetically favoured.
• The framework provides a physically grounded basis for quantifying blocked-slip severity and motivating future in situ studies.