Predicting shear transmission across grain boundaries with an iterative stress relief model

A new model is proposed to quantitatively predict the specific deformation system activity that accommodates impinging slip at a grain boundary. The model uses an iterative approach to sequentially determine (at most) three accommodating slip systems and their relative shear. The outcome of this iterative stress relief model is mainly controlled by the continuity of Burgers vector in the grain boundary and the iterative evolution of the impinging stress tensor at the grain boundary. The model was tested by comparing predictions with 22 distinct observations of shear accommodation in alpha-titanium quantified using orientation-informed slip trace analysis and atomic force microscopy. All 16 cases displaying a single accommodating system and four out of six observed cases with two accommodating systems were predicted correctly. Optimization of adjustable model parameters indicates that the local and global stresses are of comparable importance and jointly determine the accommodating systems and their activity. Moreover, the optimized ratios of critical resolved shear stress for the different deformation system families are consistent with literature values for alpha-titanium. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

A new model has been proposed to predict the specific deformation system activity at grain boundaries, with promising results in testing. The optimized parameters indicate that both local and global stresses play a role in determining the accommodating systems and their activity. The model's predictions align well with literature values for alpha-titanium.