Comment on "Effects of shear methods on shear strengths and deformation modes of two typical transition metal carbides and their unification"

TL;DR

This paper critiques a recent study on the shear behavior of transition metal carbides, highlighting fundamental flaws in their mechanical analysis due to inappropriate linear assumptions in a nonlinear deformation regime.

Contribution

It provides a critical analysis emphasizing the necessity of nonlinear deformation frameworks for accurate shear strength and deformation mode predictions in transition metal carbides.

Findings

Identifies flaws in the previous study's mechanical analysis.

Highlights the importance of nonlinear deformation considerations.

Questions the validity of prior shear strength results.

Abstract

Recently, Chuanying Li, Tao Fu, Xule Li, Hao Hu, and Xianghe Peng in [Phys. Rev. B 107, 224106] investigated the mechanical behavior of cubic HfC and TaC under simple shear (SS) and pure shear (PS) using first-principles calculations. Unfortunately, the paper contains some serious and fundamental flaws in the field of continuum mechanics and nanomechanics. The results presented appear to be qualitatively and quantitatively incorrect, they would be correct if we were in the small/linear deformation/strain regime, which we are not. A correct description therefore requires a finite/nonlinear deformation/strain apparatus.