A lattice fraction stress model with consideration of thermal activation

This paper systematically investigates the effect of temperature on lattice friction stress and develops a thermally activated dislocation slip mechanism. The findings reveal that temperature has a significant impact on dislocation slip behavior. At low temperatures, the contribution of thermal activation is minimal, leading to dislocation slip in an extended mode and resulting in higher lattice friction stress. In contrast, at high temperatures, the effect of thermal activation increases sharply, causing dislocations to slip in a full mode, thereby reducing lattice friction stress. Additionally, the influence of dislocation density, strain rate, and shear modulus on lattice friction stress is examined. Lattice friction stress decreases as dislocation density increases, but rises with higher strain rates and shear modulus. Overall, the model developed in this work provides a clearer understanding of the dislocation slip mechanism and sheds light on the underlying physical processes governing lattice friction stress.