Increasing strain rates in typical steel grades lead to enhanced yield and tensile strength due to the dynamics of dislocation generation and movement. As strain rates rise, the generation of dislocations increases, leading to a higher dislocation density within the material. This accumulation of dislocations contributes to work hardening, as they pile up and hinder further dislocation motion. The effectiveness of this process is contingent on the rate at which dislocations diffuse through the crystal structure to grain boundaries. If dislocation generation outpaces their diffusion, the resulting high dislocation density significantly strengthens the material. Additionally, while dislocations can cancel each other out, insufficient diffusion at elevated strain rates prevents this cancellation, further contributing to increased strength. The phenomenon is not limited to steel but is also observed in various metals and polymers. For a deeper understanding, reference to the paper by Kenneth Hoyt Adams is suggested.
