  Interpretation of thermal hardening phenomenon at high strain rate has
recently become a critical problem in shock wave physics. In this letter, this
problem is addressed from a viewpoint of dislocation generation, and a novel
conclusion is gained that forest hardening induced by homogeneous nucleation
(HN) results in thermal hardening behavior in a BCC metal significantly, apart
from phonon drag mechanism. Through numerical simulations with a dislocation
based crystal plasticity model, we have reproduced the experimental results
quantitatively and predicted a thermal hardening behavior in other BCC metals,
i.e., Mo, at higher temperature.
