Homogeneous Nucleation and Forest Hardening Result in Thermal Hardening Phenomenon in Shock Loaded BCC Metals

TL;DR

This paper explains the thermal hardening phenomenon in shock-loaded BCC metals as a result of forest hardening caused by homogeneous nucleation, supported by simulations that match experimental data and predict behavior in other metals.

Contribution

It introduces a novel dislocation-based explanation for thermal hardening in BCC metals, emphasizing homogeneous nucleation and forest hardening over phonon drag.

Findings

Simulated results match experimental data quantitatively.

Predicted thermal hardening in Mo at higher temperatures.

Identified forest hardening as a key mechanism in thermal hardening.

Abstract

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.