|About this Abstract
|MS&T23: Materials Science & Technology
|Interface-mediated Phenomena in Structural Materials
|Atomistic Dynamics of Pre-existing Edge Dislocations in FCC Metals at High Strain Rates: Arrhenius to Non-Arrhenius Transition
|Akarsh Verma, Sandeep Kumar Singh, Shigenobu Ogata
|On-Site Speaker (Planned)
In this work, authors have conducted molecular dynamics simulations to evaluate edge dislocation velocity in face-centered cubic metals. Generally, dislocation migration is thought to be a thermally-activated (Arrhenius) phenomenon; but interestingly, we have predicted that for higher strain rates, all elements show an anti-thermal (non-Arrhenius) behavior. Phonon scattering is chief reason behind this compelling behavior of dislocation drag. At relatively lower strain rates, we perceived a transition from thermally activated to anti-thermal dislocation migration behavior at certain characteristic temperatures. We anticipate that with further lower strain rates, transitioning (thermally-activated to anti-thermal) temperatures would become even higher. Hence, thermal fluctuations dominate at low strain rates and phonon drag mechanism at high strain rates. Enough evidence from the literature is provided to support our computational predictions. This high strain rate study may also give an insight into armor and protective structures, with a boost to the systems industry to design next-generation materials.