Petrology Lunch - Zr-based metallic glasses under high-pressure: X-ray absorption experiment and molecular dynamics and DFT calculations - Przemysław Dzięgielewski

We are pleased to announce a Petrology Lunch with Przemysław Dzięgielewski on the topic of: Zr-based metallic glasses under high-pressure – X-ray absorption experiment and molecular dynamics and DFT calculations. 

Abstract:

The local atomic structure of metallic glasses (MGs) under high pressure remains undiscovered. Pressure provides significant changes in atomic structure, like polyamorphism (analog of well-known polymorphism in crystals) or devitrification. However, in molecular dynamics simulations for Zr-based metallic glasses above 50 GPa, we observe the existence of Zr-Zr pairs with significantly (c.a. 25%) shortened distances. In our understanding, the cause of their formation is a pressure-induced change in the electronic structure of Zr atoms – charge transfer from 5s to 4d states and vanishment above 50 GPa 5s orbital. As a result, the atomic radius of Zr atoms drops, which causes changes in the electrical properties of Zr-based MGs, ordering of local atomic structure, and stabilization of the amorphous phase.

In this talk, Przemysław will show the molecular dynamics predictions of the atomic structure of MGs and the X-ray absorption experimental results confirming the correctness of MD simulations. Przemysław will discuss the general features of X-ray absorption experiments and the possibility, limitations, and challenges of DFT calculations for disordered metallic systems under high pressure.

For Zoom link:

Meeting ID: 997 4444 5487

Passcode: 735859