Local structure order in Pd78Cu6Si16 liquid.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Understanding short-range order (SRO) in liquid alloys is crucial for predicting material properties.
• Palladium-copper-silicon (Pd-Cu-Si) alloys are of interest for their potential glass-forming abilities.

Purpose of the Study:

• To investigate the short-range order (SRO) in the Pd78Cu6Si16 liquid alloy.
• To elucidate the structural evolution and atomic arrangements upon cooling.

Main Methods:

• High energy X-ray diffraction for experimental structural analysis.
• Ab initio molecular dynamics (MD) simulations for theoretical modeling.
• Structure analysis using Honeycutt-Andersen index, Voronoi tessellation, and atomic cluster alignment.

Main Results:

• MD simulations accurately reproduced experimental pair correlation functions.
• Silicon atoms exhibit uniform distribution, while copper atoms tend to aggregate.
• Icosahedral and face-centered cubic SRO structures increase upon cooling.
• A dominant Pd-centered Pd9Si2 motif, similar to crystalline structures, was identified.
• Trigonal prism clusters, previously observed in Pd-based alloys, were confirmed.
• Copper-centered clusters are predominantly icosahedral, suggesting a role in glass formation.

Conclusions:

• The study provides detailed insights into the SRO of liquid Pd78Cu6Si16.
• Copper addition appears to enhance the glass-forming ability of these alloys.
• The findings contribute to the fundamental understanding of metallic glass structures.