Temperature-induced structural evolution in liquid Bi86.8Au13.2 alloy

Area of Science:

• Materials Science
• Condensed Matter Physics
• Physical Chemistry

Background:

• Understanding the structural evolution of liquid alloys is crucial for materials design.
• Bismuth-gold (Bi-Au) alloys exhibit complex phase behavior.
• Liquid-to-liquid transitions offer insights into atomic ordering in disordered systems.

Purpose of the Study:

• To investigate the temperature-induced structural changes in a liquid Bi86.8Au13.2 alloy.
• To elucidate the mechanism behind the observed liquid-to-liquid crossover (LLC).
• To explore the relationship between LLC and local atomic packing.

Main Methods:

• In situ high-energy x-ray diffraction (XRD).
• Ab initio molecular dynamics (AIMD) simulations.
• Analysis of pair distribution function (g(r)).

Main Results:

• A reversible liquid-to-liquid crossover (LLC) was identified in liquid Bi86.8Au13.2 alloy between 700-800 K.
• The LLC is attributed to decreased Au-Au coordination and increased Bi-X coordination (X=Bi, Au) at short ranges.
• An extra subpeak in g(r) suggests a link to low-temperature liquid structures resembling solid Au2Bi and Bi phases.

Conclusions:

• The study reveals a novel LLC in a Bi-Au liquid alloy.
• Structural heredity plays a role in the liquid-to-liquid transition.
• The findings provide a deeper understanding of atomic-level rearrangements in liquid alloys.