Phase Changes of Multielemental Alloy Nanoparticles at Elevated Temperatures

Area of Science:

• Materials Science
• Nanotechnology
• Catalysis

Background:

• Multielemental alloy (MEA) nanomaterials, including medium and high entropy alloys, offer significant catalytic potential due to their complex structures.
• Factors like temperature, stress, and irradiation can alter MEA structures, impacting their performance in demanding applications.

Purpose of the Study:

• To investigate the atomic-scale effects of high temperatures on quaternary PtPdFeCo multielemental alloy nanoparticles.
• To compare the thermal behavior of quaternary PtPdFeCo MEAs with binary PtFe nanoalloys.

Main Methods:

• Atomic-scale investigation of multielemental alloy nanoparticles under elevated temperatures (room temperature to 1073 K).
• Density Functional Theory (DFT) calculations to rationalize observed phase transitions.
• Analysis of elemental migration energies and bonding energies to understand transition mechanisms.

Main Results:

• Quaternary PtPdFeCo nanoparticles exhibit reversible phase transitions between solid solution and intermetallic phases at high temperatures.
• Binary PtFe nanoalloys show a one-way transition from solid solution to intermetallic phases.
• DFT studies revealed that element migration energies and bonding energies dictate the direction and nature of phase transitions.

Conclusions:

• The study elucidates the temperature-dependent phase transition behavior of nano-multielemental alloys.
• Findings provide critical insights into the design and application of MEAs in high-temperature environments.
• Understanding elemental interactions is crucial for predicting and controlling alloy behavior under thermal stress.