In-Situ TEM Observation of Solid-State Phase Evolution in High-Entropy Alloy Nanoparticles
Abstract
The emergence of new materials has gone beyond conventional design principles. Among them are high entropy alloys (HEAs), in which multiple metallic elements coexist within a single unit cell. In this case, each atomic position in a solid material has a different chemical environment, leading to configurational entropy as high as that in the fully random or melted state, which has been frozen to a solid solution. However, the behaviour of such alloy systems at pre-melting temperatures is largely unknown, where atoms gain sufficient mobility and time to rearrange, leading to an enthalpic rather than an entropic interplay. This study demonstrated the phase transformation of HEA nanoclusters (CoCrFeMnNi) under high-resolution transmission electron microscopy (HRTEM) at different temperatures, including room temperature (RT), 550 °C, and 850 °C. The clustered nanoparticles coarsen into larger clusters, accompanied by compositional heterogeneity due to surface and lattice diffusion. This experimental finding of atomic mobility was further corroborated using molecular dynamics, which provides a detailed mechanistic description.
Related
- Direct Observation of Dipolar-Driven Anisotropic Quantum Projection Noise in a Solid-State Spin Ensemble
- Direct observation of reversible ionic polarization at a buried solid-state battery interface
- Observation of measurement-induced localization phenomena in a solid-state spin system
- High-Entropy Alloy Aerogels with High-Density Solid–Solid Heterointerfaces for Alkaline Hydrogen Evolution
- Phase-Field Simulation of Dendrite Evolution in All-Solid-State Sodium Batteries during Cycling
BibTeX
@misc{katiyar2026insitu,
title = {{In-Situ TEM Observation of Solid-State Phase Evolution in High-Entropy Alloy Nanoparticles}},
author = {Nirmal Kumar Katiyar and Noorbasha Bhavani Sai and Guilherme Gurian Dariani and Douglas S. Galvao and Pulickel M. Ajayan and Pedro Alves da Silva Autreto and Sriram Vijayan and Chandra Sekhar Tiwary},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.14147},
eprint = {2610.14147},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.14147},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - In-Situ TEM Observation of Solid-State Phase Evolution in High-Entropy Alloy Nanoparticles
AU - Nirmal Kumar Katiyar
AU - Noorbasha Bhavani Sai
AU - Guilherme Gurian Dariani
AU - Douglas S. Galvao
AU - Pulickel M. Ajayan
AU - Pedro Alves da Silva Autreto
AU - Sriram Vijayan
AU - Chandra Sekhar Tiwary
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.14147
UR - https://arxiv.org/abs/2610.14147
AB - The emergence of new materials has gone beyond conventional design principles. Among them are high entropy alloys (HEAs), in which multiple metallic elements coexist within a single unit cell. In this case, each atomic position in a solid material has a different chemical environment, leading to configurational entropy as high as that in the fully random or melted state, which has been frozen to a solid solution. However, the behaviour of such alloy systems at pre-melting temperatures is largely unknown, where atoms gain sufficient mobility and time to rearrange, leading to an enthalpic rather than an entropic interplay. This study demonstrated the phase transformation of HEA nanoclusters (CoCrFeMnNi) under high-resolution transmission electron microscopy (HRTEM) at different temperatures, including room temperature (RT), 550 °C, and 850 °C. The clustered nanoparticles coarsen into larger clusters, accompanied by compositional heterogeneity due to surface and lattice diffusion. This experimental finding of atomic mobility was further corroborated using molecular dynamics, which provides a detailed mechanistic description.
ER -