Severe local lattice distortion in Zr- and/or Hf-containing refractory multi-principal element alloys

By Yang Tong, Shijun Zhao, Hongbin Bei, T. Egami, Yanwen Zhang, Fuxiang Zhang. 2020

154 citations recorded by the source corpus.

Abstract Whereas exceptional mechanical and radiation performances have been found in the emergent body-centered cubic (BCC) refractory multi-principal element alloys (RMPEAs), the importance of their complex atomic environment, reflecting diversity in atomic size and chemistry, has been largely unexplored at the atomic level. Here, we adopt a local structure approach based on the atomic pair distribution function measurements in combination with density functional theory (DFT) calculations to investigate a series of BCC RMPEAs. Our results demonstrate that all the analyzed RMPEAs exhibit local lattice distortions (LLD) to some extent, but a severe LLD, a breakdown of the 15% atomic size difference in Hume-Rothery rules, occurs only in the Zr- and/or Hf-containing RMPEAs. In addition, through the DFT calculations we show that charge transfer among the elements profoundly reduces the size mismatch effect in average to stabilize this energy-unfavorable severe LLD. The observed competitive coexistence between LLD and charge transfer demonstrates the importance of the electronic effects on the local environments in RMPEAs.

Subfields: Electrical and Electronic Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/e750bb0e26792d0f5c41a8e613b8301a2b8384b8

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In Mechanical Engineering

Citations in the corpus

Novel atomic-scale mechanism of incipient plasticity in a chemically complex CrCoNi medium-entropy alloy associated with inhomogeneity in local chemical environment (2020, background): “Actually, the lattice distortion often intertwine with the chemical effect from electronic interaction and necessitate inhomogeneous distribution of the elements, where there will be local preference (or avoidance) for bonding between certain nearestneighbor species [7, 38].”