SNIC
SUPR
SNIC SUPR
Ab initio crystal structure search and modeling of new High Entropy Ceramics
Dnr:

SNIC 2018/3-111

Type:

SNAC Medium

Principal Investigator:

Farid Akhtar

Affiliation:

LuleƄ tekniska universitet

Start Date:

2018-03-01

End Date:

2019-03-01

Primary Classification:

20501: Ceramics

Secondary Classification:

10304: Condensed Matter Physics

Tertiary Classification:

21001: Nano-technology

Allocation

Abstract

The applicant Farid Akhtar joined the Engineering Materials group at LuleƄ University of Technology (LTU) in March 2014, as part of the Division of Materials Science. His research focuses on the development of new materials with tailored properties for high temperature applications. Of special interest is the new class of high entropy alloys, called high entropy ceramics (HECs). This new class of materials are multiple component systems consisting of several ceramic compounds such metallic oxides, nitrides or carbides. HECs show superior mechanical properties including high strength, high wear resistance, good corrosion and oxidation resistance over conventional alloys, especially at elevated temperatures. For this project studies of new HECs will be done by combining theoretical modeling and experiments. The experimental part carried out by PhD student Hanzhu Zhang (Engineering Materials, LTU) and the theoretical modeling by PhD student Daniel Hedman (Applied Physics, LTU). The theoretical part will focus on modeling HECs at the atomic level using Density Functional Theory (DFT). Crystal structures for new HECs will be predicted from different chemical compositions using particle swarm optimization (PSO) together with DFT. PSO can overcome large energy barriers and handle very large search spaces, making it ideal for complex multicomponent systems. To calculate reliable properties for HECs (lattice parameters, formation enthalpies, electrical and mechanical properties, etc.) using DFT, the PSO predicted HECs will be modeled using Special Quasirandom Structures (SQS). By combining theoretical modelling and experiments we aim to increase the understanding of HECs, their properties, formation and how to characterize them.