Investigation of the Pd (1− x ) Zn x alloy phase diagram using ab initio modelling approaches

Kabalan, Lara, Kowalec, Igor, Rigamonti, Santiago, Troppenz, Maria, Draxl, Claudia, Catlow, C Richard ORCID: https://orcid.org/0000-0002-1341-1541 and Logsdail, Andrew J ORCID: https://orcid.org/0000-0002-2277-415X 2023. Investigation of the Pd (1− x ) Zn x alloy phase diagram using ab initio modelling approaches. Journal of Physics: Condensed Matter 35 (40) , 405402. 10.1088/1361-648x/ace01a

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Abstract

The identification of the stable phases in alloy materials is challenging because composition affects the structural stability of different intermediate phases. Computational simulation, via multiscale modelling approaches, can significantly accelerate the exploration of phase space and help to identify stable phases. Here, we apply such new approaches to understand the complex phase diagram of binary alloys of PdZn, with the relative stability of structural polymorphs considered through application of density functional theory coupled with cluster expansion (CE). The experimental phase diagram has several competing crystal structures, and we focus on three different closed-packed phases that are commonly observed for PdZn, namely the face-centred cubic (FCC), body-centred tetragonal (BCT) and hexagonal close packed (HCP), to identify their respective stability ranges. Our multiscale approach confirms a narrow range of stability for the BCT mixed alloy, within the Zn concentration range from 43.75% to 50%, which aligns with experimental observations. We subsequently use CE to show that the phases are competitive across all concentrations, but with the FCC alloy phase favoured for Zn concentrations below 43.75%, and that the HCP structure favoured for Zn-rich concentrations. Our methodology and results provide a platform for future investigations of PdZn and other close-packed alloy systems with multiscale modelling techniques.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Cardiff Catalysis Institute (CCI) Chemistry
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0, Type: cc-by
Publisher:	IOP Publishing
ISSN:	0953-8984
Funders:	EPSRC, UKRI
Date of First Compliant Deposit:	10 July 2023
Date of Acceptance:	20 June 2023
Last Modified:	17 Sep 2023 20:28
URI:	https://orca.cardiff.ac.uk/id/eprint/160923

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