Xin Liu^1*, William Curtin¹

1 Laboratory for Multiscale Mechanics Modeling, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Vaud, Switzerland

* Corresponding authors emails: xin.liu@epfl.ch

DOI10.24435/materialscloud:kz-b7 [version v1]

Publication date: Nov 30, 2023

How to cite this record

Xin Liu, William Curtin, Atomistic simulations reveal strength reductions due to short-range order in alloys, Materials Cloud Archive 2023.184 (2023), https://doi.org/10.24435/materialscloud:kz-b7

Description

A theory for strengthening for multicomponent non-dilute alloys possessing short-range order (SRO) has recently been developed. The theory predicts that, in addition to a well-known athermal strengthening, there is a notable effect of SRO on the solute–dislocation interactions that can decrease or increase the strength relative to a random alloy. Here, carefully designed atomistic simulations in a model binary NbW alloy are used to demonstrate that alloy strength due to solute–dislocation interactions can be increased or decreased, depending on the SRO and consistent with theoretical predictions. Specifically, SRO is introduced using fictitious solute– solute interactions in an alloy system with very small true solute–solute interactions, and the Nudged Elastic Band (NEB) method is then used to compute the energy barriers for edge dislocation motion for various levels of SRO. Energy barriers, and hence alloy strengths, can be decreased when the Warren-Cowley SRO parameters are negative (attraction of unlike solutes). The theoretical predictions for the same system are in reasonable quantitative agreement with the simulation results. These findings demonstrate the unexpected possibility of reduced strength due to SRO and also further validate the analytical theory as a tool to guide alloy design.

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File name	Size	Description
files.zip MD5md5:fe285c2a081bb8eab6a0c340ac871127	237.1 MiB	Simulation codes and results

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Keywords

Alloys Yield strength Short-range order Theory Simulation MARVEL