Short-range order localizing diffusion in multi-principal element alloys

The impact of chemical short-range order (SRO) on diffusion is computationally studied and theoretically analyzed in two classes of multi-principal elements alloys, fcc CrCoNi and bcc MoNbTa. We find the presence of SRO considerably reduces and localizes vacancy-mediated diffusion. The diffusivity r...

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Bibliographic Details
Published inScripta materialia Vol. 210; p. 114450
Main Authors Xing, Bin, Wang, Xinyi, Bowman, William J., Cao, Penghui
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 15.03.2022
Subjects
Diffusion correlation
Energy barrier
High-entropy alloy
Local chemical order
Short-range order
Diffusion correlation
Short-range order
Local chemical order
Energy barrier
High-entropy alloy
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Summary:The impact of chemical short-range order (SRO) on diffusion is computationally studied and theoretically analyzed in two classes of multi-principal elements alloys, fcc CrCoNi and bcc MoNbTa. We find the presence of SRO considerably reduces and localizes vacancy-mediated diffusion. The diffusivity reduction is induced by an increase of migration barrier (decreasing jump frequency) and enhanced diffusion correlation that lowers the effectiveness of atomic jumps. By sampling the diffusion pathways and associated energy barriers, a picture of SRO-stretched potential energy landscape is conceived that elucidates an increasing backward jumps and vacancy trapping effect stemming from chemical ordering. The results imply controlling the ordering in chemistry can act as a potential approach for manipulating diffusional behaviors in multi-principal elements alloys. [Display omitted]
ISSN:1359-6462
1872-8456
DOI:10.1016/j.scriptamat.2021.114450