Point defects in FeAl Σ(-1-20) grain boundary : a first principles study
1University of Oulu, Faculty of Science, Physics
|Online Access:||PDF Full Text (PDF, 9.8 MB)|
|Persistent link:|| http://urn.fi/URN:NBN:fi:oulu-202005262190
Oulu : T. Lehenkari,
|Publish Date:|| 2020-05-26
|Thesis type:||Bachelor's thesis
Density functional theory has revolutionized computational material physics and its usage in research has increased annually to this day.
This thesis is a first principles computational study on the hydrogen embrittlement of FeAl. Point defects of hydrogen and vacancies were introduced to the Σ5(-1-20) grain boundary. The probability of the defect formation was considered by calculating formation energies and the strength of the structure by cohesive energies.
Correlation was found between the stability of the structure and the hydrogen defects density of states. All the point defects were probable to form in the grain boundary and increased the structures stability. Therefore the hydrogen embrittlement observed on the macro scale was not present in the case of the point defects used in this study. The structural failure can still be due to larger complexes of defects.
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