Effect of Ti on phase stability and strengthening mechanisms of a nanocrystalline CoCrFeMnNi high-entropy alloy

Hamed Shahmir , Mahmoud Nili-Ahmadabadi , Ahad Shafiee , Mariusz Andrzejczuk , Małgorzata Lewandowska , Terence G. Langdon

Abstract

A CoCrFeNiMnTi0.1 high-entropy alloy (HEA) was processed by high-pressure torsion (HPT) followed by postdeformation annealing (PDA) at 200–900 °C. Microstructural evaluations revealed that the initial and HPTprocessed microstructures consisted of a single fcc phase and there was no evidence for decomposition during severe plastic deformation. However, PDA at temperatures below 900 °C promoted the formation of a multiphase microstructure containing new precipitates and significant grain coarsening occurred after PDA at> 800 °C due to a dissolution of the precipitates. PDA at 800 °C for 60 min led to very good mechanical properties with an ultimate tensile strength (UTS) and elongation to failure of> 1000 MPa and ~ 40%, respectively. The results demonstrate that the minor addition of Ti to the CoCrFeNiMn alloy has no direct effect on the strengthening mechanisms but nevertheless this addition significantly increases the thermal stability of the precipitates and these precipitates are effective in minimizing grain coarsening. Therefore, the Ti addition plays an important role in strengthening the HEA.
Author Hamed Shahmir
Hamed Shahmir,,
-
, Mahmoud Nili-Ahmadabadi
Mahmoud Nili-Ahmadabadi,,
-
, Ahad Shafiee
Ahad Shafiee,,
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, Mariusz Andrzejczuk (FMSE / DMD)
Mariusz Andrzejczuk,,
- Division of Materials Design
, Małgorzata Lewandowska (FMSE / DMD)
Małgorzata Lewandowska,,
- Division of Materials Design
, Terence G. Langdon
Terence G. Langdon,,
-
Journal seriesMaterials Science and Engineering A-Structural Materials Properties Microstructure And Processing, ISSN 0921-5093, (A 35 pkt)
Issue year2018
Vol725
Pages196-206
Publication size in sheets0.5
Keywords in EnglishCoCrFeNiMnTi, High-entropy alloy, High-pressure torsion, Post-deformation annealing, Severe plastic deformation
DOIDOI:10.1016/j.msea.2018.04.014
Languageen angielski
File
2018 MSEA Shahmir.pdf 6.7 MB
Score (nominal)35
ScoreMinisterial score = 35.0, 27-04-2018, ArticleFromJournal
Ministerial score (2013-2016) = 35.0, 27-04-2018, ArticleFromJournal
Publication indicators WoS Impact Factor: 2016 = 3.094 (2) - 2016=3.242 (5)
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