Friction stress and Hall-Petch relationship in CoCrNi equi-atomic medium entropy alloy processed by severe plastic deformation and subsequent annealing

• Published in: Scripta materialia Vol. 134; pp. 33 - 36
• Main Authors: Yoshida, Shuhei, Bhattacharjee, Tilak, Bai, Yu, Tsuji, Nobuhiro
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2017
• Subjects: Grain refining; Hall-Petch effect; Local lattice distortion; Severe plastic deformation (SPD); Local lattice distortion; Hall-Petch effect; Grain refining; Severe plastic deformation (SPD)
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2017.02.042

The present work focuses on the friction stress and the Hall-Petch relationship in CoCrNi equi-atomic medium entropy alloy (MEA). The CoCrNi equi-atomic MEA and a Ni-40Co alloy were processed by high-pressure torsion and subsequent annealing. The specimens with fully-recrystallized microstructure with different grain sizes ranging from 199nm to 111μm were obtained. The Hall-Petch plot of the yield strength of the present specimens indicated that the friction stress of the CoCrNi MEA was much higher than Ni-40Co and pure metals, suggesting that the local lattice distortion in the equi-atomic alloy played an important role for the dislocation activity.
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