Effect of starting grain size on the evolution of microstructure and texture during thermo-mechanical processing of CoCrFeMnNi high entropy alloy

G D, Sathiaraj and Bhattacharjee, Pinaki Prasad (2015) Effect of starting grain size on the evolution of microstructure and texture during thermo-mechanical processing of CoCrFeMnNi high entropy alloy. Journal of Alloys and Compounds, 647. pp. 82-96. ISSN 0925-8388

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Abstract

The effect of starting grain size on the formation of microstructure and texture in heavily deformed equiatomic CoCrFeMnNi high entropy alloy (HEA) was investigated. For this purpose two alloys with average grain size ∼7 μm (fine grained starting material or FGSM) and 200 μm (coarse grained starting material or CGSM) were cold-rolled to 90% and 95% reduction in thickness and isochronally annealed for one hour at temperatures ranging from 700 °C to 1200 °C. Development of strong brass type texture, typical of low stacking fault energy (SFE) materials was noticed in both FGSM and CGSM. Near ultrafine microstructure formation was observed after annealing at 700 °C but extensive grain growth was observed only after annealing at 1200 °C. The FGSM showed finer grain size as compared to CGSM after heavy deformation and annealing. The annealing twin boundary fraction increased with increasing annealed grain size. The annealing textures of both FGSM and CGSM did not show strong dominance of the {236<385> or {113}<332> components unlike low SFE brass. Furthermore, the volume fractions of different annealing texture components of the HEA were not significantly affected by starting grain size or annealing temperature in stark contrast to low SFE brass. These differences could be explained on the basis of homogenously deformed matrix and sluggish diffusion in HEA which greatly reduced the preferential nucleation and growth of components, respectively.

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IITH Creators:

IITH Creators	ORCiD
Bhattacharjee, Pinaki Prasad	http://orcid.org/0000-0002-6422-2601

Item Type:

Article

Additional Information:

The authors also acknowledge Pro- fessor J.W. Yeh, National Tsing Hua University, Taiwan for kindly providing the starting HEA used in the present research work and Prof. I. Samajdar, IIT Mumbai, India for kindly providing access tothe national facility for Texture-OIM (DST-IRPHA) at I.I.T. Bombay, India.

Uncontrolled Keywords:

Metals and alloys; Microstructure; Texture; Grain boundaries; Scanning electron microscopy; X-ray diffraction

Subjects:

Others > Metallurgy
Materials Engineering > Materials engineering

Divisions:

Department of Material Science Engineering

Depositing User:

Team Library

Date Deposited:

30 Jul 2015 07:08

Last Modified:

31 Aug 2017 06:47