Title: Microstructure and Mechanical Behavior of High-Entropy Alloys

Abstract

High entropy alloys (HEA) have generated interest in recent years due to their unique positioning within the alloy world. By incorporating a number of elements in high proportion, usually of equal atomic percent, they have high configurational entropy, and thus, they hold the promise of interesting and useful properties such as enhanced strength and alloy stability. The present study investigates the mechanical behavior, fracture characteristics and microstructure of two singlephase FCC high-entropy alloys (HEA's) CoCrFeNi and CoCrFeNiMn with some detailed attention given to melting, homogenization and thermo-mechanical processing. Ingots approaching 8 kg in mass were made by vacuum induction melting (VIM) to avoid the extrinsic factors inherent to small scale laboratory button samples. A computationally based homogenization heat treatment was given to both alloys in order to eliminate any solidification segregation. The alloys were then fabricated in the usual way (forging, followed by hot rolling) with typical thermo-mechanical processing parameters employed. Transmission electron microscopy (TEM) was subsequently used to assess the single phase nature of the alloys prior to mechanical testing. Tensile specimens (ASTM E8) were prepared with tensile mechanical properties obtained from room temperature through 800°C. Material from the gage section of selected tensile specimens was extracted to documentmore » room and elevated temperature deformation within the HEA's. Fracture surfaces were also examined to note fracture failure modes. The tensile behavior and selected tensile properties were compared with results in the literature for similar alloys.« less

Authors:

Licavoli, Joseph J. ^[1]; Gao, Michael C. ^[2]; Sears, John S. ^[2]; Jablonski, Paul D. ^[1]; Hawk, Jeffrey A. ^[1]

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+ Show Author Affiliations

1. National Energy Technology Lab. (NETL), Albany, OR (United States)
2. National Energy Technology Lab. (NETL), Albany, OR (United States); AECOM, Albany, OR (United States)

Publication Date:

Thu Aug 27 00:00:00 EDT 2015

Research Org.:

National Energy Technology Lab. (NETL), Albany, OR (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1482330

Grant/Contract Number:  

FE0004000

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Materials Engineering and Performance

Additional Journal Information:

Journal Volume: 24; Journal Issue: 10; Journal ID: ISSN 1059-9495

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE