Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Nov 23;7(1):16167.
doi: 10.1038/s41598-017-16509-9.

Enhanced strength and ductility in a friction stir processing engineered dual phase high entropy alloy

S S Nene  1 , K Liu  1 , M Frank  1 , R S Mishra  2 , R E Brennan  3 , K C Cho  3 , Z Li  4 , D Raabe  4
Affiliations

Enhanced strength and ductility in a friction stir processing engineered dual phase high entropy alloy

S S Nene et al. Sci Rep. .

Abstract

The potential of high-entropy alloys (HEAs) to exhibit an extraordinary combination of properties by shifting the compositional regime from the corners towards the centers of phase diagrams has led to worldwide attention by material scientists. Here we present a strong and ductile non-equiatomic HEA obtained after friction stir processing (FSP). A transformation-induced plasticity (TRIP) assisted HEA with composition Fe50Mn30Co10Cr10 (at.%) was severely deformed by FSP and evaluated for its microstructure-mechanical property relationship. The FSP-engineered microstructure of the TRIP HEA exhibited a substantially smaller grain size, and optimized fractions of face-centered cubic (f.c.c., γ) and hexagonal close-packed (h.c.p., ε) phases, as compared to the as-homogenized reference material. This results in synergistic strengthening via TRIP, grain boundary strengthening, and effective strain partitioning between the γ and ε phases during deformation, thus leading to enhanced strength and ductility of the TRIP-assisted dual-phase HEA engineered via FSP.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
(a–c) Phase maps for the material in the as-homogenized condition; after additional 350, and after 650 RPM processing, (d 1–d 2) corresponding EDS results for 350 RPM processed sample, (e) corresponding XRD results for the as-homogenized and FSP samples, (f) microstructural properties including the fraction of high angle grain boundaries, low angle grain boundaries, and kernel average misorientation values after FSP. AH: as-homogenized; FSP: friction stir processing; RPM: rotations per minute; LAGB: low angle grain boundary; HAGB: high angle grain boundary.
Figure 2
Figure 2
(a) True stress-true strain curves for the as-homogenized and FSP samples deformed at room temperature at an initial strain rate of 10−3 s−1, (b–d) EBSD maps showing f.c.c. γ- and h.c.p. ε-phase fractions prior to tensile deformation and, (e–h) EBSD maps and corresponding XRD patterns showing f.c.c. γ- and h.c.p. ε-phase fractions after tensile deformation. AH: as-homogenized; RPM: rotations per minute.
Figure 3
Figure 3
(a–c) EBSD image quality, phase, and KAM maps for the as-homogenized reference sample (d–f) image quality, phase, and KAM maps for the 350 RPM processed sample (g–i) image quality, phase, and KAM maps for the 650 RPM processed sample after room temperature tensile deformation at a strain rate of 10−3 s−1. RPM: rotations per minute; KAM: kernel average misorientation.
Figure 4
Figure 4
(a) Strength-ductility index (SDI) as a function of grain size and (b) variation of SDI as a function of ε phase fraction (prior to deformation) for grain-refined TRIP HEAs and non-TRIP HEAs. CG: coarse grained; FG: fine grained; FSP: friction stir processing; CR: cold rolling; RPM: rotations per minute.
See this image and copyright information in PMC

References

    1. Yeh J, et al. Nanostructured high entropy alloys with multiple component elements: novel alloy design concepts and outcomes. Adv. Eng. Mater. 2004;6:299–303. doi: 10.1002/adem.200300567. - DOI
    1. Cantor, B., Muticomponent and high entropy alloys, entropy 16, 4249–4268 (2014).
    1. Li Z, et al. Metastable high-entropy dual-phase alloys overcome the strength-ductility trade-off. Nature. 2016;534:227–30. doi: 10.1038/nature18453. - DOI - PubMed
    1. Li Z, et al. A TRIP-assisted dual-phase high-entropy alloy: grain size and phase fraction effects on deformation behavior. Acta Mater. 2017;131:323–335. doi: 10.1016/j.actamat.2017.03.069. - DOI
    1. Deng Y, et al. Design of a twinning-induced plasticity high entropy alloy. Acta. Mater. 2015;94:124–133. doi: 10.1016/j.actamat.2015.04.014. - DOI

Publication types

LinkOut - more resources