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. 2018 Apr 25;11(5):669.
doi: 10.3390/ma11050669.

Enhanced Strength of a Mechanical Alloyed NbMoTaWVTi Refractory High Entropy Alloy

Yan Long  1 , Kai Su  2 , Jinfu Zhang  3 , Xiaobiao Liang  4 , Haiyan Peng  5 , Xiaozhen Li  6
Affiliations

Enhanced Strength of a Mechanical Alloyed NbMoTaWVTi Refractory High Entropy Alloy

Yan Long et al. Materials (Basel). .

Abstract

A NbMoTaWVTi refractory high entropy alloy (HEA) has been successfully synthesized by mechanical alloying (MA) and spark plasma sintering (SPS). The microstructure and mechanical properties of this alloy are investigated. It is observed that only two types of body-centered cubic (BCC) solid solutions are formed in the powders after ball milling for 40 h. However, a new face-centered cubic (FCC) precipitated phase is observed in the BCC matrix of bulk material consolidated by SPS. The FCC precipitated phase is identified as TiO, due to the introduction of O during the preparing process of HEA. The compressive yield strength, fracture strength, and total fracture strain of the consolidated bulk HEA are 2709 MPa, 3115 MPa, and 11.4%, respectively. The excellent mechanical properties can be attributed to solid solution strengthening and grain boundary strengthening of the fine-grained BCC matrix, as well as the precipitation strengthening owing to the formation of TiO particles.

Keywords: mechanical properties; microstructure; refractory high entropy alloy.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(a) XRD patterns of NbMoTaWVTi powders with different milling times; (b) SEM image and corresponding SAED pattern of the high entropy alloy (HEA) powders after 40 h of milling; (c) XRD patterns of ball milled powders heat-treated at 500 °C, 900 °C for 1 h, and bulk HEA after spark plasma sintering (SPS) at 1400 °C; (d) DSC curve of the HEA powders after 40 h of milling.
Figure 2
Figure 2
(a) SEM back scatter electron images of the bulk NbMoTaWVTi HEA at different magnifications and (b) Elemental composition gradients along the red drawn line.
Figure 3
Figure 3
TEM images of the bulk NbMoTaWVTi HEA: (a) Bright-field image; (b,c) SAED patterns of BCC1 phase along [111] and [001] zone axis, respectively; (d–f) SAED patterns of FCC phase along [011], [001] and [112] zone axis, respectively.
Figure 4
Figure 4
(a) Compressive engineering stress–strain curve of the bulk NbMoTaWVTi HEA; (b) Compressive yield strength versus fracture strain of the bulk HEA in the present work and available data in the literature; (c) Fracture morphologies of bulk HEA at low magnification; (d) High-magnified image of intergranular fracture area.
See this image and copyright information in PMC

References

    1. Yeh J.W., Chen S.K., Lin S.J. Nanostructured High-Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes. Adv. Eng. Mater. 2004;6:299–303. doi: 10.1002/adem.200300567. - DOI
    1. Zhang Y., Zou T.T., Tang Z., Gao M.C., Dahmen K.A., Liaw P.K., Lu Z.P. Microstructures and properties of high-entropy alloys. Prog. Mater. Sci. 2014;61:1–93. doi: 10.1016/j.pmatsci.2013.10.001. - DOI
    1. Zhang K.B., Fu Z.Y., Zhang J.Y. Annealing on the structure and properties evolution of the CoCrFeNiCuAl high-entropy alloy. J. Alloys Compd. 2010;502:295–299. doi: 10.1016/j.jallcom.2009.11.104. - DOI
    1. Sriharitha B., Murty B.S., Kottada R.S. Alloying, thermal stability and strengthening in spark plasma sintered AlxCoCrCuFeNi high entropy alloys. J. Alloys Compd. 2014;583:419–426. doi: 10.1016/j.jallcom.2013.08.176. - DOI
    1. Senkov O.N., Wilks G.B., Scott J.M., Miracle D.B. Mechanical properties of Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 refractory high entropy alloys. Intermetallics. 2011;19:698–706. doi: 10.1016/j.intermet.2011.01.004. - DOI

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