Microstructures and properties of high-entropy alloys

Microstructures and properties of high-entropy

alloys

Yong Zhang a ,?,Ting Ting Zuo a ,Zhi Tang b ,Michael C.Gao c ,d ,Karin A.Dahmen e ,Peter K.Liaw b ,Zhao Ping Lu a

a State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China

b Department of Materials Science and Engineering,The University of Tennessee,Knoxville,TN 37996,USA

c National Energy Technology Laboratory,1450Queen Ave SW,Albany,OR 97321,USA

d URS Corporation,PO Box 1959,Albany,OR 97321-2198,USA

e Department o

f Physics,University of Illinois at Urbana-Champaign,1110West Green Street,Urbana,IL 61801-3080,USA a r t i c l e i n f o Article history:Received 26September 2013Accepted 8October 2013Available online 1November 2013

a b s t r a c t

This paper reviews the recent research and development of high-

entropy alloys (HEAs).HEAs are loosely de?ned as solid solution

alloys that contain more than ?ve principal elements in equal or

near equal atomic percent (at.%).The concept of high entropy

introduces a new path of developing advanced materials with

unique properties,which cannot be achieved by the conventional

micro-alloying approach based on only one dominant element.

Up to date,many HEAs with promising properties have been

reported, e.g.,high wear-resistant HEAs,Co 1.5CrFeNi 1.5Ti and

Al 0.2Co 1.5CrFeNi 1.5Ti alloys;high-strength body-centered-cubic

(BCC)AlCoCrFeNi HEAs at room temperature,and NbMoTaV HEA

at elevated temperatures.Furthermore,the general corrosion resis-

tance of the Cu 0.5NiAlCoCrFeSi HEA is much better than that of the

conventional 304-stainless steel.This paper ?rst reviews HEA for-

mation in relation to thermodynamics,kinetics,and processing.

Physical,magnetic,chemical,and mechanical properties are then

discussed.Great details are provided on the plastic deformation,

fracture,and magnetization from the perspectives of crackling

noise and Barkhausen noise measurements,and the analysis of ser-

rations on stress–strain curves at speci?c strain rates or testing

temperatures,as well as the serrations of the magnetization

hysteresis loops.The comparison between conventional and

high-entropy bulk metallic glasses is analyzed from the viewpoints

of eutectic composition,dense atomic packing,and entropy of 0079-6425/$-see front matter ó2013Elsevier Ltd.All rights reserved.f9ab872d551810a6f4248668/10.1016/j.pmatsci.2013.10.001?Corresponding author.Tel.:+8601062333073;fax:+8601062333447.

E-mail address:drzhangy@f9ab872d551810a6f4248668 (Y.Zhang).

2Y.Zhang et al./Progress in Materials Science61(2014)1–93

mixing.Glass forming ability and plastic properties of high-

entropy bulk metallic glasses are also discussed.Modeling tech-

niques applicable to HEAs are introduced and discussed,such as

ab initio molecular dynamics simulations and CALPHAD modeling.

Finally,future developments and potential new research directions

for HEAs are proposed.

ó2013Elsevier Ltd.All rights reserved. Contents

1.Introduction (3)

1.1.Four core effects (4)

1.1.1.High-entropy effect (4)

1.1.2.Sluggish diffusion effect (5)

1.1.3.Severe lattice-distortion effect (6)

1.1.4.Cocktail effect (7)

1.2.Key research topics (9)

1.2.1.Mechanical properties compared with other alloys (10)

1.2.2.Underlying mechanisms for mechanical properties (11)

1.2.3.Alloy design and preparation for HEAs (11)

1.2.4.Theoretical simulations for HEAs (12)

2.Thermodynamics (12)

2.1.Entropy (13)

2.2.Thermodynamic considerations of phase formation (15)

2.3.Microstructures of HEAs (18)

3.Kinetics and alloy preparation (23)

3.1.Preparation from the liquid state (24)

3.2.Preparation from the solid state (29)

3.3.Preparation from the gas state (30)

3.4.Electrochemical preparation (34)

4.Properties (34)

4.1.Mechanical behavior (34)

4.1.1.Mechanical behavior at room temperature (35)

4.1.2.Mechanical behavior at elevated temperatures (38)

4.1.3.Mechanical behavior at cryogenic temperatures (45)

4.1.4.Fatigue behavior (46)

4.1.5.Wear behavior (48)

4.1.6.Summary (49)

4.2.Physical behavior (50)

4.3.Biomedical,chemical and other behaviors (53)

5.Serrations and deformation mechanisms (55)

5.1.Serrations for HEAs (56)

5.2.Barkhausen noise for HEAs (58)

5.3.Modeling the Serrations of HEAs (61)

5.4.Deformation mechanisms for HEAs (66)

6.Glass formation in high-entropy alloys (67)

6.1.High-entropy effects on glass formation (67)

6.1.1.The best glass former is located at the eutectic compositions (67)

6.1.2.The best glass former is the composition with dense atomic packing (67)

6.1.3.The best glass former has high entropy of mixing (67)

6.2.GFA for HEAs (68)

6.3.Properties of high-entropy BMGs (70)

7.Modeling and simulations (72)

7.1.DFT calculations (73)

7.2.AIMD simulations (75)

7.3.CALPHAD modeling (80)

8.Future development and research (81)

Y.Zhang et al./Progress in Materials Science61(2014)1–933

8.1.Fundamental understanding of HEAs (82)

8.2.Processing and characterization of HEAs (83)

8.3.Applications of HEAs (83)

9.Summary (84)

Disclaimer (85)

Acknowledgements (85)

References (85)

1.Introduction

Recently,high-entropy alloys(HEAs)have attracted increasing attentions because of their unique compositions,microstructures,and adjustable properties[1–31].They are loosely de?ned as solid solution alloys that contain more than?ve principal ele …… 此处隐藏：39382字，全部文档内容请下载后查看。喜欢就下载吧 ……