Strengthening and Toughening Mechanisms of Precipitation- Hardened Fe53Mn15Ni15Cr10Al4Ti2C1 High-Entropy Alloy
SUN Shijie1, TIAN Yanzhong2, ZHANG Zhefeng1()
1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China 2. School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China
Cite this article:
SUN Shijie, TIAN Yanzhong, ZHANG Zhefeng. Strengthening and Toughening Mechanisms of Precipitation- Hardened Fe53Mn15Ni15Cr10Al4Ti2C1 High-Entropy Alloy. Acta Metall Sin, 2022, 58(1): 54-66.
There has been significant progress in the development of high-entropy alloys (HEAs) with unconventional compositions in the past decade to meet the demand from a wide variety of industries, such as automotive, shipbuilding, and aerospace. The fcc HEAs have attracted growing attention due to their superior mechanical and functional properties. However, these HEAs exhibit low or modest yield strength, limiting their potential industrial application. To enhance the strength of the fcc HEAs, materials researchers are exploring additional strengthening methods, such as grain refinement, solid solution strengthening, and precipitation strengthening. However, the strengthening approaches mentioned above suffer from the trade-off dilemma between strength and ductility. In this study, a new precipitation-hardened Fe53Mn15Ni15Cr10Al4Ti2C1 HEA was designed by adding Al, Ti, and C elements based on the fcc HEA. Then the HEA was treated utilizing heavy-deformation and various heat-treatment processes, tuning the microstructure and precipitate. The cold-rolled alloy microstructure presented rolling bands (including deformation twins) and a significant dislocation density. Furthermore, the HEA microstructure consists of rolling bands, high-density dislocations, and nanoscale precipitates following heat treatment at medium temperatures for an extended period. In particular, the HEA possessed a superior balance between strength and ductility, resulting from the significant precipitation strengthening effect of L12 precipitates that were coherent with the matrix in the microstructure as well as the improved strain-hardening ability due to the recovery of dislocations. The precipitation-hardened HEA with an inhomogeneous microstructure could be obtained through heat treatment at medium temperatures over long periods, which exhibited an excellent strength-ductility relationship.
Fund: Fundamental Research Funds for the Central Universities(N180204015);Liaoning Revitalization Talents Program(XLYC1808027);Special Research Assistant Program of Chinese Academy of Sciences, and IMR Innovation Fund(2021-PY16)
About author: ZHANG Zhefeng, professor, Tel: (024)23971043, E-mail: zhfzhang@imr.ac.cn
Fig.1 XRD spectrum (a) and SEM image (b) of as-cast Fe53Mn15Ni15Cr10Al4Ti2C1 high-entropy alloy (HEA)
Fig.2 Microhardnesses of the cold-rolling (CR) Fe53Mn15Ni15Cr10Al4Ti2C1 sheets at different heat treatment processes(a) annealing at different temperatures for 1 h(b) annealing at 873 and 923 K for different time
Fig.3 XRD spectra of the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA with different heat treatment states and CR state
Fig.4 EBSD images of the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA with different heat treatment states (RD—rolling direction, ND—normal direction) (a) 873 K, 1 h (b) 873 K, 50 h (c) 923 K, 1 h (d) 1023 K, 1 h
Fig.5 BSE image of the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA annealing at 873 K for 50 h and SEM-EDS maps of Al, Ni, Fe, Ti, Cr,and Mn elements
Fig.6 TEM images of the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA with different states (a, b) CR state (c) 873 K, 1 h (d) 873 K, 50 h (e) 923 K, 1 h (f) 1023 K, 1 h
Fig.7 STEM high-angle annular dark field (HAADF ) images and corresponding STEM-EDS maps of square areas for each component in the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA with different states and CR state
Fig.8 TEM analyses of the Fe53Mn15Ni15Cr10Al4Ti2C1 HEA annealing at 873 K for 50 h (a) bright field TEM image showing the deformation twin and short-rod precipitate; inset showing the corresponding SAED pattern along z = [110] zone-axis (Arrow in the inset indicates the diffraction spot of Ll2 precipitate) (b) bright field TEM image showing the spherical precipitate (c) dark field TEM image showing the spherical precipitate (d) HRTEM image showing the precipitate and matrix, with their fast Fourier transform (FFT) patterns on the right-hand side
Fig.9 Tensile engineering stress-strain curves (a) and strain-hardening rate curves (b) of Fe53Mn15Ni15-Cr10Al4Ti2C1 HEAs in as-cast state, CR state, and in different heat treatment states, and plots of yield strength and uniform elongation for Fe53Mn15Ni15Cr10Al4Ti2C1 HEAs in this work and of other HEAs and medium-entropy alloys[6,7,12,13,21,30-44] as reported in the previous work (c)
Fig.10 TEM images of fractured Fe53Mn15Ni15Cr10Al4Ti2C1 HEA annealing at 873 K for 50 h
1
Yeh J W , Chen S K , Lin S J , et al . Nanostructured high-entropy alloys with multiple principal elements: Novel alloy design concepts and outcomes [J]. Adv. Eng. Mater., 2004, 6: 299
2
Zhang Y , Zuo T T , Tang Z , et al . Microstructures and properties of high-entropy alloys [J]. Prog. Mater. Sci., 2014, 61: 1
3
Sun S J , Tian Y Z , An X H , et al . Ultrahigh cryogenic strength and exceptional ductility in ultrafine-grained CoCrFeMnNi high-entropy alloy with fully recrystallized structure [J]. Mater. Today Nano, 2018, 4: 46
4
Schuh B , Mendez-Martin F , Völker B , et al . Mechanical properties, microstructure and thermal stability of a nanocrystalline CoCrFeMnNi high-entropy alloy after severe plastic deformation [J]. Acta Mater., 2015, 96: 258
5
Sun S J , Tian Y Z , Lin H R , et al . Enhanced strength and ductility of bulk CoCrFeMnNi high entropy alloy having fully recrystallized ultrafine-grained structure [J]. Mater. Des., 2017, 133: 122
6
He F , Chen D , Han B , et al . Design of D022 superlattice with superior strengthening effect in high entropy alloys [J]. Acta Mater., 2019, 167: 275
7
Qin G , Chen R R , Liaw P K , et al . A novel face-centered-cubic high-entropy alloy strengthened by nanoscale precipitates [J]. Scr. Mater., 2019, 172: 51
8
Wang Z W , Baker I , Cai Z H , et al . The effect of interstitial carbon on the mechanical properties and dislocation substructure evolution in Fe40.4Ni11.3Mn34.8Al7.5Cr6 high entropy alloys [J]. Acta Mater., 2016, 120: 228
9
Sun S J , Tian Y Z , Lin H R , et al . Revisiting the role of prestrain history in the mechanical properties of ultrafine-grained CoCrFe-MnNi high-entropy alloy [J]. Mater. Sci. Eng., 2021, A801: 140398
10
Wu Z G , Guo W , Jin K , et al . Enhanced strength and ductility of a tungsten-doped CoCrNi medium-entropy alloy [J]. J. Mater. Res., 2018, 33: 3301
11
Li Z M . Interstitial equiatomic CoCrFeMnNi high-entropy alloys: Carbon content, microstructure, and compositional homogeneity effects on deformation behavior [J]. Acta Mater., 2019, 164: 400
12
He J Y , Wang H , Huang H L , et al . A precipitation-hardened high-entropy alloy with outstanding tensile properties [J]. Acta Mater., 2016, 102: 187
13
Tong Y , Chen D , Han B , et al . Outstanding tensile properties of a precipitation-strengthened FeCoNiCrTi0.2 high-entropy alloy at room and cryogenic temperatures [J]. Acta Mater., 2019, 165: 228
14
Yang T , Zhao Y L , Tong Y , et al . Multicomponent intermetallic nanoparticles and superb mechanical behaviors of complex alloys [J]. Science, 2018, 362: 933
15
Choudhuri D , Alam T , Borkar T , et al . Formation of a Huesler-like L21 phase in a CoCrCuFeNiAlTi high-entropy alloy [J]. Scr. Mater., 2015, 100: 36
16
Shi P J , Li Y , Wen Y B , et al . A precipitate-free AlCoFeNi eutectic high-entropy alloy with strong strain hardening [J]. J. Mater. Sci. Technol., 2021, 89: 88
17
Ritchie R O . The conflicts between strength and toughness [J]. Nat. Mater., 2011, 10: 817
18
Zhu Y T , Wu X L . Perspective on hetero-deformation induced (HDI) hardening and back stress [J]. Mater. Res. Lett., 2019, 7: 393
19
Huang C X , Wang Y F , Ma X L , et al . Interface affected zone for optimal strength and ductility in heterogeneous laminate [J]. Mater. Today, 2018, 21: 713
20
Wang H W , He Z F , Jia N . Microstructure and mechanical properties of a FeMnCoCr high-entropy alloy with heterogeneous structure [J]. Acta Metall. Sin., 2021, 57: 632
Sun S J , Tian Y Z , Lin H R , et al . Achieving high ductility in the 1.7 GPa grade CoCrFeMnNi high-entropy alloy at 77 K [J]. Mater. Sci. Eng, 2019, A740-741: 336
22
Sun S J , Tian Y Z , Lin H R , et al . Modulating the prestrain history to optimize strength and ductility in CoCrFeMnNi high-entropy alloy [J]. Scr. Mater., 2019, 163: 111
23
Fu Z Q , Macdonald B E , Li Z M , et al . Engineering heterostructured grains to enhance strength in a single-phase high-entropy alloy with maintained ductility [J]. Mater. Res. Lett., 2018, 6: 634
24
Slone C E , Miao J , George E P , et al . Achieving ultra-high strength and ductility in equiatomic CrCoNi with partially recrystallized microstructures [J]. Acta Mater., 2019, 165: 496
25
Chang R B , Fang W , Yu H Y , et al . Heterogeneous banded precipitation of (CoCrNi)93Mo7 medium entropy alloys towards strength-ductility synergy utilizing compositional inhomogeneity [J]. Scr. Mater., 2019, 172: 144
26
Donadille C , Valle R , Dervin P , et al . Development of texture and microstructure during cold-rolling and annealing of F.C.C. alloys: Example of an austenitic stainless steel [J]. Acta Metall., 1989, 37: 1547
27
Di Schino A , Kenny J M , Abbruzzese G . Analysis of the recrystallization and grain growth processes in AISI 316 stainless steel [J]. J. Mater. Sci., 2002, 37: 5291
28
Zhao Y L , Yang T , Tong Y , et al . Heterogeneous precipitation behavior and stacking-fault-mediated deformation in a CoCrNi-based medium-entropy alloy [J]. Acta Mater., 2017, 138: 72
29
Joshi C , Abinandanan T A , Choudhury A . Phase field modelling of rayleigh instabilities in the solid-state [J]. Acta Mater., 2016, 109: 286
30
Otto F , Dlouhý A , Somsen C , et al . The influences of temperature and microstructure on the tensile properties of a CoCrFeMnNi high-entropy alloy [J]. Acta Mater., 2013, 61: 5743
31
Sun S J , Tian Y Z , Lin H R , et al . Temperature dependence of the Hall-Petch relationship in CoCrFeMnNi high-entropy alloy [J]. J. Alloys Compd., 2019, 806: 992
32
Gludovatz B , Hohenwarter A , Catoor D , et al . A fracture-resistant high-entropy alloy for cryogenic applications [J]. Science, 2014, 345: 1153
33
Wu Z G , Parish C M , Bei H B . Nano-twin mediated plasticity in carbon-containing FeNiCoCrMn high entropy alloys [J]. J. Alloys Compd., 2015, 647: 815
34
Laplanche G , Kostka A , Reinhart C , et al . Reasons for the superior mechanical properties of medium-entropy CrCoNi compared to high-entropy CrMnFeCoNi [J]. Acta Mater., 2017, 128: 292
35
Miao J S , Slone C E , Smith T M , et al . The evolution of the deformation substructure in a Ni-Co-Cr equiatomic solid solution alloy [J]. Acta Mater., 2017, 132: 35
36
Wu Z G , Bei H B , Pharr G M , et al . Temperature dependence of the mechanical properties of equiatomic solid solution alloys with face-centered cubic crystal structures [J]. Acta Mater., 2014, 81: 428
37
Li D Y , Li C X , Feng T , et al . High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures [J]. Acta Mater., 2017, 123: 285
38
Li D Y , Zhang Y . The ultrahigh charpy impact toughness of forged AlxCoCrFeNi high entropy alloys at room and cryogenic temperatures [J]. Intermetallics, 2016, 70: 24
39
Jo Y H , Jung S , Choi W M , et al . Cryogenic strength improvement by utilizing room-temperature deformation twinning in a partially recrystallized VCrMnFeCoNi high-entropy alloy [J]. Nat. Commun., 2017, 8: 15719
40
Wu Z G , Bei H B . Microstructures and mechanical properties of compositionally complex Co-free FeNiMnCr18 FCC solid solution alloy [J]. Mater. Sci. Eng., 2015, A640: 217
41
Chen L B , Wei R , Tang K , et al . Ductile-brittle transition of carbon alloyed Fe40Mn40Co10Cr10 high entropy alloys [J]. Mater. Lett., 2019, 236: 416
42
Bhattacharjee T , Zheng R X , Chong Y , et al . Effect of low temperature on tensile properties of AlCoCrFeNi2.1 eutectic high entropy alloy [J]. Mater. Chem. Phys., 2018, 210: 207
43
Liu W H , Lu Z P , He J Y , et al . Ductile CoCrFeNiMox high entropy alloys strengthened by hard intermetallic phases [J]. Acta Mater., 2016, 116: 332
44
Ming K S , Bi X F , Wang J . Realizing strength-ductility combination of coarse-grained Al0.2Co1.5CrFeNi1.5Ti0.3 alloy via nano-sized, coherent precipitates [J]. Int. J. Plast., 2018, 100: 177
45
Odnobokova M , Belyakov A , Kaibyshev R . Effect of severe cold or warm deformation on microstructure evolution and tensile behavior of a 316L stainless steel [J]. Adv. Eng. Mater., 2015, 17: 1812
46
Li J S , Cao Y , Gao B , et al . Superior strength and ductility of 316L stainless steel with heterogeneous lamella structure [J]. J. Mater. Sci., 2018, 53: 10442
47
Cheng Q , Xu X D , Xie P , et al . Unveiling anneal hardening in dilute Al-doped AlxCoCrFeMnNi (x = 0, 0.1) high-entropy alloys [J]. J. Mater. Sci. Technol., 2021, 91: 270
48
Gu J , Song M . Annealing-induced abnormal hardening in a cold rolled CrMnFeCoNi high entropy alloy [J]. Scr. Mater., 2019, 162: 345
49
Pickering E J , Muñoz-Moreno R , Stone H J , et al . Precipitation in the equiatomic high-entropy alloy CrMnFeCoNi [J]. Scr. Mater., 2016, 113: 106
50
Nembach E V . Particle Strengthening of Metals and Alloys [M]. New York: John Wiley, 1997: 1
51
Vo N Q , Liebscher C H , Rawlings M J S , et al . Creep properties and microstructure of a precipitation-strengthened ferritic Fe-Al-Ni-Cr alloy [J]. Acta Mater., 2014, 71: 89
52
Shao C W , Zhang P , Zhu Y K , et al . Simultaneous improvement of strength and plasticity: Additional work-hardening from gradient microstructure [J]. Acta Mater., 2018, 145: 413
53
Gil Sevillano J , de las Cuevas F . Internal stresses and the mechanism of work hardening in twinning-induced plasticity steels [J]. Scr. Mater., 2012, 66: 978
54
Gutierrez-Urrutia I , Raabe D . Dislocation and twin substructure evolution during strain hardening of an Fe-22 wt.%Mn-0.6 wt.%C TWIP steel observed by electron channeling contrast imaging [J]. Acta Mater., 2011, 59: 6449
55
Gutierrez-Urrutia I , Raabe D . Multistage strain hardening through dislocation substructure and twinning in a high strength and ductile weight-reduced Fe-Mn-Al-C steel [J]. Acta Mater., 2012, 60: 5791