Novel casting CoCrNiAl eutectic high entropy alloys with high strength and good ductility

Abstract

Eutectic high-entropy alloys (EHEAs) have drawn increasing interest due to their fine castability as well as appealing properties in recent years. In this work, two bulk-casting Co_20-x/3Cr_20-x/3Ni_50-x/3Al_10+x (x = 8 and 9) EHEAs with regular L1₂/B2 lamellar morphologies were successfully fabricated and studied. Both EHEAs show high ultimate strength of ~1200 MPa combined with good uniform ductility (> 9%). Post-deformation transmission electron microscopy results indicated a high density of dislocations and stacking faults in the L1₂ lamellae, while no obvious dislocation in the B2 phases. This work can broaden the optimization of composition design in EHEAs and provide useful guidance for further development of CoCrNiAl EHEAs.

Keywords

Eutectic high-entropy alloys / lamellar morphology / stacking faults / dislocations

References

[1] Cantor B,Knight P.Microstructural development in equiatomic multicomponent alloys.Mater Sci Eng A2004;375-7:213-8

[2] Yeh JW,Lin SJ.Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes.Adv Eng Mater2004;6:299-303

[3] Zhang Y,Tang Z.Microstructures and properties of high-entropy alloys.Prog Mater Sci2014;61:1-93

[4] George EP,Ritchie RO.High-entropy alloys.Nat Rev Mater2019;4:515-34

[5] Lei Z,Wu Y.Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes.Nature2018;563:546-50

[6] Xu N,Li R.In situ investigation of the deformation behaviors of Fe₂₀Co₃₀Cr₂₅Ni₂₅ and Fe₂₀Co₃₀Cr₃₀Ni₂₀ high entropy alloys by high-energy X-ray diffraction.Mater Sci Eng A2020;795:139936

[7] Zhou S,Xue Y.Temperature-dependent mechanical behavior of an Al_0.5Cr_0.9FeNi_2.5V_0.2 high-entropy alloy.Appl Phys Lett2021;119:121902

[8] Lu W,Liebscher CH.Detwinning/twin growth-induced phase transformation in a metastable compositionally complex alloy.Microstructures2022;2:17

[9] Zhang T,Zhao D.Simultaneous enhancement of strength and ductility in a NiCoCrFe high-entropy alloy upon dynamic tension: Micromechanism and constitutive modeling.Int J Plast2020;124:226-46

[10] Ma Q,Wang Z,Liaw PK.High strength and ductility in partially recrystallized Fe₄₀Mn₂₀Cr₂₀Ni₂₀ high-entropy alloys at cryogenic temperature.Microstructures2022;2:15

[11] Yan X,Zhang Y.Ultrastrong and ductile BCC high-entropy alloys with low-density via dislocation regulation and nanoprecipitates.J Mater Sci Technol2022;110:109-16

[12] Lu Y,Guo S.A promising new class of high-temperature alloys: eutectic high-entropy alloys.Sci Rep2014;4:6200 PMCID:PMC4145285

[13] He J,Wang H.Effects of Al addition on structural evolution and tensile properties of the FeCoNiCrMn high-entropy alloy system.Acta Mater2014;62:105-13

[14] Gao X,Zhang B.Microstructural origins of high strength and high ductility in an AlCoCrFeNi_2.1 eutectic high-entropy alloy.Acta Mater2017;141:59-66

[15] Shi P,Zheng T.Enhanced strength-ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae.Nat Commun2019;10:489 PMCID:PMC6353877

[16] Lu Y,Jiang L.Directly cast bulk eutectic and near-eutectic high entropy alloys with balanced strength and ductility in a wide temperature range.Acta Mater2017;124:143-50

[17] Wani I,Sheikh S,Guo S.Tailoring nanostructures and mechanical properties of AlCoCrFeNi_2.1 eutectic high entropy alloy using thermo-mechanical processing.Mater Sci Eng A2016;675:99-109

[18] Wani IS,Sheikh S.Ultrafine-grained AlCoCrFeNi_2.1 eutectic high-entropy alloy.Mater Res Lett2016;4:174-9

[19] Shi P,Li Y.Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys.Science2021;373:912-8

[20] Jin X,Zhang L,Li B.A novel Fe₂₀Co₂₀Ni₄₁Al₁₉ eutectic high entropy alloy with excellent tensile properties.Mater Lett2018;216:144-6

[21] Huo W,Fang F,Jiang J.Microstructure and mechanical properties of CoCrFeNiZr_x eutectic high-entropy alloys.Mater Des2017;134:226-33

[22] Jin X,Zhang L.A new CrFeNi₂Al eutectic high entropy alloy system with excellent mechanical properties.J Alloys Compd2019;770:655-61

[23] Wang M,Wang T.A novel bulk eutectic high-entropy alloy with outstanding as-cast specific yield strengths at elevated temperatures.Scr Mater2021;204:114132

[24] Jiao W,Chang X.A novel Co-free Al_0.75CrFeNi eutectic high entropy alloy with superior mechanical properties.J Alloys Compd2022;902:163814

[25] Lu Y,Jiang H.Promising properties and future trend of eutectic high entropy alloys.Scr Mater2020;187:202-9

[26] He F,Cheng P.Designing eutectic high entropy alloys of CoCrFeNiNb_x.J Alloys Compd2016;656:284-9

[27] Liu F,Huang L,Liu Y.Design of NiCoCrAl eutectic high entropy alloys by combining machine learning with CALPHAD method.Mater Today Commun2022;30:103172

[28] Wu M,Huang H,Sun B.CALPHAD aided eutectic high-entropy alloy design.Mater Lett2020;262:127175

[29] Liu Q,Fan X.Designing novel AlCoCrNi eutectic high entropy alloys.J Alloys Compd2022;904:163775

[30] Duan D,Chen H.A strategy to design eutectic high-entropy alloys based on binary eutectics.J Mater Sci Technol2022;103:152-6

[31] Jiang H,Gao X.A new strategy to design eutectic high-entropy alloys using simple mixture method.Mater Des2018;142:101-5

[32] Yan P,Wang W,Lin M.Eutectic growth kinetics and microscopic mechanical properties of rapidly solidified CoCrFeNiMo_0.8 high entropy alloy.Acta Mater2022;237:118149

[33] Shi P,Wen Y.A precipitate-free AlCoFeNi eutectic high-entropy alloy with strong strain hardening.J Mater Sci Technol2021;89:88-96

[34] Dong Y,Huang X.Microstructure and mechanical properties of AlCo_xCrFeNi_3-x eutectic high-entropy-alloy system.J Alloys Compd2020;823:153886

[35] Shukla S,Cotton S.Hierarchical microstructure for improved fatigue properties in a eutectic high entropy alloy.Scr Mater2018;156:105-9

[36] Wu Q,Zheng T.A casting eutectic high entropy alloy with superior strength-ductility combination.Mate Lett2019;253:268-71

[37] Zhu Y.Perspective on hetero-deformation induced (HDI) hardening and back stress.Mater Res Lett2019;7:393-8

[38] Huang C,Ma X.Interface affected zone for optimal strength and ductility in heterogeneous laminate.Mater Today2018;21:713-9

[39] Rizi M, Minouei H, Lee BJ, Toroghinejad MR, Hong SI. Effects of carbon and molybdenum on the nanostructural evolution and strength/ductility trade-off in Fe₄₀Mn₄₀Co₁₀Cr₁₀ high-entropy alloys.J Alloys Compd2022;911:165108

[40] Ren J,Zhao D.Strong yet ductile nanolamellar high-entropy alloys by additive manufacturing.Nature2022;608:62-8