Tribological Properties of AlCrCuFeNi2 High-Entropy Alloy in Different Conditions

Liu, Yong; Ma, Shuang; Gao, Michael C.; Zhang, Chuan; Zhang, Teng; Yang, Huijun; Wang, Zhi Hua; Qiao, J.W.

doi:10.1007/s11661-016-3396-8

Cited by 97 publications

(19 citation statements)

References 33 publications

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“…In the case of multi-phase alloys, these are differentiated as FCC-or BCC-based, corresponding to the primary phase. In all but the present case, the data correspond to experiments performed in environments with sufficient oxygen concentration to drive the formation of mixed metal-oxide films [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] . A conclusion of this work is that, when sheared in UHV, the soft, single-phase (FCC), initially coarse grained (42 µm) CoCrFeMnNi specimens used in this investigation showed nearly the lowest wear rates.…”

Section: Sssupporting

confidence: 63%

Evidence of Inverse Hall-Petch Behavior and Low Friction and Wear in High Entropy Alloys

Jones

Nation

Wellington-Johnson

et al. 2020

Sci Rep

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We present evidence of inverse Hall-petch behavior for a single-phase high entropy alloy (cocrfeMnni) in ultra-high vacuum and show that it is associated with low friction coefficients (~0.3). Grain size measurements by STEM validate a recently proposed dynamic amorphization model that accurately predicts grain size-dependent shear strength in the inverse Hall-Petch regime. Wear rates in the initially soft (coarse grained) material were shown to be remarkably low (~10-6 mm 3 /n-m), the lowest for any HEA tested in an inert environment where oxidation and the formation of mixed metal-oxide films is mitigated. the combined high wear resistance and low friction are linked to the formation of an ultra-nanocrystalline near-surface layer. The dynamic amorphization model was also used to predict an average high angle grain boundary energy (0.87 J/m 2). this value was used to explain cavitationinduced nanoporosity found in the highly deformed surface layer, a phenomenon that has been linked to superplasticity. Since their discovery in 2004 1,2 , high entropy alloys (HEAs) have been extensively investigated and shown to exhibit remarkable thermomechanical properties 3,4. Studies of grain-size dependent mechanical behavior are limited 5,6 , however, especially in the regime of ultra-nanocrystalline grain size where softening (i.e. inverse Hall-Petch behavior) occurs. Recent work has also shown that these alloys are ideally suited for processing using laser-based additive manufacturing techniques 7-9 , as they exhibit high phase stability and derive much of their strength from thermal history-insensitive mechanisms like solution strengthening 10. While recent publications have presented experimental evidence of low friction or high wear resistance (but typically not both) with HEAs 11-25 , they were performed in environments where oxidation and the formation of mixed metal-oxide surface films was prevalent. These phenomena can greatly impact strength and deformation/wear resistance. We show that in an ultra-high vacuum (UHV) environment, i.e., in the absence of chemically reactive species, an additively manufactured initially coarse grained (soft), single-phase HEA exhibited a tendency toward low friction coefficients (i.e., low shear strength) and some of the lowest wear rates currently reported for these materials. The low friction and wear are attributed to a propensity for extreme grain refinement under sliding contact. Specifically, we present evidence of that this high strain rate shear leads to dynamic amorphization and inverse Hall-Petch behavior in the surface layer. In the present context of sliding contacts, dynamic amorphization refers to the continuous shear-induced generation of a structurally amorphous layer that accommodates deformation 26. This is in competition with stress-and temperature-driven grain growth and recrystallization, all of which reestablish crystallinity and order in the shear layer. The shear layer must be amorphized again in subsequent contact passes, thus we refer to this process as dynam...

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Section: Sssupporting

confidence: 63%

Evidence of Inverse Hall-Petch Behavior and Low Friction and Wear in High Entropy Alloys

Jones

Nation

Wellington-Johnson

et al. 2020

Sci Rep

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“…Similar behavior for a dry contact of CoCrFeMnNi in contact with a Si 3 N 4 sphere was reported in the literature [17], albeit for fretting conditions. An adhesive wear mechanism was also observed for other compositional complex alloys [38][39][40]. This being said and while there seems to be growing evidence for higher adhesive forces with HEAs, a statement about the universality of this behavior will require more and detailed studies.…”

Section: Discussion Friction and Wear Mechanismsmentioning

confidence: 77%

Microstructural changes in CoCrFeMnNi under mild tribological load

et al. 2020

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The lack of a principle element in high-entropy alloys (HEA) leads to unique and unexpected material properties. Tribological loading of metallic materials often results in deformed subsurface layers. As the microstructure feedbacks with friction forces, the microstructural evolution is highly dynamic and complex. The concept of HEAs promises high solid solution strengthening, which might decrease these microstructural changes. Here, we experimentally investigated the deformation behavior of CoCrFeMnNi in a dry, reciprocating tribological contact under a mild normal load. After only a single stroke, a surprisingly thick subsurface deformation layer was observed. This layer is characterized by nanocrystalline grains, twins and bands of localized dislocation motion. Twinning was found to be decisive for the overall thickness of this layer, and twin formation within the stress field of the moving sphere is analyzed. The localization of dislocation activity, caused by planar slip, results in a grain rotation. Fragmentation of twins and dislocation rearrangement lead to a nanocrystalline layer underneath the worn surface. In addition, oxide-rich layers were found after several sliding cycles. These oxides intermix with the nanocrystalline layer due to material transfer to the counter body and re-deposition to the wear track. Having revealed these fundamental mechanisms, the evolution of such deformation layers in CoCrFeMnNi under a tribological load might lead to other HEAs with compositions and properties specifically tailored to tribological applications in the future.

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“…During the running-in period, initially coarse surfaces are ground to smooth status owing to the higher friction force. 29) COF of M2052 substrate with an average value of 0.69 is higher than that of coated samples with an average value of 0.56. What's more, contrasted to that of uncoated samples, the curve of coated samples is extremely smooth with evidently slight fluctuation.…”

Section: Wear Behaviorsmentioning

confidence: 70%

Enhancement of Wear and Corrosion Resistance of M2052 Damping Alloys by Electroless Plating Ni–P Coating

et al. 2020

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M2052 is a famous high damping Mn-Cu alloys with good strength, but lack of well corrosion and wear resistance. In this study, we expect to enhance the wear and corrosion resistance of M2052 damping alloys by electroless plating NiP coating. Successfully, a high phosphorus amorphous NiP coating with thickness about 15 μm plated on M2052 substrate. After electroless plating NiP coating, the roughness of samples surface decreased and the microhardness increased. Thus, the coated sample featured better wear resistance, and attributed to adhesive wear mechanism. By contrast, the friction coefficients of uncoated samples presented a high value with great fluctuations, which due to low hardness, high roughness, and easier to be oxidized. This leads to the dominant wear mechanisms are abrasive and corrosive wears. NiP coating significantly improved the corrosion resistance, because it has lower I corr , higher E corr , and higher impedance than M2052 substrate. Surface morphologies after electrochemical tests were also observed: the uncoated samples had been corroded severely with a fibrous corrosion product layer dispersing cracks and pits. However, coated samples had not been corroded and remains intact. Furthermore, Mott-Schottky plots inferred that the sample surface after plating NiP coating performed an excellent passivation behavior in NaCl solution.

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Tribological Properties of AlCrCuFeNi2 High-Entropy Alloy in Different Conditions

Cited by 97 publications

References 33 publications

Evidence of Inverse Hall-Petch Behavior and Low Friction and Wear in High Entropy Alloys

Evidence of Inverse Hall-Petch Behavior and Low Friction and Wear in High Entropy Alloys

Microstructural changes in CoCrFeMnNi under mild tribological load

Enhancement of Wear and Corrosion Resistance of M2052 Damping Alloys by Electroless Plating Ni–P Coating

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