Abstract High-entropy alloys (HEAs) with a single-phase face-centered cubic (FCC) structure generally have excellent plasticity. However, its limited room temperature strength and hardness result in lower wear resistance, which hinders tribological and engineering applications. In this paper, the pack-boronizing method was used to improve the tribological properties of Al0·1CoCrFeNi HEAs with a single-phase FCC structure. The boronizing treatment was carried out at 900 °C for 2, 4, 6, and 8 h, respectively. The structure and phase formation of boronized alloys were studied. Moreover, the reciprocating sliding wear behavior of boronized alloys against Si3N4 balls in dry and deionized water was investigated. A boronized layer with a double-layer structure was formed on the HEA surface, with a total thickness of about 17.3–58.5 μm. The wear mechanism of boronized alloy was transformed from the abrasive and delamination wear to the polishing effect with increasing the boronizing time in air. In contrast, the wear mechanism of boronized alloys in the deionized water gradually changed from the two-body to three-body wear with increasing the boronizing time. Meanwhile, the wear mechanism of the Si3N4 counterface was also transformed to three-body wear gradually.
Last. Junwei Qiao(TUT: Taiyuan University of Technology)H-Index: 29
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Abstract Plasma nitriding is successfully employed in treating AlxCoCrFeNi high-entropy alloys (HEAs) with finely-divided Al content (i.e., x values in molar ratio, x = 0.1- 0.8) to develop wear-resistant structural materials. Nitridation greatly removes the Al from the matrix that completely deplete the Ni-Al enriched phase, forming nanoscaled nitrides (AlN and CrN) precipitations near the surface. Nitriding promotes the hardness of present alloys with values widely ranging from 276 HV to 722 H...
The surface hardening of single-face-centred cubic (fcc)-phase CrMnFeCoNi and the manganese-free CrFeCoNi alloy was conducted using low-temperature nitrocarburisation. The microstructural investigations reveal the successful formation of a homogeneous diffusion layer with a thickness of approximately 16 µm. The interstitial solution of carbon and nitrogen causes an anisotropic lattice expansion. The increase in microhardness is in accordance to the graded concentration profile of the interstitia...
#1Thomas Lindner(Chemnitz University of Technology)H-Index: 16
#1Thomas Lindner(Chemnitz University of Technology)H-Index: 8
Last. Thomas Lampke(Chemnitz University of Technology)H-Index: 23
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Abstract Face centred cubic (fcc) phase high-entropy alloys (HEA) exhibit a higher ductility compared to body centred cubic (bcc) phase or multiphase HEA systems. However, low hardness and low wear resistance prevent tribological applications. A precipitation hardening of the fcc phase CoCrFeMnNi and the manganese-free CoCrFeNi alloy was performed by powder-pack boriding. The microstructure, the phase formation and the wear resistance were investigated. The successful diffusion of elements is pr...
Abstract The wear behaviour of as-cast Al1.0CoCrFeNi with a body-centred cubic (BCC) structure and Al0.3CoCrFeNi with a face-centred cubic (FCC) structure in the as-cast, homogenized and recrystallized conditions was studied by determining the intrinsic response to abrasive scratch testing. For the FCC material, the wear mechanism was qualitatively the same for the as-cast, homogenized and recrystallized conditions. The wear rate increased with increasing load, and the fraction of material remov...
#1Ming Chen(TUT: Taiyuan University of Technology)H-Index: 2
#2Liwei Lan(TUT: Taiyuan University of Technology)H-Index: 1
Last. Junwei Qiao(TUT: Taiyuan University of Technology)H-Index: 29
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Abstract The microstructure, hot hardness and oxidation behavior of Al0.6CoCrFeNi high-entropy alloy were investigated. Moreover, the effect of the temperature on the tribological properties of Al0.6CoCrFeNi high-entropy alloy was studied. The results showed that the σ-CrFe phase was precipitated after heat treatment. The hardness of HEAs increased from 278 to 480 HV. The HEAs possessed higher wear resistance than that of the conventional alloys at elevated temperatures. The wear resistance of a...
Last. Ming Yang(Guida: Guizhou University)H-Index: 4
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Abstract Dry sliding wear tests of steel disks of various compositions were performed with consideration of the effects of microstructure, shear strain and shear strain rate using a ball-on-disk tester with a tungsten carbide ball under ambient atmosphere and room temperature. We found a severe–mild wear transition phenomenon, which we called self-lubrication, and categorized friction behavior into two regimes: a high-friction regime and a low-friction regime. However, self-lubrication occurs on...
#1Jinxiong Hou(TUT: Taiyuan University of Technology)H-Index: 4
#2Min Zhang(TUT: Taiyuan University of Technology)H-Index: 10
Last. Yucheng Wu(TUT: Taiyuan University of Technology)H-Index: 66
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Abstract The boronized layer was prepared on the Al0.25CoCrFeNi high-entropy alloy (HEAs) by solid-boronizing method. A 50 μm-thickness boronized layer with the phases of (Ni,Co,Fe)2B and CrB has been prepared for holding 9 h at 900 °C. Remarkably, the Vickers microhardness of the boronized sample surface approximately approaches 1136 HV, which was 6.0 times of that in the unboronized condition. Surprisingly, the boronized Al0.25CoCrFeNi alloys have better wear resistance than the unboronized on...
#1L.M. Du(TUT: Taiyuan University of Technology)H-Index: 1
#2L.W. Lan(TUT: Taiyuan University of Technology)H-Index: 2
Last. Junwei Qiao(TUT: Taiyuan University of Technology)H-Index: 29
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Abstract The tribological behavior of Al 0.25 CoCrFeNi high-entropy alloy (HEA) sliding against Si 3 N 4 ball was investigated from room temperature to 600 ℃. The microstructure of the alloys was characterized by simple FCC phase with 260 HV. Below 300 ℃, with increasing temperature, the wear rate increased due to high temperature softening. The wear rate remained stabilized above 300 ℃ due to the anti-wear effect of the oxidation film on the contact interface. The dominant wear mechanism of HEA...
#1Tulika Dixit(IITI: Indian Institute of Technology Indore)H-Index: 1
#2I. Singh(IITI: Indian Institute of Technology Indore)H-Index: 10
Last. K. Eswar Prasad(IITI: Indian Institute of Technology Indore)H-Index: 14
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Abstract Trace additions of elemental Boron to Ti-6A-4V melt has a marked influence on the as-cast microstructure and mechanical properties. In this study, dry sliding wear behavior of as-cast Ti-6Al-4V alloys containing 0%, 0.3% and 0.55% B was investigated in the temperature range of 300–573 K against the hardened steel as the counterface material. The results indicate that wear rate decreases initially with small additions of B and then increases again with subsequent additions. It is found t...
#7Jun Cheng(CAS: Chinese Academy of Sciences)H-Index: 21
Abstract null null FeCoCrNiAl high entropy alloy (HEA) matrix composite containing graphite nanoplates has been produced by spark plasma sintering (SPS). The tribological properties of this composite were tribo-tested under various loads and velocities. The results suggested that compared to the HEA, the graphite nanoplates can reduce the coefficient of friction significantly from 0.5 to 0.8 to 0.27–0.16. Under low load and velocity conditions, the reduction of friction reached 80%, and a neglig...
Abstract null null Boride layers were grown on the surface of a Co1.19Cr1.86Fe1.30Mn1.39Ni1.05Al0.17B0.04 high-entropy alloy (HEA) by boronizing at temperatures of 900, 950 and 1000°C for 4 h using nanosized boronizing powders. Characterizations were carried out by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), microhardness measurements, nanoindentation tests, surface profilometry and ball-on-disc type wear tests. The tribocorrosion beha...
Abstract null null High-entropy alloys (HEAs) with face-centered cubic (FCC) structures exhibit high toughness and corrosion resistance, but their average strengths and relatively low wear resistance can limit their engineering applications. In this study, Al0.07 Co1.26Cr1.80Fe1.42Mn1.35 Ni1.10 alloys with FCC structures were boronized for 4 h at temperatures of 900, 950, and 1000°C to form hard, protective metal borides on their surfaces. The microstructural characteristics of the borides forme...
#1Yipu Sun(TUT: Taiyuan University of Technology)H-Index: 2
#2A.D. Lan(TUT: Taiyuan University of Technology)H-Index: 5
Last. Junwei Qiao(TUT: Taiyuan University of Technology)H-Index: 29
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Abstract The passivity of CrMnFeNi and CrMnFeNiLa0.1 high entropy alloys (HEAs) in 0.5 M H2SO4 solution had been investigated by immersion test, Mott-Schottky analysis, electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). Potentiodynamic polarization and immersion tests demonstrate that CrMnFeNiLa0.1 exhibited better overall corrosion resistance than that of CrMnFeNi. Semiconducting properties of both HEAs were identified by Mott-Schottky analysis. XPS results...
#1Xujie Gao(SDUT: Shandong University of Technology)H-Index: 1
#2Liang Wang(HIT: Harbin Institute of Technology)H-Index: 139
Last. Jingjie Guo(HIT: Harbin Institute of Technology)H-Index: 25
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Abstract null null To improve the room temperature comprehensive mechanical properties of the refractory high entropy alloy Hf0.5Mo0.5NbTiZr, boron element is added to form the boride phase as the strengthening phase. The Hf0.5Mo0.5NbTiZrBx (x = 0.1, 0.3, 0.5, 0.7, and 0.9) were produced by vacuum arc melting and effect of boron element on the microstructure and room temperature mechanical properties of Hf0.5Mo0.5NbTiZr alloy was investigated. The boride MB2 phase form and the volume fraction of...
Last. Ramsey F. Hamade(AUB: American University of Beirut)H-Index: 17
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Abstract This paper aims to investigate the frictional and wear performances of natural flax fibers reinforced polypropylene composites subjected to lubricated mechanical polishing. Particularly, the interactions between the biocomposite surfaces and two different liquids (oil and water) are considered using a rotary tribometer where the counter-face is fed by silicon carbide (SiC) abrasive papers. Friction and wear at dry, water and oil-lubricated polishing are hence studied. The biocomposite w...
The wear resistance of diffusion coatings in conditions of specific pressures of 3, 7 and 10 MPa was studied. The boride coatings were prepared by means of diffusion methods using C45 steel as the substrate material. Research on the microstructure and redistribution of chemical elements on wear surface of a borided layer was carried out. It was found that the boride coatings should be used under a specific pressure of 7 MPa. It was found that the wear of friction couple coating of steel C45 unde...