A Novel High-Entropy Alloy AlMgZnSnPbCuMnNi with Low Free Corrosion Potential

2013 ◽  
Vol 327 ◽  
pp. 103-107 ◽  
Author(s):  
Zhang Hua Gan ◽  
Li Ming Xu ◽  
Zhi Hong Lu ◽  
Huan Hua Zhou ◽  
Chun Hui Song ◽  
...  
Keyword(s):  
Anode Material ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
High Entropy Alloy ◽  
Electrochemical Performances ◽  
Sacrificial Anode ◽  
X Ray Diffraction ◽  
Free Corrosion Potential ◽  
High Entropy ◽  
Prepared Alloy

A novel AlMgZnSnPbCuMnNi high entropy alloy was prepared by flux melting in the atmosphere. The microstructure and the electrochemical performances of the as-prepared alloy were studied by electrochemical workstation, X-ray diffraction and scanning electron microscopy. It was found that the free corrosion potential is as low as-1.33V in the 3.5%NaCl solution in spite of the content of Al, Mg and Zn element of the high entropy alloy is far below than that of the traditional zinc or aluminum sacrificial anode material while the free corrosion current density is 2.93×10-5 A/cm2 which is close to the typical aluminum sacrificial anode material.

scholarly journals Corrosion Properties of Cr27Fe24Co18Ni26Nb5 Alloy in 1 N Sulfuric Acid and 1 N Hydrochloric Acid Solutions

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5924
Author(s):  
Chun-Huei Tsau ◽  
Po-Min Chen
Keyword(s):  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
High Entropy Alloy ◽  
Acid Solutions ◽  
Corrosion Properties ◽  
High Entropy ◽  
Hydrochloric Acid Solutions ◽  
Fcc Phase

The composition of the Cr27Fe24Co18Ni26Nb5 high-entropy alloy was selected from the FCC phase in a CrFeCoNiNb alloy. The alloy was melted in an argon atmosphere arc-furnace, followed by annealing in an air furnace. The dendrites of the alloy were in the FCC phase, and the eutectic interdendrites of the alloy comprised HCP and FCC phases. The microstructures and hardness of this alloy were examined; the results indicated that this alloy was very stable. This microstructure and hardness of the alloy almost remained the same after annealing at 1000 °C for 24 h. The polarization behaviors of Cr27Fe24Co18Ni26Nb5 alloy in 1 N sulfuric acid and 1 N hydrochloric acid solutions were measured. Both the corrosion potential and the corrosion current density of the Cr27Fe24Co18Ni26Nb5 alloy increased with increasing test temperatures. The activation energies of the Cr27Fe24Co18Ni26Nb5 alloy in these two solutions were also calculated.

scholarly journals A Study of Thin Film Resistors Prepared Using Ni-Cr-Si-Al-Ta High Entropy Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ruei-Cheng Lin ◽  
Tai-Kuang Lee ◽  
Der-Ho Wu ◽  
Ying-Chieh Lee
Keyword(s):  
Annealing Temperature ◽  
Phase Evolution ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Temperature Coefficient Of Resistance ◽  
X Ray ◽  
High Entropy ◽  
Transmission Electron ◽  
Thin Film Resistors

Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 μΩ-cm with −10 ppm/°C of temperature coefficient of resistance (TCR).

Influences of Surface Nanocrystallization Induced by High-Energy Spot Peening on Microstructure and Properties of Magnesium Alloy

2013 ◽  
Vol 690-693 ◽  
pp. 2120-2125 ◽  
Author(s):  
Li Wen Tang ◽  
Jian Sun ◽  
Jin Zhang ◽  
Xin Bing Ou ◽  
Zhi Ming Zhou
Keyword(s):  
Surface Layer ◽  
Magnesium Alloys ◽  
Corrosion Potential ◽  
Electrochemical Measurement ◽  
Corrosion Current ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Nanocrystallization ◽  
Grain Sizes

As relatively new structure materials, magnesium and its alloys demonstrated significant potential for applications in many industries. However, magnesium alloys were easy to be corroded which greatly limited their development. AZ31B and AZ91D, two widely used commercial magnesium alloys in various industries, were chosen to be produced nanostructure on the surface layer, called Surface Nanocrystallization (SNC) by High Energy Spot Peening (HESP). The microstructure was characterized by Scan Electronic Microscopy (SEM) and X-ray diffraction (XRD) in this paper. Microhardness and corrosion resistance were measured by microhardness tester and electrochemical measurement system respectively. Experimental results showed that after HESP the grain sizes in the surface layer were obviously reduced into nanoscale; microhardness was greatly increased in the treated surface, about two times as much as that of original and corrosion current density in polarization curve was evidently raised while corrosion potential changed little.

scholarly journals Peculiarities in structure formation and corrosion of cast quasicrystalline Al63Cu25Fe12 and Al63Co24Cu13 alloys in sodium chloride aqueous solution

2020 ◽  
Vol 21 (3) ◽  
pp. 530-536
Author(s):  
O. V. Sukhova ◽  
V. A. Polonskyy
Keyword(s):  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Free Corrosion Potential ◽  
X Ray ◽  
Marine Climate ◽  
Potentiodynamic Method

In this work the structure and corrosion behavior of quasicrystalline cast Al63Cu25Fe12 and Al63Co24Cu13 alloys in 5-% sodium chloride solution (рН 6.9–7.1) were investigated. The alloys were cooled at 5 К/s. The structure of the samples was studied by methods of quantitative metallography, X-ray analysis, and scanning electron microscopy. Corrosion properties were determined by the potentiodynamic method. The made investigations confirm the formation of stable quasicrystalline icosahedral (y) and decagonal (D) phases in the structure of Al63Cu25Fe12 and Al63Co24Cu13 alloys correspondingly. In 5-% sodium chloride solution, the investigated alloys corrode under electrochemical mechanisms with oxygen depolarization. Compared with Al63Cu25Fe12 alloy, Al63Co24Cu13 alloy has a less negative value of free corrosion potential (–0.43 V and–0.66 V, respectively), and its electrochemical passivity region extends due to the inhibition of anodic processes. A corrosion current density, calculated from (E,lgi)-curve, for Al63Co24Cu13 alloy amounts to 0.18 mА/сm2 and for Al63Cu25Fe12 alloy – to 0.20 mА/сm2. The lower corrosion resistance of Al63Cu25Fe12 alloy may be explained by the presence of iron-containing phases in its structure. Based on obtained results, the Al63Co24Cu13 alloy was recommended as a coating material for rocket-and-space equipment working in a marine climate.

scholarly journals Corrosion Resistance of Electrochemically Synthesized Modified Zaccagnaite LDH-Type Films on Steel Substrates

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7389
Author(s):  
Michael Kahl ◽  
Teresa D. Golden
Keyword(s):  
Corrosion Resistance ◽  
Layered Double Hydroxide ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Double Hydroxide ◽  
Double Hydroxides ◽  
Steel Substrates ◽  
Deposited Films

Modified zaccagnaite layered double hydroxide (LDH) type films were synthesized on steel substrates by pulsed electrochemical deposition from aqueous solutions. The resulting films were characterized by X-ray diffraction, scanning electron microscopy/X-ray dispersive spectroscopy, and Fourier transform infrared spectroscopy. Structural characterization indicated a pure layered double hydroxide phase; however, elemental analysis revealed that the surface of the films contained Zn:Al ratios outside the typical ranges of layered double hydroxides. Layer thickness for the deposited films ranged from approximately 0.4 to 3.0 μm. The corrosion resistance of the film was determined using potentiodynamic polarization experiments in 3.5 wt.% NaCl solution. The corrosion current density for the coatings was reduced by 82% and the corrosion potential was shifted 126 mV more positive when 5 layers of modified LDH coatings were deposited onto the steel substrates. A mechanism was proposed for the corroding reactions at the coating.

scholarly journals Design and Production of a New FeCoNiCrAlCu High-Entropy Alloy: Influence of Powder Production Method on Sintering

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4342
Author(s):  
Eduardo Reverte ◽  
Monique Calvo-Dahlborg ◽  
Ulf Dahlborg ◽  
Monica Campos ◽  
Paula Alvaredo ◽  
...  
Keyword(s):  
Atomic Radius ◽  
Production Method ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Vacuum Sintering ◽  
High Entropy ◽  
Powder Production ◽  
Production Techniques ◽  
Fcc Phase ◽  
Domain Iii

The structure of FeCoNiCrAl1.8Cu0.5 high-entropy alloys (HEA) obtained by two different routes has been studied. The selection of the composition has followed the Hume–Rothery approach in terms of number of itinerant electrons (e/a) and average atomic radius to control the formation of specific phases. The alloys were obtained either from a mixture of elemental powders or from gas-atomised powders, being consolidated in both cases by uniaxial pressing and vacuum sintering at temperatures of 1200 °C and 1300 °C. The characterization performed in the sintered samples from both types of powder includes scanning electron microscopy, X-ray diffraction, differential thermal analysis, and density measurements. It was found that the powder production techniques give similar phases content. However, the sintering at 1300 °C destroys the achieved phase stability of the samples. The phases identified by all techniques and confirmed by Thermo-Calc calculations are the following: a major Co-Ni-Al-rich (P1) BCC phase, which stays stable after 1300 °C sintering and homogenising TT treatments; a complex Cr-Fe-rich (P2) B2 type phase, which transforms into a sigma phase after the 1300 °C sintering and homogenising TT treatments; and a very minor Al-Cu-rich (P3) FCC phase, which also transforms into Domain II and Domain III phases during the heating at 1300 °C and homogenising TT treatments.

scholarly journals Effect of V and Ti on the Oxidation Resistance of WMoTaNb Refractory High-Entropy Alloy at High Temperatures

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 41
Author(s):  
Shuaidan Lu ◽  
Xiaoxiao Li ◽  
Xiaoyu Liang ◽  
Wei Yang ◽  
Jian Chen
Keyword(s):  
Oxidation Resistance ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Early Stage ◽  
Mass Gain ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy

Alloying with V and Ti elements effectively improves the strength of WMoTaNb refractory high entropy alloys (RHEAs) at elevated temperatures. However, their effects on the oxidation resistance of WMoTaNb RHEAs are unknown, which is vitally important to their application at high temperatures. In this work, the effect of V and Ti on the oxidation behavior of WMoTaNb RHEA at 1000 °C was investigated using a thermogravimetric system, X-ray diffraction and scanning electron microscopy. The oxidation of all alloys was found to obey a power law passivating oxidation at the early stage. The addition of V aggravates the volatility of V2O5, MoO3 and WO3, and leads to disastrous internal oxidation. The addition of Ti reduces the mass gain in forming the full coverage of passivating scale and prolongs the passivation duration of alloys.

Microstructure and Properties of TiB2/AlFeNiCoCr Composites by Spark Plasma Sintering

2020 ◽  
Vol 842 ◽  
pp. 83-89
Author(s):  
Dai Hong Xiao ◽  
Min Dong Wu
Keyword(s):  
Spark Plasma Sintering ◽  
Phase Evolution ◽  
High Entropy Alloy ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Alloy Matrix ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Temperature And Pressure

TiB2/AlFeNiCoCr high-entropy-alloy-matrix composites were fabricated by spark plasma sintering. Effects of SPS process on microstructure and mechanical properties of 0.5 vol.% TiB2/AlFeNiCoCr composites were studied using X-ray diffraction, density testing, scanning electron microscopy, mechanical property testing. It is shown that increasing of sintering temperature and pressure can improve the relative density and compressive properties of 5 vol. %TiB2/AlCoCrFeNi composites. During the spark plasma sintering, there is phase evolution in the composites. The 5 vol. % TiB2/AlCoCrFeNi composite after sintering at 1200 °C and 30 ~ 45 MPa is composed of phases BCC, B2, FCC, σ and TiB2.

scholarly journals Oxidation Behavior of Refractory AlNbTiVZr0.25 High-Entropy Alloy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2526 ◽  
Author(s):  
Nikita Yurchenko ◽  
Evgeniya Panina ◽  
Sergey Zherebtsov ◽  
Gennady Salishchev ◽  
Nikita Stepanov
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Breakaway Oxidation ◽  
High Entropy ◽  
Second Stage ◽  
Entire Duration ◽  
Different Temperatures ◽  
Oxidation Mechanisms

Oxidation behavior of a refractory AlNbTiVZr0.25 high-entropy alloy at 600–900 °C was investigated. At 600–700 °C, two-stage oxidation kinetics was found: Nearly parabolic oxidation (n = 0.46–0.48) at the first stage, transitioned to breakaway oxidation (n = 0.75–0.72) at the second stage. At 800 °C, the oxidation kinetics was nearly linear (n = 0.92) throughout the entire duration of testing. At 900 °C, the specimen disintegrated after 50 h of testing. The specific mass gains were estimated to be 7.2, 38.1, and 107.5, and 225.5 mg/cm2 at 600, 700, and 800 °C for 100 h, and 900 °C for 50 h, respectively. Phase compositions and morphology of the oxide scales were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the surface layer at 600 °C consisted of the V2O5, VO2, TiO2, Nb2O5, and TiNb2O7 oxides. Meanwhile, the scale at 900 °C comprised of complex TiNb2O7, AlNbO4, and Nb2Zr6O17 oxides. The oxidation mechanisms operating at different temperatures were discussed and a comparison of oxidation characteristics with the other alloys was conducted.

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