Corrosion of Al CoCrFeNi high-entropy alloys: Al-content and potential scan-rate dependent pitting behavior

2017 ◽  
Vol 119 ◽  
pp. 33-45 ◽  
Author(s):  
Yunzhu Shi ◽  
Bin Yang ◽  
Xie Xie ◽  
Jamieson Brechtl ◽  
Karin A. Dahmen ◽  
...  
Keyword(s):  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content ◽  
Rate Dependent ◽  
Scan Rate

Effect of Al content on high temperature oxidation resistance of AlxCoCrCuFeNi high entropy alloys (x=0, 0.5, 1, 1.5, 2)

Vacuum ◽  
2019 ◽  
Vol 169 ◽  
pp. 108837 ◽  
Author(s):  
Y.Y. Liu ◽  
Z. Chen ◽  
Y.Z. Chen ◽  
J.C. Shi ◽  
Z.Y. Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
High Entropy Alloys ◽  
Temperature Oxidation ◽  
High Entropy ◽  
Al Content

scholarly journals Generalized Stacking Fault Energy of Al-Doped CrMnFeCoNi High-Entropy Alloy

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 59 ◽  
Author(s):  
Xun Sun ◽  
Hualei Zhang ◽  
Wei Li ◽  
Xiangdong Ding ◽  
Yunzhi Wang ◽  
...  
Keyword(s):  
Interfacial Energy ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Al Content ◽  
Generalized Stacking Fault ◽  
Generalized Stacking Fault Energy

Using first-principles methods, we investigate the effect of Al on the generalized stacking fault energy of face-centered cubic (fcc) CrMnFeCoNi high-entropy alloy as a function of temperature. Upon Al addition or temperature increase, the intrinsic and extrinsic stacking fault energies increase, whereas the unstable stacking fault and unstable twinning fault energies decrease monotonously. The thermodynamic expression for the intrinsic stacking fault energy in combination with the theoretical Gibbs energy difference between the hexagonal close packed (hcp) and fcc lattices allows one to determine the so-called hcp-fcc interfacial energy. The results show that the interfacial energy is small and only weakly dependent on temperature and Al content. Two parameters are adopted to measure the nano-twinning ability of the present high-entropy alloys (HEAs). Both measures indicate that the twinability decreases with increasing temperature or Al content. The present study provides systematic theoretical plasticity parameters for modeling and designing high entropy alloys with specific mechanical properties.

scholarly journals Comparative EIS Study of AlxCoCrFeNi Alloys in Ringer’s Solution for Medical Instruments

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 928
Author(s):  
Pedro P. Socorro-Perdomo ◽  
Néstor R. Florido-Suárez ◽  
Ionelia Voiculescu ◽  
Julia C. Mirza-Rosca
Keyword(s):  
Corrosion Resistance ◽  
Passive Film ◽  
Time Constant ◽  
Equivalent Circuits ◽  
High Entropy Alloys ◽  
Impedance Spectra ◽  
High Entropy ◽  
Al Content ◽  
Medical Instruments ◽  
Very High

Depending on the properties required for the medical instruments, compared with the classical materials, the high-entropy alloys (HEAs) are a versatile option. Electrochemical Impedance Spectroscopy (EIS) measurements have been performed on AlxCoCrFeNi-type high-entropy alloys with various concentrations of Al content (x = 0.6, 0.8, and 1.0) in order to characterize their passive film and corrosion resistance at 37 °C under infectious simulated physiological conditions (Ringer´s solution acidulated with HCl) at pH = 3. The impedance spectra were obtained at different potential values between −0.7 and +0.7 V vs. SCE. Analysis of the impedance spectra was carried out by fitting different equivalent circuits to the experimental data. Two equivalent circuits, with one time constant and two time constants respectively, can be satisfactorily used for fitting the spectra: one time constant represents the characteristics of the compact passive film, and the second one is for the porous passive film. With the decreasing of Al content, the obtained EIS results are correlated with the evolution of the microhardness and microstructure, which is characterized by Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-Ray Spectroscopy (EDAX). It can be observed for all alloys that the resistance of the passive film is very high and decreases with the potential: the very high resistance of the passive film implies a high corrosion resistance, which can be assigned to the formation of the protective oxide layer and demonstrates that the analyzed alloys fulfill the prerequisites for their use as new materials for the manufacturing of medical instruments.

scholarly journals Effect of Al Content on Magnetic Properties and Thermal Expansion of As-Cast High-Entropy Alloys Al$_{x}$FeCoNiCuCr

2016 ◽  
Vol 37 (7) ◽  
pp. 987-1000 ◽  
Author(s):  
V. M. Nadutov ◽  
◽  
S. Yu. Makarenko ◽  
Ye. O. Svystunov ◽  
◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Thermal Expansion ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content

Effect of Al content on the thermal oxidation behaviour of AlHfMoNbTi high-entropy alloys analysed by in situ environmental TEM

2021 ◽  
pp. 109711
Author(s):  
Xiaomeng Yang ◽  
Zibing An ◽  
Yadi Zhai ◽  
Xin Wang ◽  
Yanhui Chen ◽  
...  
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Behaviour ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content ◽  
Environmental Tem

Effect of Al content on structure and mechanical properties of the AlxCrNbTiVZr (x=0; 0.25; 0.5; 1) high-entropy alloys

2016 ◽  
Vol 121 ◽  
pp. 125-134 ◽  
Author(s):  
N.Yu. Yurchenko ◽  
N.D. Stepanov ◽  
D.G. Shaysultanov ◽  
M.A. Tikhonovsky ◽  
G.A. Salishchev
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Al Content

High-entropy alloys in light transition metal systems

2014 ◽  
Vol 70 (a1) ◽  
pp. C943-C943
Author(s):  
Roksolana Kozak ◽  
Walter Steurer
Keyword(s):  
Single Phase ◽  
Elevated Temperatures ◽  
High Hardness ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
High Entropy ◽  
Mixing Entropy ◽  
Al Content ◽  
New Class ◽  
Arc Melting

High-entropy alloys (HEAs) are a new class of alloys designed with the approach of maximization of configurational mixing entropy by increasing the number of constituents [1,2]. Alloys produced in such a way are reported for a variety of promising properties (high hardness and strength, wear resistance, magnetism etc.) [3]. However, origin of these properties (microstructure, phase content, element composition, thermal history) is not always clear. High mixing entropy in HEAs favours the formation of single-phase substitutional solid solutions at elevated temperatures with approximately equiatomic compositions and simple average crystal structures of either the cF4-Cu (fcc) or the cI2-W (bcc). Nevertheless, only a few element combinations produce truly single-phase materials. In order to search for new HEAs compositions samples in the systems Cr-Fe-Co-Ni-Al and Cr-Fe-Co-Ni-Mn were synthesized by arc melting and homogenized in tantalum ampoules at 1100 and 1300 °C for 2 weeks. DTA, X-ray diffraction and electron microscopy measurements were performed. Only samples with small Al content (~ 5 at.%) showed the single-phase microstructure. Their local atomic structure is under investigation.

Microstructure and Properties of Multi-Component AlxCoCrFeNiTi0.5 High-Entropy Alloys

2013 ◽  
Vol 745-746 ◽  
pp. 775-780 ◽  
Author(s):  
Yong Dong ◽  
Yi Ping Lu ◽  
Jun Jia Zhang ◽  
Ting Ju Li
Keyword(s):  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Test Results ◽  
High Entropy ◽  
Solid Solution Strengthening ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Solution Strengthening ◽  
Bcc Phase

The multi-component AlxCoCrFeNiTi0.5 (x=0, 0.2, 0.5, 0.8, 1.0) high-entropy alloys were prepared by vacuum arc melting. The microstructure and mechanical properties were studied. It was found that the structure transformed from FCC into FCC + BCC + Laves, and finally into BCC with the increase of Al content. The compress test results showed that with the addition of aluminium from 0 to 1.0, the fraction strength increased while plasticity reduced. In the stain rates of 5×10-3/s and 1×10-3/s, when x=0.8 the fraction strength achieved maximum and x=0 the plastic was best, the strength of 2879MPa and 2433MPa, the strain of 0.21 and 0.22, respectively. The hardness increased obviously (from Hv479.1 to Hv692.7) when Bcc phase and Laves phase appeared. The analysis revealed that the strengthen mechanism was mainly composed of solid solution strengthening and precipitation strengthening.

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