Understanding Disordered Multicomponent Solid Solutions or High Entropy Alloys Using X-Ray Diffraction

2020 ◽  
pp. 329-354
Author(s):  
Anandh Subramaniam ◽  
Rameshwari Naorem ◽  
Anshul Gupta ◽  
Sukriti Mantri ◽  
K.V. Mani Krishna ◽  
...  
Keyword(s):  
Solid Solutions ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy

Microstructure and Mechanical Properties of VTaTiMoAlx Refractory High Entropy Alloys

2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
Dendrite Structure ◽  
X Ray ◽  
High Entropy ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Microstructure And Mechanical Properties

A series of refractory high-entropy alloys VTaTiMoAlx with x=0,0.2,0.6,1.0 were designed and produced by vacuum arc melting. The effect of added Al elements on the microstructure and mechanical properties of refractory high-entropy alloys were investigated. The X-ray diffraction results showed that all the high-entropy alloys consist of simple BCC solid solution. SEM indicated that the microstructure of VTaTiMoAlx changes from equiaxial dendritic-like structure to typical dendrite structure with the addition of Al element. The composition of different regions in the alloys are obtained by energy dispersive spectroscopy and shows that Ta, Mo elements are enriched in the dendrite areas, and Al, Ti, V are enriched in inter-dendrite areas. The yield strength and compress strain reach maximum (σ0.2=1221MPa, ε=9.91%) at x=0, and decrease with the addition of Al element at room temperature. Vickers hardness of the alloys improves as the Al addition.

scholarly journals Crystalline Structures of Some High Entropy Alloys Obtained by Neutron and X-Ray Diffraction

2015 ◽  
Vol 128 (4) ◽  
pp. 552-557 ◽  
Author(s):  
U. Dahlborg ◽  
J. Cornide ◽  
M. Calvo-Dahlborg ◽  
T.C. Hansen ◽  
Z. Leong ◽  
...  
Keyword(s):  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystalline Structures ◽  
High Entropy

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.

Evolution of Microstructures and Properties of the AlxCrCuFeNi2 High-Entropy Alloys

2013 ◽  
Vol 745-746 ◽  
pp. 706-714 ◽  
Author(s):  
Sheng Guo Ma ◽  
Zhao Di Chen ◽  
Yong Zhang
Keyword(s):  
Phase Transformation ◽  
Cast Alloy ◽  
Alloy System ◽  
Molar Ratio ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy ◽  
Heat Treated ◽  
Xrd Patterns

The microstructure and Vickers hardness of the AlxCrCuFeNi2(x=0.5, 1.0, and 2.0 in molar ratio) high-entropy alloys with as-cast and heat-treated states were investigated. X-ray diffraction (XRD) patterns suggested that for the Al0.5 alloy annealed at 900,an incomplete phase transformation from FCC to BCC occurred, while for the Al2.0 alloy as heated at 500 and 700, a converse phase transformation from BCC to FCC was obtained. Compared with the as-cast dendrites, after heat treatment, the microstructure of the alloys was obviously coarsened or spheroidized or homogenized, whereas the resultant hardness has almost not decreased even at high heating temperatures, which indicated the probability of ordering for this alloy system and thus effectively compensating the stress and structural relaxations. The Al2.0 alloy reached the maximum hardness value of 610 HV by annealing at 1100, which might be ascribed to the worm-like nanoprecipitations and the enhanced fraction of B2-ordered precipitations. By cold rolling, the Al0.5 alloy is able to reach the yield strength of 1055 MPa and the fracture strength of 1179 MPa, which was a significant improvement in comparison with the as-cast alloy.

Effect of Aluminum Addition on AlxCoFeMnNiZn Multi-Component Production

2017 ◽  
Vol 751 ◽  
pp. 53-59 ◽  
Author(s):  
Amnart Suksamran ◽  
Nawarat Worauaychai ◽  
Nattaya Tosangthum ◽  
Thanyaporn Yodkaew ◽  
Rungtip Krataitong ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Melting Process ◽  
Core Shell ◽  
High Entropy Alloys ◽  
Dendritic Solidification ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Entropy ◽  
Core Shell Structure ◽  
Scanning Electron

Five multi-component alloy (MCA) formulations of CoFeMnNiZn (MCA01), Al0.5CoFeMnNiZn (MCA02), Al1.0CoFeMnNiZn (MCA03), Co5Fe5Mn30Ni20Zn40 (MCA04) and Al8.4Co4.6Fe4.6Mn27Ni18.4Zn37 (MCA05) were prepared by mechanical alloying and melting process (MAM). Five-component alloys of MCA01-MCA05 were designed using empirical formulae for high entropy alloys. Phase formation and microstructure were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that MCA01 was partially melted by MAM process. However, MCA02-MCA05 could be melted and cast by MAM process. The microstructures of as-cast MCA02 and MCA03 showed dendritic solidification. Nevertheless, the as-cast MCA04 showed microstructure similar to that of Ni-based superalloy, i.e., the as-cast MCA04 consisted of γ matrix and γ′ phase. Moreover, egg type core shell structure was found in the interdendritic regions of the MCA05 alloy. In addition, the Al-added MCA02 and MCA03 alloys showed crystal structures of FCC1, FCC2 and BCC. MCA04 alloy demonstrated crystal structure of FCC whereas MCA05 alloy had crystal structures of FCC and Primitive Cubic.

scholarly journals Preparation of high-entropy carbides by different sintering techniques

2021 ◽  
Vol 56 (19) ◽  
pp. 11237-11247 ◽  
Author(s):  
Johannes Pötschke ◽  
Manisha Dahal ◽  
Mathias Herrmann ◽  
Anne Vornberger ◽  
Björn Matthey ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Vacuum Sintering ◽  
X Ray ◽  
High Entropy ◽  
Mean Grain Size ◽  
The Mean ◽  
Gas Pressure Sintering ◽  
Hardness Values

AbstractDense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

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).

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