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

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.

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Microstructure and Mechanical Properties of VTaTiMoAlx Refractory High Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.898.638 ◽

2017 ◽

Vol 898 ◽

pp. 638-642 ◽

Cited By ~ 7

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.

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In situ investigation of the deformation behaviors of Fe20Co30Cr25Ni25 and Fe20Co30Cr30Ni20 high entropy alloys by high-energy X-ray diffraction

Materials Science and Engineering A ◽

10.1016/j.msea.2020.139936 ◽

2020 ◽

Vol 795 ◽

pp. 139936

Author(s):

Ning Xu ◽

Shilei Li ◽

Runguang Li ◽

Minghe Zhang ◽

Zhiran Yan ◽

...

Keyword(s):

High Energy ◽

High Entropy Alloys ◽

X Ray Diffraction ◽

X Ray ◽

High Entropy ◽

In Situ Investigation ◽

Deformation Behaviors

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High-energy synchrotron X-ray diffraction measurements of simple bending of pseudoelastic NiTi shape memory alloy wires

Powder Diffraction ◽

10.1017/s0885715616000154 ◽

2016 ◽

Vol 31 (2) ◽

pp. 104-109 ◽

Cited By ~ 1

Author(s):

Baozhuo Zhang ◽

Marcus L. Young

Keyword(s):

Phase Transformation ◽

Shape Memory ◽

High Energy ◽

Bend Angle ◽

Niti Shape Memory Alloy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Mechanical Bending ◽

Xrd Patterns

Many technological applications of austenitic shape memory alloys (SMAs) involve cyclical mechanical loading and unloading in order to take advantage of pseudoelasticity. In this paper, we investigated the effect of mechanical bending of pseudoelastic NiTi SMA wires using high-energy synchrotron radiation X-ray diffraction (SR-XRD). Differential scanning calorimetry was performed to identify the phase transformation temperatures. Scanning electron microscopy images show that micro-cracks in compressive regions of the wire propagate with increasing bend angle, while tensile regions tend not to exhibit crack propagation. SR-XRD patterns were analyzed to study the phase transformation and investigate micromechanical properties. By observing the various diffraction peaks such as the austenite (200) and the martensite (${\bar 1}12$), (${\bar 1}03$), (${\bar 1}11$), and (101) planes, intensities and residual strain values exhibit strong anisotropy, depending upon whether the sample is in compression or tension during bending.

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

Acta Physica Polonica A ◽

10.12693/aphyspola.128.552 ◽

2015 ◽

Vol 128 (4) ◽

pp. 552-557 ◽

Cited By ~ 12

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

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

Metals ◽

10.3390/met12010041 ◽

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.

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XRD and Tem Characterization of Cathodic MnO2 and Discharge Products in the Li-MnO2 Cell

MRS Proceedings ◽

10.1557/proc-393-119 ◽

1995 ◽

Vol 393 ◽

Cited By ~ 1

Author(s):

Y. Shao ◽

S.A. Hackney ◽

B.C. Cornilsen

Keyword(s):

Lattice Parameter ◽

X Ray Diffraction ◽

Electrolytic Manganese Dioxide ◽

Cathodic Material ◽

X Ray ◽

Heat Treated ◽

Electrolytic Manganese ◽

Xrd Patterns ◽

Convergent Beam

ABSTRACTThe crystal structures of the undischarged, heat-treated electrolytic manganese dioxide (HEMD) and discharge products are characterized by high spatial resolution convergent beam electron diffraction (CBED). The results are compared with the x-ray diffraction (XRD) patterns characterized by broad, diffuse peaks. The CBED results for HEMD show that the starting cathodic material has the pyrolusite space group, but with a range of c/a ratios. The variability of the lattice parameter from grain to grain is found to coincide with the broadening on the low angle side of the XRD peaks. The CBED patterns of discharge products suggest a reduction range in c/a ratios and the formation of another phase.

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Synthesis and Characterization of YCrxAl1-xO3 Particles by a Reverse Micelle Processing

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.47.54 ◽

2017 ◽

Vol 47 ◽

pp. 54-59 ◽

Cited By ~ 1

Author(s):

Dae Han Lee ◽

Ji Young Ock ◽

Jeong Hoon Son ◽

Dong Sik Bae

Keyword(s):

Reverse Micelle ◽

Heating Temperature ◽

Molar Ratio ◽

Synthesis And Characterization ◽

X Ray Diffraction ◽

Inorganic Pigment ◽

X Ray ◽

Heat Treated ◽

Average Size

YCrxAl1-xO3 nanoparticles were synthesized by a reverse micelle processing for inorganic pigment. Y(NO3)2·6H2O, Cr (NO3)2·6H2O and Al (NO3)3·9H2O are used for precursors in order to synthesis YCrxAl1-xO3 nanoparticles. The aqueous solution consists of mixing the molar ratio of Y/Cr/Al at 1:x:1-x and heat treated at 900~1300°C for 2h. The average size and distribution of synthesized YCrxAl1-xO3 powders was in the range of 10-20nm and narrow, respectively. The average size of the synthesized YCrxAl1-xO3 powders increased with increasing water to surfactant molar ratio and heating temperature. The crystallinity of synthesized YCrxAl1-xO3 powder increased with increasing heating temperature. The synthesized YCrxAl1-xO3 powders were characterized by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM) and color spectrophotometer. The properties of the synthesized powders were affected by such variables as molar ratio, heating temperature etc.

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Magnetic Properties of Mg0.4Ca0.6Fe2O4 Nanoparticles Synthesized by Sol-Gel Method for Hyperthermia Treatment

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.631.193 ◽

2014 ◽

Vol 631 ◽

pp. 193-197

Author(s):

A.M. Escamilla-Pérez ◽

D.A. Cortés-Hernández ◽

J.M. Almanza-Robles ◽

D. Mantovani ◽

P. Chevallier

Keyword(s):

Magnetic Properties ◽

Sol Gel ◽

Average Diameter ◽

X Ray Diffraction ◽

Hyperthermia Treatment ◽

X Ray ◽

Transmission Electron ◽

Heat Treated ◽

Different Temperatures ◽

Xrd Patterns

Powders of Mg0.4Ca0.6Fe2O4were prepared by sol-gel using ethylene glycol and Mg, Ca and Fe nitrates as starting materials. Those powders were heat treated at different temperatures (300, 400, 500 and 600 °C) for 30 min. The materials obtained were characterized by X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). The Ca-Mg ferrite with the most appropriate magnetic properties was further analyzed by transmission electron microscopy (TEM). The heating capability of the nanoferrites was also tested via magnetic induction. The XRD patterns of these Ca-Mg ferrites showed a cubic inverse spinel structure. Furthermore, neither traces of hematite nor orthorhombic Ca ferrite phases were detected. Moreover, all the Ca-Mg ferrites are superparamagnetic and the particle size distribution of these Ca-Mg magnetic nanoparticles exhibits an average diameter within the range of 10-14 nm. The needed temperature for hyperthermia treatment was achieved at around 12 min.

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Effect of Fe on Phase Transformation of Low Temperature Cu-Al-Mn Memory Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.687.474 ◽

2011 ◽

Vol 687 ◽

pp. 474-479

Author(s):

Kun Peng Zhu ◽

Ning Hu ◽

Fu Shun Liu

Keyword(s):

Heat Treatment ◽

Phase Transformation ◽

Sharp Increase ◽

X Ray Diffraction ◽

X Ray ◽

Fe Content ◽

Heat Treated ◽

Scanning Electron ◽

Al Matrix ◽

Fe Addition

The influence of Fe addition on the phase transformation and the microstructure of Cu67Al27-XMn6FeXshape memory alloys are investigated by means of electrical resistivity, X-ray diffraction, scanning electron microscopy and microhardness test. It was shown that the Ms (Martensitic start transformation) temperature of the 850°C heat-treated alloy exhibit a sharp increase as Fe content increases, by comparison with the alloy without heat-treatment. For example, after 850°C heat-treatment, the Ms temperature of the alloy increases from 52K to 135K when Fe is added from 0 at.% to 1.5 at.%. The microstructure of as-homogenized Cu67Al27-XMn6FeXalloys consists of Cu3Al matrix, γ2(Cu9Al4) and α (Cu) phases. Fe element was distributed in precipitates and matrix.

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