Pressure Influence on the AlCrFeNiMn/Graphite High Entropy Composite Microhardness

2017 ◽  
Vol 750 ◽  
pp. 9-14
Author(s):  
Gabriela Popescu ◽  
Mihai Branzei ◽  
Cristian Aurelian Popescu ◽  
Alecs Andrei Matei ◽  
Roxana Trusca ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
High Entropy Alloys ◽  
X Rays ◽  
High Entropy ◽  
Graphite Particles ◽  
The Matrix ◽  
Microhardness And Microstructure ◽  
Near Net Shape ◽  
Chemical Distribution ◽  
Scanning Electron

During the last years, mechanical alloying technique for high entropy alloys (HEAs) has been more often approached due to the good homogenous chemical distribution and near net shape technology provided by the respectively process. A new composite material having the matrix as HEA reinforced with graphite particles was designed. The graphite particles addition in the high entropy matrix (AlCrFeNiMn) improves the particles weldability during mechanical alloying and assures a good creep behavior for the final product. The aim of this paper is to investigate the pressure influence on the microhardness as dependence of sintering parameters which can be reflected also on the microstructure. The high entropy composite was completely alloyed after 40 hours of milling. The obtained composite was pressed using different pressures values in order to investigate the pressure influence on the microhardness and microstructure. The samples were investigated using optical microscopy, scanning electron microscopy, X-rays diffraction and microhardness tests. The microhardness values for all the samples were between 300 – 700 HV.

Compression stress strengthening modelling of a ultrafine-grained equiatomic SPS CoCrFeNiNb high-entropy alloy

2020 ◽  
pp. 095440622094324
Author(s):  
Marcello Cabibbo ◽  
Filip Průša ◽  
Alexandra Šenková ◽  
Andrea Školáková ◽  
Vojtěch Kučera ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Alloying ◽  
Oxide Phase ◽  
High Entropy Alloy ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

High-entropy alloys are known to show exceptionally high mechanical properties, both compression and tensile strength, and unique physical properties, such as their phase stability. These quite unusual properties are primarily due to the microstructure generated by mechanical alloying processes, such as conventional induction arc melting, powder metallurgy, or mechanical alloying. In the present study, an equiatomic CoCrFeNiNb high-entropy alloy was prepared by a sequence of conventional induction melting, powder metallurgy, and compaction via spark plasma sintering. The high-entropy alloys showed uniform sub-micrometer grain microstructure consisted by a mixture of an fcc solid solution strengthened by a hcp Laves phase and a third intergranular oxide phase. The as-cast high-entropy alloys showed an ultimate compression strength (UCS) of ∼1400 MPa, which after sintering and compaction at 1273 K increased up to ∼2400 MPa. Extensive transmission electron microscopy quantitative analyses were carried out to model the UCS. A quite good agreement between the microstructure-strengthening model and the experimental UCS was found.

scholarly journals Preparation of Bulk TiZrNbMoV and NbTiAlTaV High-Entropy Alloys by Powder Sintering

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1748
Author(s):  
Yaqi Wu ◽  
Peter K. Liaw ◽  
Yong Zhang
Keyword(s):  
Raw Materials ◽  
Testing Machine ◽  
Compression Rate ◽  
High Entropy Alloys ◽  
Alloy Structure ◽  
Metal Compounds ◽  
High Entropy ◽  
Universal Testing ◽  
Powder Sintering ◽  
Scanning Electron

The refractory HEAs block material was prepared by powder sintering, using an equal atomic proportion of mixed TiZrNbMoV and NbTiAlTaV metal powder raw materials. The phase was analyzed, using an XRD. The microstructure of the specimen was observed, employing a scanning electron microscope, and the compressive strength of the specimen was measured, using an electronic universal testing machine. The results showed that the bulk cubic alloy structure was obtained by sintering at 1300 °C and 30 MPa for 4 h, and a small amount of complex metal compounds were contained. According to the pore distribution, the formed microstructure can be divided into dense and porous zones. At a compression rate of 10−4s−1, the yield strengths of TiZrNbMoV and NbTiAlTaV alloys are 1201 and 700 MPa, respectively.

Synthesis of CuCrFeNiTiAlx high entropy alloys by means of mechanical alloying and spark plasma sintering

2021 ◽  
pp. 1-9
Author(s):  
Gabriela E. Ruiz-Jasso ◽  
Sebastián Díaz-de la Torre ◽  
Ricardo Escalona-González ◽  
J. Claudio Méndez-García ◽  
José A. Castillo Robles ◽  
...  
Keyword(s):  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Plasma Sintering ◽  
Spark Plasma

Processing and Consolidation of Nanocrystalline Cu-Zn-Ti-Fe-Cr High-Entropy Alloys via Mechanical Alloying

2013 ◽  
Vol 44 (10) ◽  
pp. 4532-4541 ◽  
Author(s):  
Sanghita Mridha ◽  
Sumanta Samal ◽  
P. Yousaf Khan ◽  
Krishanu Biswas ◽  
Govind
Keyword(s):  
Mechanical Alloying ◽  
High Entropy Alloys ◽  
High Entropy

scholarly journals Evaluation of Radiation Response in CoCrFeCuNi High-Entropy Alloys

Entropy ◽  
2018 ◽  
Vol 20 (11) ◽  
pp. 835 ◽  
Author(s):  
Yang Wang ◽  
Kun Zhang ◽  
Yihui Feng ◽  
Yansen Li ◽  
Weiqi Tang ◽  
...  
Keyword(s):  
Ion Irradiation ◽  
Ion Beam ◽  
High Entropy Alloys ◽  
X Ray Diffraction ◽  
Thermal Spike ◽  
High Entropy ◽  
Arc Melting ◽  
The Matrix ◽  
Volume Swelling

CoCrFeCuNi high-entropy alloys (HEAs) prepared by arc melting were irradiated with a 100 keV He+ ion beam. Volume swelling and hardening induced by irradiation were evaluated. When the dose reached 5.0 × 1017 ions/cm2, the Cu-rich phases exhibited more severe volume swelling compared with the matrix phases. This result indicated that the Cu-rich phases were favorable sites for the nucleation and gathering of He bubbles. X-ray diffraction indicated that all diffraction peak intensities decreased regularly. This reduction suggested loosening of the irradiated layer, thereby reducing crystallinity, under He+ ion irradiation. The Nix-Gao model was used to fit the measured hardness in order to obtain a hardness value H0 that excludes the indentation size effect. At ion doses of 2.5 × 1017 ions/cm2 and 5.0 × 1017 ions/cm2, the HEAs showed obvious hardening, which could be attributed to the formation of large amounts of irradiation defects. At the ion dose of 1.0 × 1018 ions/cm2, hardening was reduced, owing to the exfoliation of the original irradiation layer, combined with recovery induced by long-term thermal spike. This study is important to explore the potential uses of HEAs under extreme irradiation conditions.

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