scholarly journals In Situ Development and High Temperature Features of CoCrFeNi-M6Cp High Entropy-Alloy Based Hardmetal

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 408
Author(s):  
Huizhong Li ◽  
He Lin ◽  
Xiaopeng Liang ◽  
Weiwei He ◽  
Bin Liu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Volume Fraction ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Average Grain Size ◽  
Carbide Particles

In this work, an in-situ CoCrFeNi-M6Cp high entropy-alloy (HEA) based hardmetal with a composition of Co25Cr21Fe18Ni23Mo7Nb3WC2 was fabricated by the powder metallurgy (PM) method. Microstructures and mechanical properties of this HEA were characterized and analyzed. The results exhibit that this HEA possesses a two-phase microstructure consisting of the face-centered cubic (FCC) matrix phase and the carbide M6C phase. This HEA has an average grain size of 2.2 μm, and the mean size and volume fraction of carbide particles are 1.2 μm and 20%. The tensile tests show that the alloy has a yield strength of 573 MPa, ultimate tensile strength of 895 MPa and elongation of 5.5% at room temperature. The contributions from different strengthening mechanisms in this HEA were calculated. The grain boundary strengthening is the dominant strengthening mechanism, and the carbide particles are significant for the further enhancement of yield strength by the dislocation strengthening and Orowan strengthening. In addition, with increasing temperatures from 600 °C to 900 °C, the HEA shows a reduced yield strength (YS) from 473 MPa to 142 MPa, a decreased ultimate tensile strength (UTS) from 741 MPa to 165 MPa and an enhanced elongation from 10.5% to 31%.

Microstructure Refinement in the CoCrFeNiMn High Entropy Alloy under Plastic Straining

2016 ◽  
Vol 879 ◽  
pp. 1853-1858 ◽  
Author(s):  
Nikita Stepanov ◽  
Dmitry Shaysultanov ◽  
Nikita Yurchenko ◽  
Margarita Klimova ◽  
Sergey Zherebtsov ◽  
...  
Keyword(s):  
Yield Strength ◽  
Volume Fraction ◽  
Dominant Role ◽  
Mechanical Twinning ◽  
Cubic Phase ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Cryogenic Temperatures ◽  
High Entropy ◽  
Average Grain Size

The effect of plastic deformation under various conditions of the equiatomic CoCrFeNiMn alloy with single face-centered cubic phase structure was studied. The alloy was rolled at room and cryogenic temperatures, and uniaxially compressed at room temperature and temperatures of 600-1100°C with different height reductions. In addition, multiaxial forging at 900-1000°C was performed. Scanning and transmission electron microscopy, including EBSD analysis, was widely employed to characterize microstructure of the deformed alloy. At room and cryogenic temperatures, mechanical twinning and shear banding plays play dominant role in microstructure evolution. Extensive refinement of the microstructure occurs as the result of rolling with reduction of 80%. During deformation at 600-1100°C, discontinuous dynamic recrystallization takes place. The recrystallized grains size and their volume fraction increases with increase of deformation temperature. Multiaxial forging at 900-1000°C was used to produce fully recrystallized structure with average grain size of 6.7 μm. The alloy in the initial condition had low yield strength of 160 Mpa but remarkable tensile ductility of 68%. Rolling substantial increases yield strength to 1120-1290 MPa, but results in loss of ductility. After multiaxial forging the alloy has balanced combination of properties – yield strength of 280 MPa and elongation of 56%.

Friction Stir Welding of the Carbon-Doped Dual-Phase High Entropy Alloy

2021 ◽  
Vol 316 ◽  
pp. 364-368
Author(s):  
Dmitry Shaysultanov ◽  
Kazimzhon Raimov ◽  
Nikita Stepanov
Keyword(s):  
Friction Stir Welding ◽  
Volume Fraction ◽  
Cast Alloy ◽  
High Yield ◽  
High Entropy Alloy ◽  
Induction Melting ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Friction Stir ◽  
Average Grain Size

Fe49Mn30Cr10Co10C1 high entropy alloy (HEA) is produced by induction melting. The as-cast alloy is cold rolled and annealed at 900°C, to produce fine recrystallized structure before friction stir welding (FSW). The structure of the annealed alloy consists of a recrystallized face-centered cubic (fcc, γ) and hexagonal close-packed (hcp, ε) phases with volume fractions of 91% and 5%, respectively, as well as M23C6 carbides with the volume fraction of 4%. Sound weld without visible defects, such as porosity or cracks, are obtained. Friction stir welding results in a decrease in the average grain size from 7.0 to 1.9 μm in the stir zone. The volume fraction of the M23C6 carbides decreases to 1% after FSW. The alloy shows high yield strength and ultimate tensile strength of 475 MPa and 865 MPa, respectively, together with elongation of 70%.

Mechanical And Superconducting Properties Of Cu-Nb3Sn In Situ Produced Composite Wires

1981 ◽  
Vol 12 ◽  
Author(s):  
A. Kolb-Telieps ◽  
B.L. Mordike ◽  
M. Mrowiec
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Wide Temperature Range ◽  
Volume Fraction ◽  
Superconducting Properties ◽  
Temperature Range ◽  
Composite Wires ◽  
Strength And Ductility

ABSTRACTCu-Nb composite wires were produced from powder, electrolytically coated with tin and annealed to convert the Nb fibres to Nb 3Sn. The content was varied between 10 wt % and 40 wt %. The superconducting properties of the wires were determined. The mechanical properties, tensile strength, yield strength and ductility were measured as a function of volume fraction and deformation over a wide temperature range. The results are compared with those for wires produced by different techniques.

scholarly journals Prediction of Strength and Ductility in Partially Recrystallized CoCrFeNiTi0.2 High-Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 389 ◽  
Author(s):  
Hanwen Zhang ◽  
Peizhi Liu ◽  
Jinxiong Hou ◽  
Junwei Qiao ◽  
Yucheng Wu
Keyword(s):  
Tensile Strength ◽  
Single Phase ◽  
Volume Fraction ◽  
Tensile Elongation ◽  
High Entropy Alloy ◽  
High Entropy Alloys ◽  
Number Density ◽  
High Entropy ◽  
Average Size ◽  
Strength And Ductility

The mechanical behavior of a partially recrystallized fcc-CoCrFeNiTi0.2 high entropy alloys (HEA) is investigated. Temporal evolutions of the morphology, size, and volume fraction of the nanoscaled L12-(Ni,Co)3Ti precipitates at 800 °C with various aging time were quantitatively evaluated. The ultimate tensile strength can be greatly improved to ~1200 MPa, accompanied with a tensile elongation of ~20% after precipitation. The temporal exponents for the average size and number density of precipitates reasonably conform the predictions by the PV model. A composite model was proposed to describe the plastic strain of the current HEA. As a consequence, the tensile strength and tensile elongation are well predicted, which is in accord with the experimental results. The present experiment provides a theoretical reference for the strengthening of partially recrystallized single-phase HEAs in the future.

Evolution of phases during tempering of P91 steel at 760℃ for varying tempering time and their effect on microstructure and mechanical properties

2016 ◽  
Vol 231 (6) ◽  
pp. 1141-1161 ◽  
Author(s):  
C Pandey ◽  
MM Mahapatra
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Secondary Phase ◽  
Particle Spacing ◽  
Carbide Particles ◽  
Tempering Time

In the present investigation, a systematic study has been undertaken with regard to the effects of tempering time on room temperature mechanical properties of P91 (X10CrMoVNNB9-1) steel. Samples cut from P91 (X10CrMoVNNB9-1) industrial pipe were normalized at 1040 ℃ for 40 min and then tempered at 760 ℃ for different tempering times starting from 2 h to 8 h. Detailed analysis of microstructure, particle size, inter-particle spacing, and secondary phase carbide particles of the tempered samples was conducted by secondary electron microscopy technique. Optical microscopy was also utilized to characterize the tempered samples and for the measurement of grain size. In order to reveal the various phases formed during tempering of P91 (X10CrMoVNNB9-1) steel, X-ray diffraction was carried out . To study the fracture surface morphology of tensile tested and impact tested specimen field-emission scanning electron microscopy was carried out. The effect of tempering time on the microstructural parameters revealed an increase in grain size up to 4 h of tempering and then decreased because of recrystallization. The coarsening of secondary phase carbide particles M23C6 was revealed with an increase in tempering time. As a consequence, yield strength, hardness, and ultimate tensile strength were observed to decrease with increase in the tempering time. However, a drastic change was observed in the yield strength, ultimate tensile strength, and toughness after tempering for 6 h. From the present study, it was concluded that optimum combination of yield stress, ultimate tensile strength, hardness, and toughness obtained after tempering at 760 ℃ for 6 h.

scholarly journals Effect of Heat Treatment on Mechanical Properties and Microstructure Morphology of Low-Alloy High-Strength Steel

2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Strengthening Phase ◽  
Average Grain Size

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.

Effect of Bi on Microstructure and Mechanical Properties of Extruded AZ80-2Sn Magnesium Alloy

2018 ◽  
Vol 37 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Hansong Xue ◽  
Xinyu Li ◽  
Weina Zhang ◽  
Zhihui Xing ◽  
Jinsong Rao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

AbstractThe effects of Bi on the microstructure and mechanical properties of AZ80-2Sn alloy were investigated. The results show that the addition of Bi within the as-cast AZ80-2Sn alloy promotes the formation of Mg3Bi2 phase, which can refine the grains and make the eutectic phases discontinuous. The addition of 0.5 % Bi within the as-extruded AZ80-2Sn alloy, the average grain size decreases to 12 μm and the fine granular Mg17Al12 and Mg3Bi2 phases are dispersed in the α-Mg matrix. With an increase in Bi content, the Mg17Al12 and Mg3Bi2 phases become coarsened and the grain size increases. The as-extruded AZ80-2Sn-0.5 %Bi alloy has the optimal properties, and the ultimate tensile strength, yield strength and elongation are 379.6 MPa, 247.1 MPa and 14.8 %, respectively.

Microstructure and Mechanical Properties of Mg96Y3Zn1 Alloy Processed by Equal Channel Angular Pressing

2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Equal Channel Angular Pressing ◽  
Ultrafine Grains ◽  
Angular Pressing ◽  
Average Grain Size

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.

scholarly journals Laser Beam Welding of Feconicrmn High-Entropy Alloys with Preplaced Powders

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1402
Author(s):  
Ziyi Zhou ◽  
Feng Zhang ◽  
Jili Wu ◽  
Jinhong Pi ◽  
Fei Chen
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Aspect Ratio ◽  
Yield Strength ◽  
Base Alloy ◽  
Laser Beam Welding ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Engineering Practices ◽  
Equiaxed Grains

In this paper, as-annealed FeCoNiCrMn plates were laser-welded with preplaced FeCoNiCrMn and FeCoNiCrAl powders, respectively. The grains in the fusion zone of the weld with FeCoNiCrMn powder have a reduced aspect ratio compared to those without preplaced powders and the weld with FeCoNiCrAl powder presents relative equiaxed grains. The yield strength of each weld has been remarkably enhanced when referring to the base alloy, and the ultimate tensile strength of each weld with preplaced powder exceeds 80% of that of the base and the maximum reaches 88.5% when referring to the weld with preplaced FeCoNiCrMn powder. Cleavage fractography was observed in the welds. The finding of this work will service the engineering practices of high-entropy alloys.

Effects of Yttrium on Microstructure and Mechanical Properties of In Situ (Al2O3+Al3Zr)p/A356 Composites

2010 ◽  
Vol 152-153 ◽  
pp. 1083-1087
Author(s):  
Bo Wang ◽  
Yu Tao Zhao ◽  
Song Li Zhang ◽  
Gang Chen ◽  
Xiao Nong Cheng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Test Results ◽  
Microstructure And Mechanical Properties ◽  
Yttrium Addition

In-situ (Al2O3+Al3Zr)p/A356 composites were synthesized by melt reaction technology and the effects of yttrium on microstructure and mechanical properties of the composites are investigated. The results indicate that the reinforced particulates Al2O3 and Al3Zr become smaller in size with yttrium addition, the sizes are about 0.5~2μm. The distribution becomes more homogeneous, the morphologies are spheroid-shape and ellipsoid-shape, the ambitus is blunt. The mechanical properties test results show the mechanical properties of the composites are greatly enhanced. With 0.4wt.% yttrium addition, the ultimate tensile strength and yield strength of the composites reach to 388MPa and 296MPa, which are increased 35.6% and 37.0% comparing with no yttrium addition, respectively. The effect mechanisms of yttrium are discussed.

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