Microstructural Evolution and Mechanical Properties in a Mn1.05Fe1.05CoNiCu0.9 High Entropy Alloy

2017 ◽  
Vol 737 ◽  
pp. 44-49 ◽  
Author(s):  
Seung Min Oh ◽  
Sun Ig Hong
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
Cast Alloy ◽  
High Entropy Alloy ◽  
Microstructural Stability ◽  
Dendrite Structure ◽  
High Entropy ◽  
Melting Temperatures ◽  
The Matrix ◽  
Fcc Structure

In the present study, the microstructural stability and mechanical properties of a MnFeCoNiCu alloy in which Cr was replaced by Cu from Cantor composition (CoCrFeMnNi) was studied. In the as-cast alloy, the dendrite arms are enriched with Cu and Mn and matrix between dendrite arms is enriched with Fe and Co. Ni was richer in the matrix, but also observed in the dendrite arms. Cu and Mn tend to segregate and solidify initially because the melting temperatures of Cu and Mn are lower than Fe and Co, resulting in the growth of Cu-Mn dendrite. After homogenization, the dendrites structure disappeared and grain boundaries are visible, indicating the segregated elements in the dendrite structure were homogenized. The presence of single phase FCC structure was confirmed after homogenization. The tensile strength of 1220 MPa with the ductility of 6 % was obtained in MnFeCoNiCu alloy.

Development of Single-Phase Bcc UHfNbTi High-Entropy Alloy with Excellent Mechanical Properties

2021 ◽  
Author(s):  
J. Shi ◽  
Y.W. Zhao ◽  
Chunli Jiang ◽  
Y.Z. Zhang ◽  
Dongli Zou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

Microstructure and Mechanical Properties of W-High Entropy Alloy Composite by Hot Swaging

2021 ◽  
Vol 871 ◽  
pp. 3-8
Author(s):  
Rui Zhi Jian ◽  
Shang Cheng Zhou ◽  
Yun Fei Xue
Keyword(s):  
Mechanical Properties ◽  
Dynamic Compression ◽  
Axial Direction ◽  
High Entropy Alloy ◽  
Degree Of Deformation ◽  
High Entropy ◽  
The Matrix ◽  
Compression Yield Strength ◽  
Reduction In Area ◽  
Strengthening Method

To improve the mechanical properties of a sintered WHA using high entropy alloy as the matrix (W-HEA), investigations were carried out to apply deformation strengthening method of hot swaging on the W-HEA. The W-HEA samples were swaged around 1300°C with the 10%, 15% and 20% of reduction in area. The results show that the strength and hardness of the W-HEA composite increased with the increasing degree of deformation. And the aspect ratio of tungsten grains increases along the axial direction in the swaged alloys. The hardness of W-HEA with a 20% reduction in area reaches 448 HV, and the dynamic compression yield strength is about 1911 MPa. After hot swaging, the hardness and strength of the W-HEA are greatly improved compared with the sintered W-HEA.

Microstructure and Mechanical Properties of Equitomic CoCrFeCuNi High Entropy Alloy

2018 ◽  
Vol 765 ◽  
pp. 149-154 ◽  
Author(s):  
Seung Min Oh ◽  
Sun Ig Hong
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Cold Rolling ◽  
Cast Alloy ◽  
Cold Work ◽  
High Entropy Alloy ◽  
Second Phase ◽  
Rich Phase ◽  
High Entropy ◽  
Microstructure And Mechanical Properties

Microstructure and mechanical properties of cast and cold-rolled equitomic CoCrFeCuNi alloy in which Mn was substituted by Cu from Cantor alloy was studied. The separation into two solid solutions (Cr-Co-Fe rich and Cu-rich phases) were observed in CoCrFeCuNi. Coarsening and widening of interdendritic Cu-rich phase after homogenization was observed after homogenization, suggesting Cu-rich phase is thermodynamically stable. The compressive stress-strain curves of homogenized cast CoCrFeCuNi alloy exhibited the reasonably high strength and excellent deformability for the cast alloy. The yield strength increased up to 960MPa after cold rolling from 265MPa of the homogenized cast alloy. The significant increase of yield strength is thought to be associated with the alignment of Cu-rich second phase in addition to cold work dislocation storage after cold rolling.

scholarly journals Elastic, Mechanical and Thermophysical properties of Single-Phase Quaternary ScTiZrHf High-Entropy Alloy

2021 ◽  
Vol 22 (4) ◽  
pp. 687-696
Author(s):  
Sachin Rai ◽  
Navin Chaurasiya ◽  
Pramod K. Yadawa
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Room Temperature ◽  
Single Phase ◽  
Mechanical Characterization ◽  
Ultrasonic Attenuation ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Different Temperatures ◽  
Ultrasonic Parameters

Consequent to the interaction potential model, the high-order elastic constants at high entropy alloys in single-phase quaternary ScTiZrHf have been calculated at different temperatures. Elastic constants of second order (SOECs) helps to determine other ultrasonic parameters. With the help of SOECs other elastic moduli, bulk modulus, shear modulus, Young’s modulus, Pugh’s ratio, elastic stiffness constants and Poisson’s ratio are estimated at room temperature for elastic and mechanical characterization. The other ultrasonic parameters are calculated at room temperature for elastic and mechanical characterization. The temperature variation of ultrasonic velocities along the crystal's z-axis is evaluated using SOECs. The temperature variation of the  average debye velocity and the thermal relaxation time (τ) are also estimated along this orientation axis. The ultrasonic properties correlated with elastic, thermal and mechanical properties which is temperature dependent is also discussed. The ultrasonic attenuation due to phonon – phonon (p-p) interactions is also calculated at different temperatures. In the study of ultrasonic attenuation such as a function of temperature, thermal conductivity appears to be main contributor and p- p interactions are the responsible reason of attenuation and found that the mechanical properties of the high entropy alloy ScTiZrHf are superior at room temperature.

scholarly journals Effects of Annealing on Microstructure and Mechanical Properties of Metastable Powder Metallurgy CoCrFeNiMo0.2 High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 448 ◽  
Author(s):  
Cui Zhang ◽  
Bin Liu ◽  
Yong Liu ◽  
Qihong Fang ◽  
Wenmin Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Volume Fraction ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Large Volume Fraction ◽  
The Matrix ◽  
Coarse Precipitation ◽  
Precipitation Enhancement ◽  
Precipitation Phase

A CoCrFeNiMo0.2 high entropy alloy (HEA) was prepared through powder metallurgy (P/M) process. The effects of annealing on microstructural evolution and mechanical properties of P/M HEAs were investigated. The results show that the P/M HEA exhibit a metastable FCC single-phase structure. Subsequently, annealing causes precipitation in the grains and at the grain boundaries simultaneously. As the temperature increases, the size of the precipitates grows, while the content of the precipitates tends to increase gradually first, and then decrease as the annealing temperature goes up to 1000 °C. As the annealing time is prolonged, the size and content of the precipitates gradually increases, eventually reaching a saturated stable value. The mechanical properties of the annealed alloys have a significant correspondence with the precipitation behavior. The larger the volume fraction and the size of the precipitates, the higher the strength and the lower the plasticity of the HEA. The CoCrFeNiMo0.2 high entropy alloy, which annealed at 800 °C for 72 h, exhibited the most excellent mechanical properties with the ultimate tensile strength of about 850 MPa and an elongation of about 30%. Nearly all of the annealed HEAs exhibit good strength–ductility combinations due to the significant precipitation enhancement and nanotwinning. The separation of the coarse precipitation phase and the matrix during the deformation process is the main reason for the formation of micropores. Formation of large volume fraction of micropores results in a decrease in the plasticity of the alloy.

scholarly journals Spinodal Decomposition and Mechanical Response of a TiZrNbTa High-Entropy Alloy

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3508 ◽  
Author(s):  
Liu ◽  
Huang ◽  
Chuang ◽  
Chou ◽  
Wei ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Spinodal Decomposition ◽  
Mechanical Response ◽  
Cast Alloy ◽  
High Entropy Alloy ◽  
Body Centered Cubic ◽  
High Entropy ◽  
Bcc Structure ◽  
20 Nm ◽  
Interconnected Structure

In this study, the effects of spinodal decomposition on the microstructures and mechanical properties of a TiZrNbTa alloy are investigated. The as-cast TiZrNbTa alloy possesses dual phases of TiZr-rich inter-dendrite (ID) and NbTa-rich dendrite (DR) domains, both of which have a body-centered cubic (BCC) structure. In the DRs of the as-cast alloy, the α and ω precipitates are found to be uniformly distributed. After homogenization at 1100 °C for 24 h followed by water quenching, spinodal decomposition occurs and an interconnected structure with a wavelength of 20 nm is formed. The α and ω precipitates remained in the structure. Such a fine spinodal structure strengthens the alloy effectively. Detailed strengthening calculations were conducted in order to estimate the strengthening contributions from the α and ω precipitates, as well as the spinodal decomposition microstructure.

Development of single-phase bcc UHfNbTi high-entropy alloy with excellent mechanical properties

2021 ◽  
pp. 130822
Author(s):  
J. Shi ◽  
Y.W. Zhao ◽  
C.L. Jiang ◽  
X. Wang ◽  
Y.Z. Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Single Phase ◽  
High Entropy Alloy ◽  
High Entropy

Microstructure and Mechanical Properties of the W-Ni-Co System Refractory High-Entropy Alloys

2015 ◽  
Vol 816 ◽  
pp. 324-329 ◽  
Author(s):  
Hui Jiang ◽  
Li Jiang ◽  
Yi Ping Lu ◽  
Tong Min Wang ◽  
Zhi Qiang Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vacuum Arc ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Melting Temperatures ◽  
Arc Melting ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Face Centered

The elements Mo, Cr and V were added to the W-Ni-Co system high entropy alloys, the effects of these added elements on microstructure and mechanical properties of these alloys were studied. The alloys were produced by vacuum arc melting. The compositions were W0.5Ni2Co2VMo0.5,W0.5Ni2Co2VCr0.5and W0.5Ni2Co2CrMo0.5(denoted as Alloy 1, Alloy 2 and Alloy 3) respectively. The theoretical melting temperatures were higher than 2000 K. X-ray diffraction, SEM and energy dispersive spectroscopy (EDS) results indicated that the matrix of the alloys is face-centered cubic (FCC) solid-solution, the alloys showed dendrite crystal structure. Ni, Co elements were enriched in the dendrite areas, the W, Mo were enriched in the inter-dendrite regions ,while V, Cr elements were uniform distribution. The Vickers hardness of these alloys was 376.1 HV, 255.88 HV and 306.8 HV, respectively. The yield strength values (σ0.2) of Alloy 1, Alloy 2 and Alloy 3 were approximately 1000MPa, 750MPa, 250MPa, respectively. The alloys show good compression plasticity deformation capacity at RT.

scholarly journals Age Heat Treatment of Al0.5CoCrFe1.5NiTi0.5 High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 91
Author(s):  
Che-Fu Lee ◽  
Tao-Tsung Shun
Keyword(s):  
Cast Alloy ◽  
Dendritic Structure ◽  
Age Hardening ◽  
High Entropy Alloy ◽  
Σ Phase ◽  
High Entropy ◽  
The Matrix ◽  
B2 Phase ◽  
Fcc Phase ◽  
Bcc Phase

In this study, Al0.5CoCrFe1.5NiTi0.5 high-entropy alloy was heat-treated from 500 °C to 1200 °C for 24 h to investigate age-hardening phenomena and microstructure evolution. The as-cast alloy, with a hardness of HV430, exhibited a dendritic structure comprising an (Fe,Cr)-rich FCC phase and a (Ni,Al,Ti)-rich B2 phase, and the interdendrite exhibited a spinodal decomposed structure comprising an (Fe,Cr)-rich BCC phase and a (Ni,Al,Ti)-rich B2 phase. Age hardening and softening occurred at 500 °C to 800 °C and 900 °C to 1100 °C, respectively. We observed optimal age hardening at 700 °C, and alloy hardness increased to HV556. The hardening was attributed to the precipitation of the σ phase, and the softening was attributed to the dissolution of the σ phase back into the matrix and coarsening of the microstructure. The appearance of fine Widmanstätten precipitates formed by the (Al,Ti)-rich BCC phase and (Ni,Al,Ti)-rich B2 phase at 1200 °C led to secondary hardening.

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