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.

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 Effect of Enhanced Gravity on the Microstructure and Mechanical Properties of Al0.9CoCrFeNi High-Entropy Alloy

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1318
Author(s):  
Anjun Shi ◽  
Ruixuan Li ◽  
Yong Zhang ◽  
Zhe Wang ◽  
Zhancheng Guo
Keyword(s):  
Mechanical Properties ◽  
The Body ◽  
Grain Structure ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Microstructure And Mechanical Properties ◽  
Gravity Fields ◽  
Bcc Structure ◽  
Strength And Plasticity ◽  
Gravity Acceleration

The influence of enhanced gravity on the microstructure and mechanical properties of the Al0.9CoCrFeNi high-entropy alloy, which was solidified under normal gravity (acceleration 1 g) and enhanced gravity (acceleration 140 g, acceleration 210 g, and acceleration 360 g) conditions is reported in this paper. Its solidification under enhanced gravity fields resulted in refinement of the columnar nondendritic grain structure and an increase in the area fraction of the body-centered cubic (BCC) structure phases. The mass transfer strengthened by enhanced gravity promoted element diffusion and enrichment, which caused changes in the composition and microstructure that, in turn, affected the mechanical properties of the alloy. The compressive strength and plasticity of the sample solidified at acceleration 360 g were equal to 2845 MPa and 36.4%, respectively, which are the highest values reported to date for Al0.9CoCrFeNi alloy.

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.

scholarly journals Thermal Stability of MoNbTaVW High Entropy Alloy Thin Films

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 941
Author(s):  
Ao Xia ◽  
Robert Franz
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
Body Centered Cubic ◽  
High Entropy ◽  
Thermal Stability Of

Refractory high entropy alloys are an interesting material class because of their high thermal stability, decent electrical conductivity, and promising mechanical properties at elevated temperature. In the present work, we report on the thermal stability of body-centered cubic MoNbTaVW solid solution thin films that were synthesized by cathodic arc deposition. After vacuum annealing up to 1600 °C, the morphology, chemical composition, crystal structure, and electrical conductivity, as well as the mechanical properties, were analyzed. The observed body-centered cubic MoNbTaVW solid solution phase is stable up to 1500 °C. The evolution of electrical and mechanical properties due to the annealing treatment is discussed based on the observed structural changes of the synthesized thin films.

Microstructure and Mechanical Properties of Equiatomic CrMnCoNiCu High Entropy Alloy

2017 ◽  
Vol 909 ◽  
pp. 39-43 ◽  
Author(s):  
Seung Min Oh ◽  
Sun Ig Hong
Keyword(s):  
Mechanical Properties ◽  
Cast Alloy ◽  
True Strain ◽  
Peak Height ◽  
Mixing Enthalpy ◽  
High Entropy Alloy ◽  
Solid Solution Phase ◽  
Rich Phase ◽  
High Entropy ◽  
Microstructure And Mechanical Properties

Microstructure and mechanical properties of equiatomic CrMnCoNiCu alloy in which Fe was substituted by Cu from Cantor alloy was studied. The separation of solid solution phase into two solid solutions (Cr-Co rich and Cu-rich phases) were observed in CrMnCoNiCu. The coarsening and widening of interdendritic Cu-rich phase after homogenization was observed and supported by the increase of XRD peak height from Cu-rich phase compared to that from Cr-Co rich phase after homogenization. The increase of the peak from Cu-rich phase can be attributed to the thermodynamic stability of Cu due to positive mixing enthalpy of adding Cu. The stress-strain curves of CrMnCoNiCu alloy exhibited the reasonably high strength and excellent deformability for the cast alloy. The yield stress of CrMnCoNiCu was observed to be 390MPa and it could be deformed without crack formation up to the true strain 0.85 to reach the flow stress as high as 662Mpa.

scholarly journals Effect of Heat Treatment on the Microstructure, Phase Distribution, and Mechanical Properties of AlCoCuFeMnNi High Entropy Alloy

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Gulhan Cakmak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Yield Strength ◽  
Phase Distribution ◽  
Cast Alloy ◽  
Lattice Parameters ◽  
High Entropy Alloy ◽  
Second Phase ◽  
High Entropy ◽  
Heat Treated

The present paper reports the synthesis of AlCoCuFeMnNi high entropy alloy (HEA) with arc melting process. The as-cast alloy was heat treated at 900°C for 8 hours to investigate the effect of heat treatment on the structure and properties. Microstructural and mechanical properties of the alloy were analyzed together with the detailed phase analysis of the samples. The initially as-cast sample was composed of two separate phases with BCC and FCC structures having lattice parameters of 2.901 Å and 3.651 Å, respectively. The heat-treated alloy displays microsized rod-shaped precipitates both in the matrix and within the second phase. Rietveld refinement has shown that the structure was having three phases with lattice parameters of 2.901 Å (BCC), 3.605 Å (FCC1), and 3.667 Å (FCC2). The resulting phases and distribution of phases were also confirmed with the TEM methods. The alloys were characterized mechanically with the compression and hardness tests. The yield strength, compressive strength, and Vickers hardness of the as-cast alloy are 1317 ± 34 MPa, 1833 ± 45 MPa, and 448 ± 25 Hv, respectively. Heat treatment decreases the hardness values to 419 ± 26 Hv. The maximum compressive stress of the alloy increased to 2123 + 41 MPa while yield strength decreased to 1095 ± 45 with the treatment.

scholarly journals Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 345 ◽  
Author(s):  
Lianzan Yang ◽  
Yongyan Li ◽  
Zhifeng Wang ◽  
Weimin Zhao ◽  
Chunling Qin
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
High Specific Surface Area ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

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