Microstructure and Mechanical Properties of Equitomic CoCrFeCuNi High Entropy Alloy

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.

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Microstructure and Mechanical Properties of Equiatomic CrMnCoNiCu High Entropy Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.909.39 ◽

2017 ◽

Vol 909 ◽

pp. 39-43 ◽

Cited By ~ 1

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.

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

Advances in Materials Science and Engineering ◽

10.1155/2017/1950196 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6 ◽

Cited By ~ 2

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.

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