scholarly journals Alloy Designs of High-Entropy Crystalline and Bulk Glassy Alloys by Evaluating Mixing Enthalpy and Delta Parameter for Quinary to Decimal Equi-Atomic Alloys

2014 ◽  
Vol 55 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Akira Takeuchi ◽  
Kenji Amiya ◽  
Takeshi Wada ◽  
Kunio Yubuta ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Mixing Enthalpy ◽  
High Entropy ◽  
Glassy Alloys

A new strategy to design eutectic high-entropy alloys using mixing enthalpy

2017 ◽  
Vol 91 ◽  
pp. 124-128 ◽  
Author(s):  
Yiping Lu ◽  
Hui Jiang ◽  
Sheng Guo ◽  
Tongmin Wang ◽  
Zhiqiang Cao ◽  
...  
Keyword(s):  
Mixing Enthalpy ◽  
High Entropy Alloys ◽  
High Entropy ◽  
New Strategy

scholarly journals Compositional Dependence of Phase Selection in CoCrCu0.1FeMoNi-Based High-Entropy Alloys

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1290 ◽  
Author(s):  
Ning Liu ◽  
Chen Chen ◽  
Isaac Chang ◽  
Pengjie Zhou ◽  
Xiaojing Wang
Keyword(s):  
Molar Ratio ◽  
Mixing Enthalpy ◽  
High Entropy Alloy ◽  
Valence Electron Concentration ◽  
Face Centered Cubic ◽  
Distortion Parameter ◽  
Local Lattice Distortion ◽  
Phase Selection ◽  
High Entropy ◽  
Fcc Structure

To study the effect of alloy composition on phase selection in the CoCrCu0.1FeMoNi high-entropy alloy (HEA), Mo was partially replaced by Co, Cr, Fe, and Ni. The microstructures and phase selection behaviors of the CoCrCu0.1FeMoNi HEA system were investigated. Dendritic, inter-dendritic, and eutectic microstructures were observed in the as-solidified HEAs. A simple face centered cubic (FCC) single-phase solid solution was obtained when the molar ratio of Fe, Co, and Ni was increased to 1.7 at the expense of Mo, indicating that Fe, Co, and Ni stabilized the FCC structure. The FCC structure was favored at the atomic radius ratio δ ≤ 2.8, valence electron concentration (VEC) ≥ 8.27, mixing entropy ΔS ≤ 13.037, local lattice distortion parameter α2 ≤ 0.0051, and ΔS/δ2 > 1.7. Mixed FCC + body centered cubic (BCC) structures occurred for 4.1 ≤ δ ≤ 4.3 and 7.71 ≤ VEC ≤ 7.86; FCC or/and BCC + intermetallic (IM) mixtures were favored at 2.8 ≤ δ ≤ 4.1 or δ > 4.3 and 7.39 < VEC ≤ 8.27. The IM phase is favored at electronegativity differences greater than 0.133. However, ΔS, α2, and ΔS/δ2 were inefficient in identifying the (FCC or/and BCC + IM)/(FCC + BCC) transition. Moreover, the mixing enthalpy cannot predict phase structures in this system.

scholarly journals Alloy Design for High-Entropy Bulk Glassy Alloys

2012 ◽  
Vol 36 ◽  
pp. 226-234 ◽  
Author(s):  
A. Takeuchi ◽  
N. Chen ◽  
T. Wada ◽  
W. Zhang ◽  
Y. Yokoyama ◽  
...  
Keyword(s):  
Alloy Design ◽  
High Entropy ◽  
Glassy Alloys

Microstructural Evolution and Hardness of CoxCrCuFeNi High-Entropy Alloys

2014 ◽  
Vol 789 ◽  
pp. 79-83 ◽  
Author(s):  
Xing Yan Gao ◽  
Ning Liu ◽  
Yun Xue Jin ◽  
Zhi Xuan Zhu
Keyword(s):  
Supersaturated Solid Solution ◽  
Xrd Analysis ◽  
Mixing Enthalpy ◽  
High Entropy Alloys ◽  
Micro Hardness ◽  
Hardness Testing ◽  
Cooling Process ◽  
High Entropy ◽  
Interdendritic Phase ◽  
Microstructure Characteristic

The effects of Co contents on the microstructure characteristic and phase structure of CoxCrCuFeNi high-entropy alloys were investigated by SEM, EDS and XRD. The microstructures consisted of dendrites and many nanoprecipitations in the interdendritic. Increase Co contents,the size of nanoprecipitated phase in the interdendritic firstly increased and then decreased slightly. According to XRD analysis, two simple FCC phases, dendrite phase and Cu-rich interdendritic phase were found. As a result of slow diffusion, supersaturated solid solution was formed during solidification and then nanophase was precipitated during the following cooling process. The results of EDS revealed that Fe、Co and Cr were rich in dendrites, while Cu was rich at the interdendritic. For element Ni, which was rich in dendrites when x≤1.0, but was almost the normal value in dendrites for x>1.0. The reason for segregation was related to the positive mixing enthalpy between elements. The contents of Co had little impact on the hardness of CoxCrCuFeNi high-entropy alloys according to micro-hardness testing.

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.

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