Refining As-Cast Structures of Novel SixTiVCrZr High-Entropy Alloys Using Estimated Effective Solidification Temperature Obtained Using Chvorinov’s Rule

High-entropy alloys (HEAs), i.e., multicomponent alloys where (typically five or more) elements are combined in equal, or roughly equal, quantities, are of great current interest, due to their formation of single, simple structured phases, and the unusual properties they can potentially exhibit. Phase presence may be predicted using semi-empirical methods, but deviations from predictions may be seen during the course of alloy synthesis, with the formation of unexpected phases. The generation of such phases may be controlled with knowledge of the effective solidification temperature; in this full article, Chvorinov’s rule for solidification time is used to estimate this temperature as part of the design of a new multiphase alloy system, TiVCrZr-Six. Further heat treatment of the TiVCrZr-Si system confirms the applicability of this approach. The new compositions demonstrate mechanical properties that suggest potential for optimization for high-temperature applications.

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From High-Manganese Steels to Advanced High-Entropy Alloys

Metals ◽

10.3390/met9070726 ◽

2019 ◽

Vol 9 (7) ◽

pp. 726 ◽

Cited By ~ 4

Author(s):

Christian Haase ◽

Luis Antonio Barrales-Mora

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Structural Material ◽

High Entropy Alloys ◽

High Manganese ◽

High Entropy ◽

Design Concepts ◽

Physical Mechanisms ◽

High Manganese Steels ◽

Manganese Steels

Arguably, steels are the most important structural material, even to this day. Numerous design concepts have been developed to create and/or tailor new steels suited to the most varied applications. High-manganese steels (HMnS) stand out for their excellent mechanical properties and their capacity to make use of a variety of physical mechanisms to tailor their microstructure, and thus their properties. With this in mind, in this contribution, we explore the possibility of extending the alloy design concepts that haven been used successfully in HMnS to the recently introduced high-entropy alloys (HEA). To this aim, one HMnS steel and the classical HEA Cantor alloy were subjected to cold rolling and heat treatment. The evolution of the microstructure and texture during the processing of the alloys and the resulting properties were characterized and studied. Based on these results, the physical mechanisms active in the investigated HMnS and HEA were identified and discussed. The results evidenced a substantial transferability of the design concepts and more importantly, they hint at a larger potential for microstructure and property tailoring in the HEA.

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Effect of Heat Treatment and Titanium Addition on the Microstructure and Mechanical Properties of Cast Fe31Mn28 Ni15Al24.5Tix High-Entropy Alloys

Advances in Materials Science and Engineering ◽

10.1155/2019/2157592 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Shimaa El-Hadad ◽

Mervat Ibrahim ◽

Mohamed Mourad

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Treatment Time ◽

Low Cost ◽

High Hardness ◽

Lamellar Spacing ◽

High Entropy Alloys ◽

Titanium Addition ◽

High Entropy ◽

Ti Content

High-entropy alloys (HEAs) are multiprincipal element alloys with controllable properties. Studying the mechanical properties of these alloys and relating them to their microstructures is of interest. In the current investigation, Fe31Mn28 Ni15Al24.5Tix high-entropy alloys with Ti content (0–3 wt.%) were prepared by casting in an induction furnace. Different heat treatments were applied, and the microstructure and hardness of the cast samples were studied. It was observed that addition of up to 3.0 wt.% Ti significantly increases the hardness of the alloy from 300 to 500 (Hv) by the combined effect of solid solution strengthening and via decreasing lamellar spacing. Heat treatment at 900°C for 10 h enhanced the hardness at lower Ti percentages (0.0–0.8 wt.%) by decreasing the lamellar spacing, while no change was observed at higher Ti content. It was also observed that extending the treatment time to 20 h affected negatively the hardness of the alloy. Concluding, HEAs can achieve high hardness using low-cost principle elements with minor alloying additives compared to the other traditional alloys.

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Microstructural Characterization and Mechanical Properties of Laser Deposited High Entropy Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2370 ◽

2014 ◽

Vol 783-786 ◽

pp. 2370-2375

Author(s):

Harihar Sistla ◽

Joseph W. Newkirk ◽

F. Frank Liou

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Microstructural Characterization ◽

Alloy System ◽

Lattice Parameter ◽

Laser Deposition ◽

Advanced Materials ◽

Mechanical And Thermal Properties ◽

High Entropy Alloys ◽

High Entropy

High entropy alloys have attracted great interest due to their flexibility in composition accompanied with very interesting properties, which make these materials candidates for further research. The formation of single solid solution phases as a preference to complex mixtures of intermetallic phases leads to good mechanical and thermal properties. Additive manufacturing in the form of Laser deposition presents us with a very unique way to manufacture near net shape metallic components with advanced materials. The present study focusses on the characterization of High entropy alloys manufactured through laser deposition. The alloy system considered for this study is (AlFeCoCrNi). The ratio of aluminum to nickel was decreased to observe the transition of the solid solution from a BCC structure to a FCC structure. The lattice parameter increased from .288 nm to .357 nm and the hardness decreased from Hv 670 to Hv 149 respectively. The effect of composition on thermodynamic variables, microstructure and mechanical properties were analyzed.

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Tailoring Microstructures and Mechanical Properties of AlCoCrFeNiTi0.3 High-Entropy Alloys by Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.745-746.768 ◽

2013 ◽

Vol 745-746 ◽

pp. 768-774 ◽

Cited By ~ 3

Author(s):

Jun Wei Qiao ◽

Y.F. Wang ◽

R.Q. Wang ◽

J.Y. Shi ◽

S.B. Sang ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Volume Fraction ◽

Treatment Temperature ◽

High Entropy Alloys ◽

Static Compression ◽

High Entropy ◽

Bcc Structure ◽

Microstructures And Mechanical Properties ◽

Quasi Static Compression

The microstructures and mechanical properties of AlCoCrFeNi0.3 high-entropy alloys (HEAs) are tailored through heat treatment. During heat treatment, the dendrite phase with a body-centered-cubic (bcc) structure transformed into the interdendrite phase with a bcc structure. Due to the element accumulation with higher hardness in the interdendrites and the increase of volume fraction of interdendrites, the average hardness of AlCoCrFeNi0.3 HEAs increased with the heat-treatment temperature, and the highest hardness was 625 HV. After 500 heat treatment, the optimized mechanical properties under quasi-static compression were achieved, and the yielding strength and fracture plasticity were 2.30 GPa and 9 %, respectively. Upon dynamic loading, the mechanical properties of HEAs were greatly enhanced.

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Transition from High-Entropy to Conventional Alloys: Which Are Better?

Materials ◽

10.3390/ma14195824 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5824

Author(s):

Emil Babić ◽

Đuro Drobac ◽

Ignacio Alejandro Figueroa ◽

Mathilde Laurent-Brocq ◽

Željko Marohnić ◽

...

Keyword(s):

Mechanical Properties ◽

Electronic Structure ◽

Specific Heat ◽

Atomic Structure ◽

Alloy System ◽

Photoemission Spectroscopy ◽

High Entropy Alloys ◽

Iron Group ◽

High Entropy ◽

Alloy Systems

The study of the transition from high-entropy alloys (HEAs) to conventional alloys (CAs) composed of the same alloying components is apparently important, both for understanding the formation of HEAs and for proper evaluation of their potential with respect to that of the corresponding CAs. However, this transition has thus far been studied in only two types of alloy systems: crystalline alloys of iron group metals (such as the Cantor alloy and its derivatives) and both amorphous (a-) and crystalline alloys, TE-TL, of early (TE = Ti, Zr, Nb, Hf) and late (TL = Co, Ni, Cu) transition metals. Here, we briefly overview the main results for the transition from HEAs to CAs in these alloy systems and then present new results for the electronic structure (ES), studied with photoemission spectroscopy and specific heat, atomic structure, thermal, magnetic and mechanical properties of a-TE-TL and Cantor-type alloys. A change in the properties of the alloys studied on crossing from the HEA to the CA concentration range mirrors that in the ES. The compositions of the alloys having the best properties depend on the alloy system and the property selected. This emphasizes the importance of knowing the ES for the design of new compositional complex alloys with the desired properties.

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Effect of Heat Treatment on the Phase Composition, Microstructure and Mechanical Properties of Al0.6CrFeCoNi and Al0.6CrFeCoNiSi0.3 High-Entropy Alloys

Metals ◽

10.3390/met8110974 ◽

2018 ◽

Vol 8 (11) ◽

pp. 974 ◽

Cited By ~ 1

Author(s):

Lijia Chen ◽

Kirsten Bobzin ◽

Zheng Zhou ◽

Lidong Zhao ◽

Mehmet Öte ◽

...

Keyword(s):

Mechanical Properties ◽

Phase Transition ◽

Heat Treatment ◽

Phase Composition ◽

Elevated Temperatures ◽

Intermetallic Phase ◽

Phase Changes ◽

High Entropy Alloys ◽

High Entropy ◽

Heat Treated

High-entropy alloys exhibit some interesting mechanical properties including an excellent resistance against softening at elevated temperatures. This gives high-entropy alloys (HEAs) great potential as new structural materials for high-temperature applications. In a previous study of the authors, oxidation behavior of Al0.6CrFeCoNi and Al0.6CrFeCoNiSi0.3 high-entropy alloys at T = 800 °C, 900 °C and 1000 °C was investigated. Si-alloying was found to increase the oxidation resistance by promoting the formation of a continuous Al2O3 layer, avoiding the formation of AlN at T = 800 °C. Obvious phase changes were identified in the surface areas of both alloys after the oxidation experiments. However, the effects of heat treatment and Si-alloying on the phase transition in the bulk were not investigated yet. In this study, Al0.6CrFeCoNi and Al0.6CrFeCoNiSi0.3 high-entropy alloys were heat-treated at T = 800 °C and T = 1000 °C to investigate the effect of heat treatment on microstructure, phase composition and mechanical properties of both alloys. The results show that alloying Al0.6CrFeCoNi with Si caused a phase transition from dual phases consisting of BCC and FCC to a single BCC phase in an as-cast condition. Furthermore, increased hardness for as-cast and heat-treated samples compared with the Al0.6CrFeCoNi alloy was observed. In addition, the heat treatment facilitated the phase transition and the precipitation of the intermetallic phase, which resulted in the change of the mechanical properties of the alloys.

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