Microstructural Characterization and Mechanical Properties of Laser Deposited High Entropy Alloys

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.

Effect of Interstitial Elements on the Cryogenic Mechanical Behavior of FCC High Entropy Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1386-1391
Author(s):  
Anastasia Semenyuk ◽  
Margarita Klimova ◽  
Sergey Zherebtsov ◽  
Nikita Stepanov
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Thermomechanical Processing ◽  
Induction Melting ◽  
High Entropy Alloys ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
High Entropy ◽  
C And N ◽  
Interstitial Elements

High entropy alloys (HEAs) with face-centered cubic (fcc) structure, namely equiatomic CoCrFeMnNi alloy, have attracted considerable attention because of impressive cryogenic mechanical properties – strength, ductility, and fracture toughness. Further increase of the properties can be achieved, for example, by proper alloying. A particularly attractive option is the addition of interstitial elements like carbon or nitrogen. In present work, a series of CoCrFeMnNi-based alloys with different amounts of C and N (0-2 at.%) was prepared by induction melting. The alloys doped with C had lower Cr content to increase the solubility of carbon in the fcc solid solution. It was revealed that the solid solution strengthening effect of both C and N is significantly increased when the testing temperature decreases from 293K to 77K. The effect of thermomechanical processing on the structure and mechanical properties of the alloys is analyzed.

Microstructure and Mechanical Properties of FeNiCrCuAl High Entropy Alloys

2014 ◽  
Vol 1036 ◽  
pp. 101-105
Author(s):  
Gheorghe Buluc ◽  
Iulia Florea ◽  
Oana Bălţătescu ◽  
Costel Roman ◽  
Ioan Carcea
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Hardness ◽  
High Strength ◽  
High Entropy Alloys ◽  
Engineering Applications ◽  
High Entropy ◽  
Good Thermal Stability ◽  
Microstructure And Mechanical Properties ◽  
Wide Range

This paper presents the microstructure and the mechanical properties of FeNiCrCuAl high entropy alloys. The microstructure and mechanical properties of the annealed FeNiCrCuAl high entropy alloys were investigated using scanning electron microscopy, and X-ray diffraction. High entropy alloys have been known as a new type of materials and have been defined as having five or more principal elements, each one having a concentration between 5 and 35 at.%. Previous researches show that HEAs can be processed to form simple solid solution structures instead of intermetallics and other complicated compounds. This phenomenon is commonly attributed to the high configurational entropy in the solid solution state of HEAs. Furthermore, HEAs have also exhibited interesting properties such as high hardness and high strength, good thermal stability outstanding wear and oxidation resistance which offer great potential for engineering applications. The HEA systems explored in the past decade show that metallic elements are the most commonly used, e.g. Al, Cr, Fe, Co, Ni, Cu,Ti, etc. A wide range of HEAs exhibit high hardness, high strength, distinctive electrical and magnetic properties, high-temperature softening resistance, as well as favorable combination of compression strength and ductility. This combination of properties and the particular structures of HEAs are attractive for a number of potential engineering applications.

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

Materials ◽  
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.

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

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 317
Author(s):  
Zhaoyuan Leong ◽  
Yuhe Huang ◽  
Maximillian Bloomfield ◽  
Bethany Jim ◽  
George Kerridge ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Alloy System ◽  
High Entropy Alloys ◽  
Current Interest ◽  
Empirical Methods ◽  
Solidification Temperature ◽  
High Entropy ◽  
Multiphase Alloy ◽  
Semi Empirical

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.

scholarly journals Strengthening Mechanisms in CoCrFeNiX0.4 (Al, Nb, Ta) High Entropy Alloys Fabricated by Powder Plasma Arc Additive Manufacturing

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 721
Author(s):  
Yupeng Zhang ◽  
Qingkai Shen ◽  
Xizhang Chen ◽  
Subramanian Jayalakshmi ◽  
Ramachandra Arvind Singh ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Atomic Radius ◽  
Eutectic Structure ◽  
Precipitation Strengthening ◽  
High Entropy Alloys ◽  
Plasma Arc ◽  
High Entropy ◽  
Solid Solution Strengthening ◽  
Solution Strengthening

In high entropy alloys (HEAs), the addition of large-size atoms results in lattice distortion and further leads to solid solution strengthening or precipitation strengthening. However, the relationship between atomic radius, solid solution strengthening and precipitation strengthening has not been discerned yet. In this work, CoCrFeNiX0.4 (X = Al, Nb, Ta, with an equi-atomic radius) HEAs were prepared by powder plasma arc additive manufacturing (PPA-AM) and evaluated for their mechanical properties. Compression and nano-indentation hardness tests showed that the HEA with Ta showed the best properties. The influence of atomic radius and solid solubility on solid solution strengthening was investigated and the main strengthening mechanism that determines the mechanical properties of the developed HEAs was analyzed. The results showed that (i) the CoCrFeNiAl0.4 alloy did not show any solid solution strengthening effect and that a clear relation between solid solution strengthening and atomic size was not observed; (ii) in both CoCrFeNiTa0.4 and CoCrFeNiNb0.4 HEAs, precipitation strengthening and grain boundary strengthening effects are observed, wherein the difference in mechanical properties between both the alloys can be mainly attributed to the formation of fine eutectic structure in CoCrFeNiTa0.4; and (iii) from the microstructural analyses, it was identified that, in the CoCrFeNiTa0.4 HEA, the location containing a fine eutectic structure is accompanied by the formation of low-angle grain boundaries (LAGBs), which is also the region where deformed grains gather, giving rise to improved mechanical strengthening.

Designing High Entropy Alloys with Dual fcc and bcc Solid-Solution Phases: Structures and Mechanical Properties

2019 ◽  
Vol 50 (4) ◽  
pp. 1888-1901 ◽  
Author(s):  
Zhaowu Tang ◽  
Shang Zhang ◽  
Ruipeng Cai ◽  
Qing Zhou ◽  
Haifeng Wang
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
High Entropy Alloys ◽  
High Entropy
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