Microstructural design by severe warm-rolling for tuning mechanical properties of AlCoCrFeNi2.1 eutectic high entropy alloy

Reddy, S. R.; Sunkari, U.; Łozinko, Adrianna; Saha, Rajib; Guo, Sheng; Bhattacharjee, P.P.

doi:10.1016/j.intermet.2019.106601

Cited by 33 publications

(16 citation statements)

References 44 publications

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“…These ingots were thicker than those used in Refs. [24][25][26][27], which resulted in a slower cooling rate and in a different as-cast microstructure compared to that in the ingots used in the previous studies. For example, the lamella widths (thicknesses) measured in our ingots [29] were larger than those reported in Refs.…”

Section: Methodsmentioning

confidence: 83%

“…For example, the lamella widths (thicknesses) measured in our ingots [29] were larger than those reported in Refs. [24][25][26][27].…”

Section: Methodsmentioning

confidence: 99%

“…As these annealing experiments involved only isochronal (1 h) annealing at different temperatures, the recrystallization kinetics were not considered in Refs. [24][25][26][27][28]. Furthermore, the evolution of mechanical properties during the course of static recrystallization was not analyzed in these previous reports.…”

Section: Introductionmentioning

confidence: 98%

“…Attempts to further improve mechanical properties of the as-cast AlCoCrFeNi 2.1 alloy were made using either warm, cold or cryo-rolling with subsequent annealing. It was shown that heavy rolling at 750 • C, as well as recrystallization annealing of heavily cold-or cryo-rolled samples, resulted in improved combinations of strength and ductility in this alloy [24][25][26][27][28]. As these annealing experiments involved only isochronal (1 h) annealing at different temperatures, the recrystallization kinetics were not considered in Refs.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evolution of microstructure and mechanical properties during annealing of heavily rolled AlCoCrFeNi2.1 eutectic high-entropy alloy

Łozinko

Gholizadeh

Zhang

et al. 2022

Materials Science and Engineering: A

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Section: Methodsmentioning

confidence: 83%

“…For example, the lamella widths (thicknesses) measured in our ingots [29] were larger than those reported in Refs. [24][25][26][27].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evolution of microstructure and mechanical properties during annealing of heavily rolled AlCoCrFeNi2.1 eutectic high-entropy alloy

Łozinko

Gholizadeh

Zhang

et al. 2022

Materials Science and Engineering: A

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“…A further increase in the B2 fraction was also observed in the EHEA when warm-rolled up to 90 pct reduction at 750°C [28] and also during subsequent annealing of the EHEA at 800°C after warm-rolling. [29] These phase transformations during warm-rolling were related to the structural features of the deformed materials including high energy interfaces and dislocations, which can effectively reduce the activation barrier to heterogeneous nucleation, thus accelerating phase transformations and decomposition. Such dynamic precipitation may significantly affect the operating dynamic softening mechanism during deformation resulting in unexpected changes in microstructure evolution.…”

Section: Introductionmentioning

confidence: 99%

Influence of Process Parameters on Microstructure Evolution During Hot Deformation of a Eutectic High-Entropy Alloy (EHEA)

Ahmed

Chadha

Reddy

et al. 2020

Metall Mater Trans A

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High-entropy alloys (HEAs) have shown unique combinations of strength and ductility along with other properties after optimized thermomechanical processing (TMP). In this study, the hot deformation of an AlCoCrFeNi 2.1 eutectic high-entropy alloy (EHEA) was studied by using a Gleeble 3800 Ò thermomechanical simulator at 800°C, 1000°C and 1200°C deformation temperature under different strain rates of 10 À4 , 10 À2 , and 1 s À1. The influence of strain rate and temperature on the evolution of the microstructure was discussed. The apparent activation energy (Q), stress exponent (n) and Zener-Holloman parameter (Z) were determined from the true stress-strain curves to develop the constitutive equation. The activation energy was determined to be 336 kJ/mol, and the stress exponent (n) was 2.5. Microstructures, characterized using electron-backscattered diffraction (EBSD), were analyzed as a function of (Z) values and interpreted in terms of solute diffusion and the interactions between dynamic softening (dynamic recovery and dynamic recrystallization) and hardening (dynamic precipitation) phenomena. It was found that the hot deformation behavior of EHEAs was controlled by pipe diffusion for the selected process parameters. The pipe diffusion coefficient of Ni increased with increasing strain rate at constant deformation temperature, whereas the lattice diffusion coefficient remained constant for all the examined strain rates. Dynamic recovery (DRV) was the dominant softening mechanism at lower temperatures irrespective of strain rates, while dynamic precipitation played a critical role in the inhibition of dynamic recrystallization (DRX) under these conditions. At higher temperatures and for all the strain rates, microstructure evolution was controlled by the DRX mechanism.

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Strong‐Yet‐Ductile Eutectic Alloys Employing Cocoon‐Like Nanometer‐Sized Dislocation Cells

Shi,

Li,

Jiang

et al. 2024

Advanced Materials

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Eutectic alloys (EAs) with superior fluidity are known to be the easiest to cast into high‐quality ingots, making them the alloys of choice for making large‐sized structural parts. However, conventional EAs (CEAs) have never reached strength–ductility combinations on par with the best in other alloy categories. Via thermomechanical processing of cast Ni‐32.88wt%Fe‐9.53wt%Al CEAs, a cocoon‐like nano‐meshed (as fine as 26 nm) network of dislocations (CNN‐D) is produced via recovery annealing, through the rearrangement of cold‐work‐accumulated dislocations anchored by dense pre‐existing nanoprecipitates. In lieu of traditional plasticity mechanisms, such as TWIP and TRIP, the CNN‐D is particularly effective in eutectic lamellae with alternating phases, as it instigates nanometer‐spaced planar slip bands that not only dynamically refine the microstructure but also transmit from the FCC (face‐centered‐cubic) layers into the otherwise brittle B2 layers. These additional mechanisms for strengthening and strain hardening sustain stable tensile flow, resulting in a striking elevation of both strength and ductility to outrank not only all previous CEAs, but also the state of the art—additively manufactured eutectic high‐entropy alloys. The CNN‐D thus adds a novel microstructural strategy for performance enhancement, especially for compositionally complex alloys that increasingly make use of nanoprecipitates or local chemical order.

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Microstructural design by severe warm-rolling for tuning mechanical properties of AlCoCrFeNi2.1 eutectic high entropy alloy

Cited by 33 publications

References 44 publications

Evolution of microstructure and mechanical properties during annealing of heavily rolled AlCoCrFeNi2.1 eutectic high-entropy alloy

Evolution of microstructure and mechanical properties during annealing of heavily rolled AlCoCrFeNi2.1 eutectic high-entropy alloy

Influence of Process Parameters on Microstructure Evolution During Hot Deformation of a Eutectic High-Entropy Alloy (EHEA)

Strong‐Yet‐Ductile Eutectic Alloys Employing Cocoon‐Like Nanometer‐Sized Dislocation Cells

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