Effects of high pressure torsion on microstructures and properties of an Al0.1CoCrFeNi high-entropy alloy

Yu, Pengfei; Cheng, Honghui; Zhang, L.J.; Zhang, H.; Qin, Jing; Ma, Mingzhen; Liaw, Peter K.; Li, G.; Liu, R.P.

doi:10.1016/j.msea.2015.12.085

Cited by 112 publications

(25 citation statements)

References 56 publications

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“…6reveals the formation of new peaks marked with solid inverse triangles at 2θ ≈ 44.2 which correspond to the formation of a bcc phase with a lattice parameter of a ≈ 2.88 Å. This phase is consistent with the Cr-rich phase reported earlier in the CoCrFeNiMn HEA[9,10,19,20]. In addition, inFig.…”

supporting

confidence: 87%

“…The initial and HPT-processed microstructures in this HEA consist of a single fcc phase. It is well-known that the CoCrFeNiMn HEA is a precipitation-hardened alloy [19][20][21][22][23][24] note that precipitation is a diffusion-controlled phenomenon which will be significantly affected by the sluggish diffusion which is an inherent feature of conventional HEAs [30].…”

Section: The Phase Stability Of the Nanocrystalline Hea After Pdamentioning

confidence: 99%

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Effect of Ti on phase stability and strengthening mechanisms of a nanocrystalline CoCrFeMnNi high-entropy alloy

Shahmir

Nili‐Ahmadabadi

Shafiee

et al. 2018

Materials Science and Engineering: A

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A CoCrFeNiMnTi 0.1 high-entropy alloy (HEA) was processed by high-pressure torsion (HPT) followed by post-deformation annealing (PDA) at 200-900 °C. Microstructural evaluations revealed that the initial and HPT-processed microstructures consisted of a single fcc phase and there was no evidence for decomposition during severe plastic deformation. However, PDA at temperatures below 900 °C promoted the formation of a multi-phase microstructure containing new precipitates and significant grain coarsening occurred after PDA at >800 °C due to a dissolution of the precipitates. PDA at 800 °C for 60 min led to very good mechanical properties with an ultimate tensile strength (UTS) and elongation to failure of >1000 MPa and ~40%, respectively. The results demonstrate that the minor addition of Ti to the CoCrFeNiMn alloy has no direct effect on the strengthening mechanisms but nevertheless this addition significantly increases the thermal stability of the precipitates and these precipitates are effective in minimizing grain coarsening. Therefore, the Ti addition plays an important role in strengthening the HEA.

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supporting

confidence: 87%

Section: The Phase Stability Of the Nanocrystalline Hea After Pdamentioning

confidence: 99%

Effect of Ti on phase stability and strengthening mechanisms of a nanocrystalline CoCrFeMnNi high-entropy alloy

Shahmir

Nili‐Ahmadabadi

Shafiee

et al. 2018

Materials Science and Engineering: A

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“…There are only a few reports describing the influence of HPT processing on HEAs [16][17][18][19][20] but it was shown for the CoCrFeNiMn alloy that processing by HPT leads to exceptional grain refinement to ~10 nm with a significant strength of ~1.75 GPa, a hardness of ~4. 41 GPa and with a very low ductility of ~4% at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Evidence for superplasticity in a CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Shahmir

Liu

et al. 2017

Materials Science and Engineering: A

106

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A CoCrFeNiMn high-entropy alloy was processed by high-pressure torsion to produce a grain size of ~10 nm and then tested in tension at elevated temperatures from 773 to 1073 K using strain rates in the range from 1.0 × 10 -3 to 1.0 × 10 -1 s -1 . The alloy exhibited excellent ductility at these elevated temperatures including superplastic elongations with a maximum elongation of >600% at a testing temperature of 973 K. It is concluded that the formation of precipitates and the sluggish diffusion in the HEA inhibit grain growth and contribute to a reasonable stability of the fine-grained structure at elevated temperatures. The results show the activation energy for flow matches the anticipated value for grain boundary diffusion in nickel but the strain rate sensitivity is low due to the occurrence of some grain growth at these high testing temperatures.

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“…As shown in Figure 9, the plastic-deformation mechanism mainly includes dislocation slip and twinning. Yu et al showed that the plastic-deformation mechanisms of the single-phase fcc Al0.1CoCrFeNi HEA induced by HPT at room temperature [67]. The sample was prepared by arc-melting and then casted as a plate by vacuum induction.…”

Section: High-pressure Torsionmentioning

confidence: 99%

“…This gives us reason to assume that, unlike 300 K-HPT, low temperature HPT induces a phase transition of fcc-to-hcp [68]. Furthermore, the microstructure and thermal stability of the nanocrystalline CoCrFeMnNi HEA after HPT were reported, and the results indicated that the grain [67]. The sample was prepared by arc-melting and then casted as a plate by vacuum induction.…”

Section: High-pressure Torsionmentioning

confidence: 99%

Applications of High-Pressure Technology for High-Entropy Alloys: A Review

Dong

Zhou

Zhang

et al. 2019

Metals

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High-entropy alloys are a new type of material developed in recent years. It breaks the traditional alloy-design conventions and has many excellent properties. High-pressure treatment is an effective means to change the structures and properties of metal materials. The pressure can effectively vary the distance and interaction between molecules or atoms, so as to change the bonding mode, and form high-pressure phases. These new material states often have different structures and characteristics, compared to untreated metal materials. At present, high-pressure technology is an effective method to prepare alloys with unique properties, and there are many techniques that can achieve high pressures. The most commonly used methods include high-pressure torsion, large cavity presses and diamond-anvil-cell presses. The materials show many unique properties under high pressures which do not exist under normal conditions, providing a new approach for the in-depth study of materials. In this paper, high-pressure (HP) technologies applied to high-entropy alloys (HEAs) are reviewed, and some possible ways to develop good properties of HEAs using HP as fabrication are introduced. Moreover, the studies of HEAs under high pressures are summarized, in order to deepen the basic understanding of HEAs under high pressures, which provides the theoretical basis for the application of high-entropy alloys.Metals 2019, 9, 867 2 of 16 with the development of human civilization. However, due to the limitations of technical conditions, the application of pressure has just begun. High-pressure technology is a relatively-young and emerging discipline, but most of the condensed matter in the universe is under high pressure. The research on high pressures relies heavily on the experimental techniques, and each progression of the method has led to a significant expansion of our basic understanding of material behavior under high pressures.The progress in high-pressure experimental technology has directly promoted the development of the high-pressure science and provided an advanced method for frontier subjects. It has become an important field in modern scientific research. There are few studies on the structures of HEAs under high pressures. Interactions within the materials will change under high pressures and induce the generation of high-pressure phase transitions, thus becoming a new material with special properties. The materials will show many unique properties under high pressures, ones which do not exist under normal conditions, providing a subject for the in-depth study of materials. The behavior of HEAs under high pressures is a potential research direction for the future. High-Entropy Alloys (HEAs) ConceptHEAs are kinds of alloys developed in recent years. HEAs are loosely defined as solid-solution alloys that contain more than five principal elements in an equal or near-equal atomic percent (at. %) [4]. These kinds of alloys were defined by Yeh et al. [4] in 2004 as HEAs, and in the same year named by Cantor [5] et al. as the multi...

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Effects of high pressure torsion on microstructures and properties of an Al0.1CoCrFeNi high-entropy alloy

Cited by 112 publications

References 56 publications

Effect of Ti on phase stability and strengthening mechanisms of a nanocrystalline CoCrFeMnNi high-entropy alloy

Effect of Ti on phase stability and strengthening mechanisms of a nanocrystalline CoCrFeMnNi high-entropy alloy

Evidence for superplasticity in a CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Applications of High-Pressure Technology for High-Entropy Alloys: A Review

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