Influence of compressive strain on the microstructural evolution of an AlCoCrFeNi high entropy alloy

Lee, Kwang Seok; Kang, Joo-Hee; Na, Young Sang

doi:10.1016/j.matchar.2017.08.010

Cited by 39 publications

(13 citation statements)

References 25 publications

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“…The deviation of the shape factor from 1 (circle) is caused by the highly anisotropic microstructure of the compression specimens containing several columnar grains oriented in [100] crystallographic direction parallel or nearly parallel to the load axis. The plastic deformation of fcc HEAs is controlled by a planar glide of dislocations on close-packed {111} planes and along the close-packed 110 directions at high temperatures [30][31][32]. Since the active {111} 110 slip systems are oriented randomly to the load axis due to a random angular rotation of [001] crystallographic direction of the individual columnar grains, the nonuniform deformation leads to an asymmetric shape of the barrelled region.…”

Section: Non-uniform Deformation Of Compression Specimensmentioning

confidence: 99%

Effect of anisotropic microstructure on high-temperature compression deformation of CoCrFeNi based complex concentrated alloy

Stamborska¹,

Lapin²

2018

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The effect of anisotropic as-cast microstructure on high-temperature compression deformation of multiphase Co24Cr19Fe24Ni19Al8(Ti,Si,C)6 (at.%) complex concentrated alloy (CCA) derived from a single phase CoCrFeNi based high entropy alloy (HEA) was studied at temperatures ranging from 750 to 900 • C. The highly anisotropic microstructure composed of several columnar grains with [100] crystallographic direction parallel or nearly parallel to the load axis leads to asymmetric barrelled shapes of the compression specimens with multiple protuberances on the barrelled surfaces. The experimental barrelled shapes differ from the numerically calculated ones. The deformation curves exhibit strain hardening stage which is followed by a deformation at a constant flow stress at all studied temperatures. The work hardening rate (WHR) first increases with increasing strain. After achieving a peak value, the WHR decreases and achieves values around zero corresponding to the steady-state deformation. The finite element analysis (FEA) of 3D distribution of local equivalent strains and stresses corresponds qualitatively quite well to the observed structural changes within the barrelled specimens. K e y w o r d s : complex concentrated alloys, high-entropy alloys, anisotropy, plastic deformation, mechanical properties, finite element modelling

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Section: Non-uniform Deformation Of Compression Specimensmentioning

confidence: 99%

Effect of anisotropic microstructure on high-temperature compression deformation of CoCrFeNi based complex concentrated alloy

Stamborska¹,

Lapin²

2018

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“…Besides, samples #3, #4, #6 and #7 also have a small peak at the position of 82.3° representing the bcc-structure FeCoNiCrAl phase with a (211) plane. The XRD results illustrate that all the film samples have a preferred orientation of [110] with single bcc structure, which is different from the FeCoNiCrAl high entropy alloys prepared by other methods having mixed phase structures [26,27]. To further examine the average grain size of axial columnar crystal, the full width at half maximum (FWHM) of the main peak is given in Table 2, and the average grain size is calculated using Scherrer formula D = K·λ/B·cosθ where the Scherrer constant K = 0.89, wavelength λ = 0.154 nm and B = FWHM.…”

Section: Resultsmentioning

confidence: 99%

Growth Mechanisms and the Effects of Deposition Parameters on the Structure and Properties of High Entropy Film by Magnetron Sputtering

Liang

Wang

et al. 2019

Materials

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Despite intense research on high entropy films, the mechanism of film growth and the influence of key factors remain incompletely understood. In this study, high entropy films consisting of five elements (FeCoNiCrAl) with columnar and nanometer-scale grains were prepared by magnetron sputtering. The high entropy film growth mechanism, including the formation of the amorphous domain, equiaxial nanocrystalline structure and columnar crystal was clarified by analyzing the microstructure in detail. Besides, the impacts of the important deposition parameters including the substrate temperature, the powder loaded in the target, and the crystal orientation of the substrate on the grain size and morphology, phase structure, crystallinity and elemental uniformity were revealed. The mechanical properties of high entropy films with various microstructure features were investigated by nanoindentation. With the optimized grain size and microstructure, the film deposited at 350 °C using a power of 100 W exhibits the highest hardness of 11.09 GPa. Our findings not only help understanding the mechanisms during the high entropy film deposition, but also provide guidance in manufacturing other novel high entropy films.

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“…Moreover, because of the excellent compressive properties of the AlCoCrFeNi alloy, including a yield stress of 1251 MPa, a compressive stress of 2004 MPa, and a fracture strain of 32.7%, it demonstrates immense potential for development into structural materials [15]. In addition, the multi-phase refining of the suction-cast AlCoCr-FeNi alloy was proposed as a promising structural material with considerable ductility without the considerable expense of strength by feasible thermomechanical processing [16]. The wear rate of the AlCoCrFeNi alloy is low under high load because of the high hardness of the B2 matrix, indicative of good wear resistance for this alloy and the possibility of developing a wear-resistant material [17].…”

Section: Introductionmentioning

confidence: 99%

Effects of the Replacement of Co with Ni on the Microstructure, Mechanical Properties, and Age Hardening of AlCo1−xCrFeNi1+x High-Entropy Alloys

Lee

Shun

2021

Materials

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In this study, effects of the replacement of Co with Ni on the microstructure, mechanical properties, and age hardening of high-entropy alloys of AlCo1−xCrFeNi1+x (x = molar ratio; x = 0, 0.5, 1, denoted as X0, X0.5, and X1, respectively) were investigated. These three alloys exhibited a dendritic structure comprising an ordered BCC matrix, a BCC phase, and an FCC or an ordered FCC phase. From X0 to X1 alloys, the yield stress and compressive stress decreased from 1202 and 1790 MPa to 693 and 1537 MPa, respectively. However, fracture strain increased from 0.15 to 0.42. Peak age hardening at 600 °C for the X0 alloy was due to the precipitation of the (Cr,Fe)-rich σ phase. Peak age hardening for the X0.5 and X1 alloys was observed at 500 °C because of the precipitation of the σ phase and BCC phase, respectively.

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Influence of compressive strain on the microstructural evolution of an AlCoCrFeNi high entropy alloy

Cited by 39 publications

References 25 publications

Effect of anisotropic microstructure on high-temperature compression deformation of CoCrFeNi based complex concentrated alloy

Effect of anisotropic microstructure on high-temperature compression deformation of CoCrFeNi based complex concentrated alloy

Growth Mechanisms and the Effects of Deposition Parameters on the Structure and Properties of High Entropy Film by Magnetron Sputtering

Effects of the Replacement of Co with Ni on the Microstructure, Mechanical Properties, and Age Hardening of AlCo1−xCrFeNi1+x High-Entropy Alloys

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