Modifications of microstructures and mechanical properties of CoCrFeMnNi high entropy alloy films by adding Ti element

2020 ◽  
Vol 399 ◽  
pp. 126149
Author(s):  
Ya-Chu Hsu ◽  
Chia-Lin Li ◽  
Chun-Hway Hsueh
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloy ◽  
Alloy Films ◽  
High Entropy ◽  
Microstructures And Mechanical Properties

scholarly journals Effects of Nb Addition on Microstructures and Mechanical Properties of Nbx-CoCrFeMnNi High Entropy Alloy Films

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1539
Author(s):  
Yu-Hsuan Liang ◽  
Chia-Lin Li ◽  
Chun-Hway Hsueh
Keyword(s):  
Mechanical Properties ◽  
Amorphous Phase ◽  
Compressive Yield Strength ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Compression Tests ◽  
Alloy Films ◽  
High Entropy ◽  
Microstructures And Mechanical Properties ◽  
Nb Addition

In the present work, Nbx-CoCrFeMnNi high entropy alloy films (HEAFs, 0 to 7.2 at.% Nb) were fabricated by radio frequency (RF) magnetron co-sputtering of CoCrFeMnNi alloy and Nb targets. The effects of Nb addition on the microstructures and mechanical properties of HEAFs were systematically investigated. For Nb-free film (0 at.% Nb), the face-centered cubic (FCC) peaks were identified in the X-ray diffraction (XRD) pattern. The addition of Nb resulted in a broadening of diffraction peaks, a decrease in peak intensity, and the vanishment of high-angle peaks. Transmission electron microscope (TEM) images indicated the formation of nanotwins at low Nb concentrations, and a transition from a single phase FCC solid solution to an amorphous phase was observed with the increasing Nb concentration. The films were strengthened with an increase in Nb concentration. Specifically, the hardness characterized by nanoindentation increased from 6.5 to 8.1 GPa. The compressive yield strength and fracture strength measured from micropillar compression tests were improved from 1.08 GPs and 2.56 GPa to 2.70 GPa and 5.76 GPa, respectively, whereas the fracture strain decreased from >29.4% (no fracture) to 15.8%. Additionally, shear banding was observed in the presence of amorphous phase.

Microstructures and mechanical properties of CoCrFeMnNiV high entropy alloy films

2020 ◽  
Vol 820 ◽  
pp. 153388 ◽  
Author(s):  
Shuang Fang ◽  
Cheng Wang ◽  
Chia-Lin Li ◽  
Jun-Hua Luan ◽  
Zeng-Bao Jiao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Entropy Alloy ◽  
Alloy Films ◽  
High Entropy ◽  
Microstructures And Mechanical Properties

scholarly journals Effects of Al Addition on Microstructures and Mechanical Properties of CoCrFeMnNiAlx High Entropy Alloy Films

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 2 ◽  
Author(s):  
Ya-Chu Hsu ◽  
Chia-Lin Li ◽  
Chun-Hway Hsueh
Keyword(s):  
Mechanical Properties ◽  
Compressive Yield Strength ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Alloy Films ◽  
High Entropy ◽  
Al Content ◽  
Microstructures And Mechanical Properties ◽  
Fcc Phase ◽  
Bcc Phase

CoCrFeMnNiAlx (x = 0, 0.07, 0.3, 0.6, 1.0, 1.3) high-entropy alloy films (HEAFs) were processed by co-sputtering of CoCrFeMnNi alloy and Al targets. The effects of Al content on the microstructures and mechanical properties of HEAFs were studied. The XRD results indicated that the crystalline structure changed from the single face-centered cubic (FCC) phase for x = 0 and 0.07 to duplex FCC + body-centered cubic (BCC) phases for x = 0.3 and 0.6, and eventually, to a single BCC phase for x = 1.0 and 1.3, which agreed with the corresponding selected-area electron diffraction patterns. Also, nanotwins were observed in the FCC phase. Mechanical properties of films were studied using nanoindentation and micropillar compression tests. The hardness increased from 5.71 GPa at x = 0 to 8.74 GPa at x = 1.3. The compressive yield strength increased from 1.59 GPa to 3.73 GPa; however, the fracture strain decreased from 20.91% (no fracture) to 13.78% with the increasing Al content. Both nanotwins and BCC phase contributed to the strengthening effects for CoCrFeMnNiAlx HEAFs. Also, compared to the bulk CoCrFeMnNiAlx counterpart, the film exhibited much higher hardness and strength because of the much smaller grain size and the presence of nanotwins.

scholarly journals Effects of Silicon Content on the Microstructures and Mechanical Properties of (AlCrTiZrV)-Six-N High-Entropy Alloy Films

Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 75 ◽  
Author(s):  
Jingrui Niu ◽  
Wei Li ◽  
Ping Liu ◽  
Ke Zhang ◽  
Fengcang Ma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Amorphous Phase ◽  
Silicon Content ◽  
High Entropy Alloy ◽  
Strengthening Effect ◽  
Nanocomposite Structure ◽  
High Entropy ◽  
Nanocrystalline Structures ◽  
Microstructures And Mechanical Properties

A series of (AlCrTiZrV)-Six-N films with different silicon contents were deposited on monocrystalline silicon substrates by direct-current (DC) magnetron sputtering. The films were characterized by the X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and nano-indentation techniques. The effects of the silicon content on the microstructures and mechanical properties of the films were investigated. The experimental results show that the (AlCrTiZrV)N films grow in columnar grains and present a (200) preferential growth orientation. The addition of the silicon element leads to the disappearance of the (200) peak, and the grain refinement of the (AlCrTiZrV)-Six-N films. Meanwhile, the reticular amorphous phase is formed, thus developing the nanocomposite structure with the nanocrystalline structures encapsulated by the amorphous phase. With the increase of the silicon content, the mechanical properties first increase and then decrease. The maximal hardness and modulus of the film reach 34.3 GPa and 301.5 GPa, respectively, with the silicon content (x) of 8% (volume percent). The strengthening effect of the (AlCrTiZrV)-Six-N film can be mainly attributed to the formation of the nanocomposite structure.

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