Microstructures and mechanical properties of FeCoCrNi high entropy alloy/WC reinforcing particles composite coatings prepared by laser cladding and plasma cladding

Author(s):  
Y.B. Peng ◽  
W. Zhang ◽  
T.C. Li ◽  
M.Y. Zhang ◽  
L. Wang ◽  
...  
Entropy ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 75 ◽  
Author(s):  
Jingrui Niu ◽  
Wei Li ◽  
Ping Liu ◽  
Ke Zhang ◽  
Fengcang Ma ◽  
...  

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.


Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1539
Author(s):  
Yu-Hsuan Liang ◽  
Chia-Lin Li ◽  
Chun-Hway Hsueh

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.


2021 ◽  
pp. 1-22
Author(s):  
Xinhong Wang ◽  
S. S. Liu ◽  
G. L. Zhao ◽  
M. Zhang

Abstract In-situ TiN ceramic particle reinforced FeCoNiCrMnTi high entropy alloy coating was fabricated by laser cladding processing at high purity nitrogen gas atmosphere on the AISI 304 stainless steel substrate. The effect of Ti addition on the microstructure, phase structure and wear properties of the coatings were investigated. The results showed that phase structure of the coatings were mainly FCC-type γ phase. A few of cubic or flower-like TiN ceramic were formed after adding titanium into the FeCoNiCrMn powder. When atomic ratio of Ti exceeds 0.5, Laves phases appeared in the coatings. With increasing of Ti, the micro-hardness and wear resistance of the coatings increased, but friction coefficient and crack resistance of the coatings reduced. Suitable Ti content in the FeCoNiCrMnTix, laser composite coating had higher resistance to adhesive wear, oxidation wear and cracking resistance.


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