In Situ Laser Synthesis of High Entropy Alloy Coating on Ti-6Al-4V Alloy: Characterization of Microstructure and Properties

2017 ◽  
Vol 898 ◽  
pp. 643-650 ◽  
Author(s):  
Zhao Bing Cai ◽  
Xue Jia Pang ◽  
Xiu Fang Cui ◽  
Xin Wen ◽  
Zhe Liu ◽  
...  

In order to improve the surface properties of Ti-6Al-4V, high-entropy alloy coatings were prepared by in-situ laser cladding on the surface of Ti-6Al-4V substrate. The microstructure, micro-hardness, corrosion resistance and wear resistance were investigated. The results showed that the high-entropy alloy coating was composed of BCC high-entropy alloy phase, α-Ti phase and (Ni, Co)Ti2 phase. The micro-hardness of the high-entropy alloy coatings is much higher than that of Ti-6Al-4V substrate. The coating also has a better corrosion resistance than Ti-6Al-4V substrate, even superior to 304SS in 3.5wt.% NaCl solution at room temperature. Compared with Ti-6Al-4V substrate, the high-entropy alloy coating has a greater wear resistance with the wear mass loss decreased 28.2% and 23.1%, respectively. Wear patterns of Ti-6Al-4V substrate and high-entropy alloy coatings are the coexistence of adhesive wear and abrasive wear, but the wear degree of high-entropy alloy coatings is lower.

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 915 ◽  
Author(s):  
Kaijin Huang ◽  
Lin Chen ◽  
Xin Lin ◽  
Haisong Huang ◽  
Shihao Tang ◽  
...  

In order to improve the wear and corrosion resistance of an AZ91D magnesium alloy substrate, an Al0.5CoCrCuFeNi high-entropy alloy coating was successfully prepared on an AZ91D magnesium alloy surface by laser cladding using mixed elemental powders. Optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction were used to characterize the microstructure of the coating. The wear resistance and corrosion resistance of the coating were evaluated by dry sliding wear and potentiodynamic polarization curve test methods, respectively. The results show that the coating was composed of a simple FCC solid solution phase with a microhardness about 3.7 times higher than that of the AZ91D matrix and even higher than that of the same high-entropy alloy prepared by an arc melting method. The coating had better wear resistance than the AZ91D matrix, and the wear rate was about 2.5 times lower than that of the AZ91D matrix. Moreover, the main wear mechanisms of the coating and the AZ91D matrix were different. The former was abrasive wear and the latter was adhesive wear. The corrosion resistance of the coating was also better than that of the AZ91D matrix because the corrosion potential of the former was more positive and the corrosion current was smaller.


2019 ◽  
Vol 10 (1) ◽  
pp. 49 ◽  
Author(s):  
Dezheng Liu ◽  
Jing Zhao ◽  
Yan Li ◽  
Wenli Zhu ◽  
Liangxu Lin

The FeCoCrNiBx high-entropy alloy (HEA) coatings with three different boron (B) contents were synthesized on Q245R steel (American grade: SA515 Gr60) by laser cladding deposition technology. Effects of B content on the microstructure and wear properties of FeCoCrNiBx HEA coating were investigated. In this study, the phase composition, microstructure, micro-hardness, and wear resistance (rolling friction) were investigated by X-ray diffraction (XRD), a scanning electron microscope (SEM), a micro hardness tester, and a roller friction wear tester, respectively. The FeCoCrNiBx coatings exhibited a typical dendritic and interdendritic structure, and the microstructure was refined with the increase of B content. Additionally, the coatings were found to be a simple face-centered cubic (FCC) solid solution with borides. In terms of mechanical properties, the hardness and wear resistance ability of the coating can be enhanced with the increase of the B content, and the maximum hardness value of three HEA coatings reached around 1025 HV0.2, which is higher than the hardness of the substrate material. It is suggested that the present fabricated HEA coatings possess potentials in application of wear resistance structures for Q245R steel.


2019 ◽  
Vol 813 ◽  
pp. 159-164
Author(s):  
Carlos Alberto Souto ◽  
Gustavo Faria Melo da Silva ◽  
Laura Angelica Ardila Rodriguez ◽  
Aline C. de Oliveira ◽  
Kátia Regina Cardoso

Coatings with high entropy alloys of the AlCoCrFeNiV system were obtained by selective laser melting on low carbon steel substrates. The effect of the variation of the Fe and V contents as well as the laser processing parameters in the development of the coating were evaluated. The coatings were obtained from the simple powder mixtures of the high purity elemental components in a planetary ball mill. The coatings were obtained by using CO2 laser with a power of 100 W, diameter of 0.16 mm, and scan speed varying from 3 to 12 mm/s. Phase constituents, microstructure and hardness were investigated by XRD, SEM, and microhardness tester, respectively. Wear resistance measurements were carried out by the micro-abrasion method using ball-cratering tests. The coatings presented good adhesion to the substrate and high hardness, of the order of 480 to 650 HV. Most homogeneous coating with nominal composition was obtained by using the higher scan speed, 12 mm/s. Vanadium addition increased hardness and gave rise to a high entropy alloy coating composed by BCC solid solutions. Ball cratering tests conducted on HEA layer showing improvement of material wear resistance, when compared to base substrate, decreasing up to 88% its wear rate, from 1.91x10-6 mm3/Nmm to 0.23x10-6 mm3/Nmm.


2020 ◽  
Vol 61 (4) ◽  
pp. 596-604 ◽  
Author(s):  
Keita Nakano ◽  
Taka Narumi ◽  
Kohei Morishita ◽  
Hideyuki Yasuda

2019 ◽  
Vol 11 (5) ◽  
pp. 685-693 ◽  
Author(s):  
Zhidan Zhou ◽  
Xiubing Liang ◽  
Yongxiong Chen ◽  
Baolong Shen ◽  
Junchao Shang ◽  
...  

2010 ◽  
Vol 97-101 ◽  
pp. 1408-1411 ◽  
Author(s):  
Hui Zhang ◽  
Yi Zhu He ◽  
Ye Pan ◽  
Yin Sheng He ◽  
Kee Sam Shin

The NiCoFeCrAl3 high entropy alloy coating with a little addition of C, Si, Mn, Mo has been succesively synthesized by laser cladding. The results show that simple solution phases of ordered BCC and a small fraction of FCC are obtained with fine equaixed dendrites morphology. Because the fine grain strengthening obtained by rapid solidification and the additived small atomic elements like C, Si further increase the distortion of the solid solution lattice, The microhardness of the coating reached above 800 HV and is 50 % higher than previous study on the similar composition by arc melting technique.


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