scholarly journals Effect of Ti Content on the Microstructure and Corrosion Resistance of CoCrFeNiTix High Entropy Alloys Prepared by Laser Cladding

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2209 ◽  
Author(s):  
Xinyang Wang ◽  
Qian Liu ◽  
Yanbin Huang ◽  
Lu Xie ◽  
Quan Xu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
First Principles ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
First Principles Calculations ◽  
High Entropy ◽  
Niti Phase ◽  
Fcc Phase ◽  
Ti Content

In this paper, CoCrFeNiTix high entropy alloy (HEA) coatings were prepared on the surface of Q235 steel by laser cladding. The microstructure, microhardness, and corrosion resistance of the coatings were studied. The mechanism of their corrosion resistance was elucidated experimentally and by first-principles calculations. The results show that CoCrFeNiTi0.1 adopts a face-centered cubic (FCC) phase, CoCrFeNiTi0.3 exhibits an FCC phase and a tetragonal FeCr phase, and CoCrFeNiTi0.5 adopts an FCC phase, a tetragonal FeCr phase, and a rhombohedral NiTi phase. The FCC phase, tetragonal FeCr phase, rhombohedral NiTi phase, and hexagonal CoTi phase are all observed in the CoCrFeNiTi0.7 HEA. The alloys assume the dendritic structure that is typical of HEAs. Ni and Ti are enriched in the interdendritic regions, whereas Cr and Fe are enriched in the dendrites. With increasing Ti content, the hardness of the cladding layers also increases due to the combined effects of lattice distortion and dispersion strengthening. When exposed to a 3.5 wt.% NaCl solution, pitting corrosion is the main form of corrosion on the CoCrFeNiTix HEA surfaces. The corrosion current densities of CoCrFeNiTix HEAs are much lower than those of other HEAs. As the Ti content increases, the corrosion resistance is improved. Through X-ray photoelectron spectroscopy (XPS) and first-principles calculations, the origin of the higher corrosion resistance of the coatings is connected to the presence of a dense passivation film. In summary, the corrosion resistance and mechanical properties of CoCrFeNiTi0.5 alloy are much better than the other three groups, which promotes the development of HEA systems with high value for industrial application.

scholarly journals Phase Evolution, Microstructure and Mechanical Property of AlCoCrFeNiTi High-Entropy Alloy Coatings Prepared by Mechanical Alloying and Laser Cladding

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1036
Author(s):  
Weijie Yu ◽  
Yun Wang ◽  
Ruitao Li ◽  
Junhong Mao
Keyword(s):  
Mechanical Alloying ◽  
Laser Cladding ◽  
Steel Substrate ◽  
Phase Evolution ◽  
High Entropy Alloy ◽  
Second Phase ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Fcc Phase ◽  
Bcc Phase

AlCoCrFeNiTi high-entropy alloy coatings (HEACs) were prepared by mechanical alloying (MA) and laser cladding (LC) process on H13 hot-working die steel substrate. Phase evolution, microstructure, and mechanical properties of the alloyed powder and HEACs were investigated in detail. The final milling AlCoCrFeNiTi coating powders exhibited simple body centered cubic (BCC) phase and mean granular size of less than 4 μm. With the increase of heat input of the laser, partial BCC phase transformed into minor face centered cubic (FCC) phase during LC. AlCoCrFeNiTi HEACs showed excellent metallurgical bonding with the substrate, and few defects. Moreover, the microhardness of AlCoCrFeNiTi HEACs reached 1069 HV due to the existence of the hard oxidation and the second phase grains, which are about five times that of the substrate. The laser surface cladding HEACs exhibited deteriorated tensile property compared with that of the substrate and the fracture generally occurred in the region of HEACs. The fracture mechanism of AlCoCrFeNiTi HEACs was dominated by the comprehensive influence of brittle fracture and ductile fracture.

Laser cladding of FeCoCrNi high-entropy alloy on Ti-6Al-4V alloy: Microstructure, phase transformation and bonding region

2020 ◽  
pp. 2150037
Author(s):  
Xiaohong Zhan ◽  
Chaoqi Qi ◽  
Mengyao Wu ◽  
Lijun Liu ◽  
Zhuanni Gao
Keyword(s):  
Laser Cladding ◽  
Element Distribution ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
Rich Phase ◽  
High Entropy ◽  
Comprehensive Properties ◽  
Input Material ◽  
Face Centered ◽  
Fcc Phase

High-entropy alloys (HEAs) have shown considerable promise from both a scientific and an application perspective due to their outstanding comprehensive properties. In this study, an equiatomic FeCoCrNi HEA is used as input material for laser cladding on Ti-6Al-4V alloy. The HEA coating is characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) to investigate the bonding region, element distribution and microstructure evolution. The results show that the HEA coating is mainly composed of face-centered cubic (FCC) phase and body-centered cubic (BCC) phase, precipitating a small amount of (Fe, Cr)-rich phase and (Ni, Ti)-rich phase. Otherwise, the bonding region, which is between coating and substrate, is emphatically concerned in this paper. The bonding region is formed by the convection zone which is resulted from the density difference of HEA and TC4. In addition, the convection in molten pool plays a key role in the morphology of bonding region.

Effect of Titanium Content on Microstructure and Properties of FeWCrMnCoCuTix High Entropy Alloy Coating Prepared by Laser Cladding

2014 ◽  
Vol 563 ◽  
pp. 25-29
Author(s):  
Xu Long An ◽  
Qi Bin Liu ◽  
Bo Zheng
Keyword(s):  
Laser Cladding ◽  
Alloy Coating ◽  
Titanium Content ◽  
Experimental Result ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Microstructure And Properties ◽  
Simple Body ◽  
Ti Content

To obtain the coating with excellent properties, FeWCrMnCoCuTix(x=0.2, 0.4, 0.6) high entropy alloys coating on 45 steel were prepared by laser cladding. By means of OM, XRD and microhardness tester, the effect of Ti content on microstructure and properties of coating is investigated. The experimental result shows that the phase composition of HEAs coating is simple body-centered cubic and face-centered cubic. The microstructure of these alloys is mainly dendrite crystal with grains were fine and uniform. When Ti content increases tox=0.4, the hardness of the coating reaches a maximum (639HV0.2). Key words: HEAs; FeWCrMnCoCuTix; coating; laser cladding; microstructure and properties

scholarly journals Influence of Aluminum and Molybdenum on the Microstructure and Corrosion Behavior of Thermally Sprayed High-Entropy Alloy Coatings

2021 ◽  
Author(s):  
Martin Löbel ◽  
Thomas Lindner ◽  
Maximilian Grimm ◽  
Lisa-Marie Rymer ◽  
Thomas Lampke
Keyword(s):  
Corrosion Resistance ◽  
Protective Coatings ◽  
Base Alloy ◽  
Alloy System ◽  
High Entropy Alloy ◽  
Oxide Content ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Structural And Functional Properties ◽  
Wide Range

AbstractHigh-entropy alloys (HEAs) have shown a wide range of promising structural and functional properties. By the application of coating technology, an economical exploitation can be achieved. The high wear and corrosion resistance of HEAs make them particularly interesting for the application as protective coatings. Especially for alloys with a high chromium content, a high corrosion resistance has been revealed. For the current investigations, the equimolar HEA CrFeCoNi with a single-phase face centered cubic structure is considered as a base alloy system. To increase the corrosion resistance as well as the hardness and strength, the influence of the alloying elements aluminum and molybdenum is analyzed. For the current investigations, the high kinetic process high-velocity oxygen fuel thermal spraying (HVOF) has been considered to produce coatings with a low porosity and oxide content. Feedstock is produced by inert gas atomization. The influence of the alloy composition on the microstructure, phase formation and resulting property profile is studied in detail. A detailed analysis of the corrosion resistance and underlying mechanisms is conducted. The pitting and passivation behavior are investigated by potentiodynamic polarization measurements in NaCl and H2SO4 electrolyte. A distinct improvement of the corrosion resistance can be achieved for the alloy Al0.3CrFeCoNiMo0.2.

Phase decomposition and strengthening in HfNbTaTiZr high entropy alloy from first-principles calculations

2021 ◽  
pp. 117582
Author(s):  
Shu-Ming Chen ◽  
Ze-Jun Ma ◽  
Shi Qiu ◽  
Lian-Ji Zhang ◽  
Shang-Zhou Zhang ◽  
...  
Keyword(s):  
First Principles ◽  
High Entropy Alloy ◽  
Phase Decomposition ◽  
First Principles Calculations ◽  
High Entropy

scholarly journals Effect of Mn Addition on the Microstructures and Mechanical Properties of CoCrFeNiPd High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 288
Author(s):  
Yiming Tan ◽  
Jinshan Li ◽  
Jun Wang ◽  
Hongchao Kou
Keyword(s):  
Intermetallic Compound ◽  
Interface Energy ◽  
High Entropy Alloy ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
Liquid Interfaces ◽  
High Entropy ◽  
Single Face ◽  
Face Centered ◽  
Fcc Phase

CoCrFeNiPdMnx (x = 0, 0.2, 0.4, 0.6, 0.8) high entropy alloys (HEAs) were prepared and characterized. With an increase in Mn addition, the microstructures changed from dendrites (CoCrFeNiPd with a single face-centered-cubic (FCC) phase) to divorced eutectics (CoCrFeNiPdMn0.2 and CoCrFeNiPdMn0.4), to hypoeutectic microstructures (CoCrFeNiPdMn0.6), and finally to seaweed eutectic dendrites (CoCrFeNiPdMn0.8). The addition of Mn might change the interface energy anisotropy of both the FCC/liquid and MnPd-rich intermetallic compound/liquid interfaces, thus forming the seaweed eutectic dendrites. The hardness of the FCC phase was found to be highly related to the solute strengthening effect, the formation of nanotwins and the transition from CoCrFeNiPd-rich to CoCrFeNi-rich FCC phase. Hierarchical nanotwins were found in the MnPd-rich intermetallic compound and a decrease in either the spacing of primary twins or secondary twins led to an increase in hardness. The designing rules of EHEAs were discussed and the pseudo binary method was revised accordingly.

scholarly journals An investigation of high entropy alloy conductivity using first-principles calculations

2021 ◽  
Vol 119 (12) ◽  
pp. 121903
Author(s):  
Vishnu Raghuraman ◽  
Yang Wang ◽  
Michael Widom
Keyword(s):  
First Principles ◽  
High Entropy Alloy ◽  
First Principles Calculations ◽  
High Entropy

scholarly journals Microstructure Evolution and Properties of Laser Cladding CoCrFeNiTiAlx High-Entropy Alloy Coatings

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 373 ◽  
Author(s):  
Yiku Xu ◽  
Zhiyuan Li ◽  
Jianru Liu ◽  
Yongnan Chen ◽  
Fengying Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Laves Phase ◽  
High Entropy Alloy ◽  
Body Centered Cubic ◽  
Phase Constitution ◽  
High Entropy ◽  
Al Content ◽  
Wear And Corrosion ◽  
Wear And Corrosion Resistance

High-entropy alloy (HEA) coatings of CoCrFeNiTiAlx (x = 0, 0.5, 1, 1.5, 2) were prepared on the surface of AISI1045 steel by laser cladding. The effects of the Al content on the microstructure, composition, phase constitution, and wear and corrosion resistance of the coatings were investigated. The results showed that when increasing the Al element content from 0 to 0.5, the phase constitution of the CoCrFeNiTiAlx coating changed from a single Face-centered cubic (FCC) phase to Body-centered cubic 1 (BCC1) and Body-centered cubic 2 (BCC2) phases, with a small amount of Laves phase, which obviously improved the friction and corrosion resistance of the coating. With further enhancing of the Al content, the amount of BCC1 phase increased, while the BCC2 phase and the Laves phase decreased. The CoCrFeNiTiAl2 HEA coating transformed into a single BCC1 phase, with retrogressive wear and corrosion resistance. It was found that the Al0.5 alloy coating exhibits excellent wear resistance, high hardness, and corrosion resistance in a 3.5 wt.% NaCl solution. Furthermore, the effect of the Al content on the microstructure, phase, and the relating properties of the CoCrFeNiTiAlx HEA coatings is also discussed.

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