Effect of Y on Microstructure and Properties of Al0.8FeCrCoNiCu0.5 High Entropy Alloy Coating on 5083 Aluminum by Laser Cladding
, Hongxin Wang 1,3, Binjun Zhou 1,3, Defa Li 1,3, Hua Lin 1,3 and Junqi Wang 1,3
Round 1
Reviewer 1 Report
In this paper, the phase composition, microstructure, microhardness, corrosion, and wear properties of laser-cladding Al0.8FeCrCoNiCu0.5Yx high-entropy-alloy (HEA) coatings on aluminum surfaces were studied. It is an interesting idea to use HEA coating to restrain the cracking of aluminum surfaces based on a high entropy effect. The idea and research results described in this manuscript are of certain interest and scientific value. I suggest that this manuscript could be considered for acceptance after the revisions according to the following questions could be made.
1. In the introduction section, why did you choose this kind of coating to be deposited on top of aluminum alloy?
2. The experimental details of XRD, SEM, and hardness tests should be provided.
3. It seems that the coatings of Y0.1 and Y0.2 have similar hardness, but why do they exhibit different wear rates? A detailed explanation should be provided.
4. Figure 5: Why is the composition of Al0.1 in the figure caption?
5. The Introduction part is not comprehensive. For example, many recent works focus on the microstructure and mechanical properties of laser cladding. You can refer to Coatings, 2022, 12(10), 1537; https://doi.org/10.3390/coatings12101537
Author Response
Point 1: In the introduction section, why did you choose this kind of coating to be deposited on top of aluminum alloy?
Response 1: The introduction of the manuscript has been added, and the content is as follows:
In summary, HEAs have good mechanical properties and corrosion resistance, which enable them as coatings. More importantly, Al has a large solubility in HEA systems containing Co, Fe, Cr, Ni, and Cu elements, which means that the Al in the substrate and the added powder will tend to form solid solutions after the reaction reducing the susceptibility of the coating to cracking. It indicates that the HEA can potentially improve the surface properties of Al substrates. But this theory is still required to be verified by experiments. In addition, Al has been proven to improve the mechanical properties of HEA due to its large atomic radius and the ability to promote the formation of the BCC phase. It would be interesting to study the influence of Al on the properties of as-cladding HEA coating containing Fe, Co, Ni, Cr, and Cu elements. However, there are few studies on using Al-Cr-Fe-Co-Ni-Cu HEAs as a coating to improve the surface properties of aluminum.
Point 2: The experimental details of XRD, SEM, and hardness tests should be provided.
Response 2: Thanks for spotting it. The test instrument's relevant parameters are added. The modifications are as follows:
The physical phase analysis of the coating was performed using an Empyrean X-ray diffractometer with a Cu target, a tube voltage of 40 kV, a scanning speed of 4° /min, and a scanning angle step of 0.05°. The JSM-6510LA SEM was selected for micro-structure observation. MH-60 microhardness tester was used to test the coating hardness. The load was 200g, the loading time was 10s, and the average value of three specimens was taken. MM200 friction was selected for dry-sliding wear testing, load loading was 98 N, and test time was 30min. The friction block was a GCr15 steel ring with a hardness of 61 HRC. Frictional wear data are recorded during the frictional wear test, and the test is repeated 3 times to obtain the average value. Zaner's electrochemical workstation is selected for the polarization test. The polarization test uses an electrochemical workstation(Zahner, Zennium Pro). The experiment was carried out at room temperature. A three-electrode working system was used: the working electrode was the experimental sample (WE), the counter electrode (CE) was platinum, and the reference electrode (RE) was a saturated KCl solution. Select 3.5%NaCl solution for corrosion solution. The scanning range of the polarization curve test is - 2~1V. The scan rate was 5mV/s.
Point 3: It seems that the coatings of Y0.1 and Y0.2 have similar hardness, but why do they exhibit different wear rates? A detailed explanation should be provided.
Response 3: Although the hardness of Y0.1 coating and Y0.2 coating are similar, the wear rate of Y0.1 coating is lower, the reason may be speculated as follows. As shown in Fig.5 (e), Y0.2 has a large welding area. Under the repeated action of the friction pair pressure, the edge of the wear surface of the coating appears to be tilted to a certain extent, the wear groove has undergone plastic deformation, and the ap-pearance of the flocculent structure indicates that the alloy has experienced oxidation reaction during the wear process. The wear surface of Y0.2 is rougher than that of Y0.1. On the other hand, XRD showed that Y element appeared in Y0.2, and the single phase also affected the wear resistance of the coating during the friction process.
Point 4: Figure 5: Why is the composition of Al0.1 in the figure caption?
Response 4: It was a careless oversight. Thanks for spotting it. I have corrected the caption of Figure 2. The modifications are as follows:
Figure 2. A typical microstructure of the Al0.8FeCrCoNiCu0.5Yx HEA coatings((a) is the microstructure of Y0; (b) is the microstructure of Y0.05; (c) is the microstructure of Y0.1; (d) is the microstructure of Y0.2).
Point 5: The Introduction part is not comprehensive. For example, many recent works focus on the microstructure and mechanical properties of laser cladding. You can refer to Coatings, 2022, 12(10), 1537; https://doi.org/10.3390/coatings12101537.
Response 2: The introduction part of the manuscript is supplemented.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
In this paper, Al0.8FeCrCoNiCu0.5Yx (x = 0, 0.05, 0.1, and 0.2) high-entropy alloy coatings were prepared by laser cladding to improve the surface properties of aluminum. And the effect of Y on the microstructure and properties of the coating was analyzed. The paper has some interesting results that could make it publishable in the journal of Lubricants after the following major revisions:
1- Please check the English language of the paper.
2-Abstract needs modification. Write in the abstract what has been done and then talk about the parameters studied and then the main results.
3-Introduciton should be strengthened. Some old references are used. To modify this section the following documents can be consulted:
-Jointing of CFRP/5083 Aluminum Alloy by Induction Brazing: Processing, Connecting Mechanism, and Fatigue Performance. Coatings, 12(10), (2022)1559. doi: https://doi.org/10.3390/coatings12101559
-Water jet impact damage mechanism and dynamic penetration energy absorption of 2A12 aluminum alloy. Vacuum, 206, (2022). 111532. doi: https://doi.org/10.1016/j.vacuum.2022.111532
- Effects of minor Nd and Er additions on the precipitation evolution and dynamic recrystallization behavior of Mg–6.0Zn–0.5Mn alloy. Journal of magnesium and alloys, 9(3), (2021) 840-852. doi: 10.1016/j.jma.2020.06.018
5-The methods used for the microstructural analysis, hardness and corrosion performance should be mentioned in the materials and method section..
6-Add standard deviation to the hardness results.
7-Use these references in the results/discussion section:
-Effect of heat treatment process on the micro machinability of 7075 aluminum alloy. Vacuum, 207, (2023). 111574. doi: https://doi.org/10.1016/j.vacuum.2022.111574
-Effect of aging plus cryogenic treatment on the machinability of 7075 aluminum alloy. Vacuum, 208, (2023). 111692. doi: https://doi.org/10.1016/j.vacuum.2022.111692
- Microstructural origin and control mechanism of the mixed grain structure in Ni-based superalloys. Journal of Alloys and Compounds, 900, (2022) 163515. doi: https://doi.org/10.1016/j.jallcom.2021.163515
8-Mention the standards used for the various properties evaluation.
9-It is conclusions not conclusion.
10-mention the type of aluminum 5083 in the title and the abstract.
Author Response
Point 1: Please check the English language of the paper.
Response 1: I have corrected the grammar problems and spelling mistakes in the manuscript.
Point 2: Abstract needs modification. Write in the abstract what has been done and then talk about the parameters studied and then the main results.
Response 2: Thanks for spotting it. The modifications are as follows:
To improve the surface properties of 5083 aluminum, Al0.8FeCrCoNiCu0.5Yx (x = 0, 0.05, 0.1, and 0.2) high-entropy alloy coatings were prepared by laser cladding. The phase structure and microstructure of the Al0.8FeCrCoNiCu0.5Yx coatings were characterized by XRD and SEM. The tribological properties of the coating were tested by friction and wear tester. The corrosion resistance of the coating was tested by electrochemical workstation. The results show that when Y content is less than 0.2, the Al0.8FeCrCoNiCu0.5Yx coating is in the FCC1, BCC1, and BCC2 phases. When Y is added to 0.2, the coating appears rich in the Y phase. With the increased Y content, the hardness of the coating can increase. The average hardness of Y0, Y0.05, Y0.1, and Y0.2 are 479HV0.2, 517HV0.2, 532HV0.2, and 544HV0.2, respectively. Microstructure evolution leads to an increase in the hardness of the coating. The effect of Y on the wear resistance of the Al0.8FeCrCoNiCu0.5Yx coatings is consistent with the hardness. Al0.8FeCrCoNiCu0.5Y0.2 coating has the lowest wear rate，and its wear rate is 8.65×10-6mm3/Nm. The corrosion current density of Al0.8FeCrCoNiCu0.5Y0.05 and Al0.8FeCrCoNiCu0.5Y0.1 coatings is in the order of 10-8, which is less than Al0.8FeCrCoNiCu0.5Y0.2 and Al0.8FeCrCoNiCu0.5. The performance of each component coating is superior to that of the substrate.
Point 3: Introduciton should be strengthened. Some old references are used. To modify this section the following documents can be consulted:
-Jointing of CFRP/5083 Aluminum Alloy by Induction Brazing: Processing, Connecting Mechanism, and Fatigue Performance. Coatings, 12(10), (2022)1559. doi: https://doi.org/10.3390/coatings12101559
-Water jet impact damage mechanism and dynamic penetration energy absorption of 2A12 aluminum alloy. Vacuum, 206, (2022). 111532. doi: https://doi.org/10.1016/j.vacuum.2022.111532
- Effects of minor Nd and Er additions on the precipitation evolution and dynamic recrystallization behavior of Mg–6.0Zn–0.5Mn alloy. Journal of magnesium and alloys, 9(3), (2021) 840-852. doi: 10.1016/j.jma.2020.06.018
Response 3: Thanks to expert advice, references have been included in the introduction.
Point 5: The methods used for the microstructural analysis, hardness and corrosion performance should be mentioned in the materials and method section.
Response 5:
Thanks for spotting it. The test instrument's relevant parameters are added. The modifications are as follows:
The physical phase analysis of the coating was performed using an Empyrean X-ray diffractometer with a Cu target, a tube voltage of 40 kV, a scanning speed of 4° /min, and a scanning angle step of 0.05°. The JSM-6510LA SEM was selected for micro-structure observation. MH-60 microhardness tester was used to test the coating hardness. The load was 200g, the loading time was 10s, and the average value of three specimens was taken. MM200 friction was selected for dry-sliding wear testing, load loading was 98 N, and test time was 30min. The friction block was a GCr15 steel ring with a hardness of 61 HRC. Frictional wear data are recorded during the frictional wear test, and the test is repeated 3 times to obtain the average value. Zaner's electrochemical workstation is selected for the polarization test. The polarization test uses an electrochemical workstation(Zahner, Zennium Pro). The experiment was carried out at room temperature. A three-electrode working system was used: the working electrode was the experimental sample (WE), the counter electrode (CE) was platinum, and the reference electrode (RE) was a saturated KCl solution. Select 3.5%NaCl solution for corrosion solution. The scanning range of the polarization curve test is - 2~1V. The scan rate was 5mV/s.
Point 6: Add standard deviation to the hardness results.
Response 6: The manuscript has been corrected as required.
Point 7: Use these references in the results/discussion section:
-Effect of heat treatment process on the micro machinability of 7075 aluminum alloy. Vacuum, 207, (2023). 111574. doi: https://doi.org/10.1016/j.vacuum.2022.111574
-Effect of aging plus cryogenic treatment on the machinability of 7075 aluminum alloy. Vacuum, 208, (2023). 111692. doi: https://doi.org/10.1016/j.vacuum.2022.111692
- Microstructural origin and control mechanism of the mixed grain structure in Ni-based superalloys. Journal of Alloys and Compounds, 900, (2022) 163515. doi: https://doi.org/10.1016/j.jallcom.2021.163515
Response 7: Thanks to expert advice, references have been included in the results/discussion section.
Point 8: Mention the standards used for the various properties evaluation.
Response 8: Thanks for spotting it. The modifications are as follows:
The physical phase analysis of the coating was performed using an Empyrean X-ray diffractometer with a Cu target, a tube voltage of 40 kV, a scanning speed of 4° /min, and a scanning angle step of 0.05°. The JSM-6510LA SEM was selected for micro-structure observation. MH-60 microhardness tester was used to test the coating hardness. The load was 200g, the loading time was 10s, and the average value of three specimens was taken. MM200 friction was selected for dry-sliding wear testing, load loading was 98 N, and test time was 30min. The friction block was a GCr15 steel ring with a hardness of 61 HRC. Frictional wear data are recorded during the frictional wear test, and the test is repeated 3 times to obtain the average value. Zaner's electrochemical workstation is selected for the polarization test. The polarization test uses an electrochemical workstation(Zahner, Zennium Pro). The experiment was carried out at room temperature. A three-electrode working system was used: the working electrode was the experimental sample (WE), the counter electrode (CE) was platinum, and the reference electrode (RE) was a saturated KCl solution. Select 3.5%NaCl solution for corrosion solution. The scanning range of the polarization curve test is - 2~1V. The scan rate was 5mV/s.
Point 9: It is conclusions not conclusion.
Response 9: The manuscript has been corrected as required.
Point 10: Mention the type of aluminum 5083 in the title and the abstract.
Response 10: The manuscript has been corrected as required. The modifications are as follows:
Title:Effect of Y on microstructure and properties of Al0.8FeCrCoNiCu0.5 high entropy alloy coating on 5083 Aluminum by laser cladding
Abstract: To improve the surface properties of aluminum, Al0.8FeCrCoNiCu0.5Yx (x = 0, 0.05, 0.1, and 0.2) high-entropy alloy coatings were prepared on 5083 Aluminum by laser cladding.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
It can be accepted.
Reviewer 2 Report
The paper can be accpeted in present form.
Reviewer 3 Report
Required revisions were made. The paper can be accepted in its current format.
