Investigation into Microstructure, Wear Resistance in Air and NaCl Solution of AlCrCoNiFeCTax High-Entropy Alloy Coatings Fabricated by Laser Cladding
Round 1
Reviewer 1 Report
In the manuscript, “Investigation into microstructure, wear resistance in air and NaCl solution of AlCrCoNiTax high-entropy alloys coatings fabricated by laser cladding” authors studied microstructure, mechanical properties (especially wear behaviors in air and NaCl solution) of AlCrCoNiTax high-entropy alloys coatings. The article is original and well-written. Authors found that different amount of Ta (x=0; 0,5; 1) in AlCrCoNiTax alloy influence on the phase transformation from BCC+fine MC (M=Al, Cr, Co and Ni) particles into BCC +coarse/fine TaC particles, finally into BCC+coarse TaC particles+lamellar eutecticum (BCC+TaC). The microhardness and wear resistance of the coatings are gradually increased with the increasing of the Ta content.
I have some comments:
- In the introduction section, besides mentioned methods of improving wear properties of steel could also be noted electron beam treatment (for example see:
Guan, Q.-F., Dong, S.-H., Zheng, H.-H., Li, C., Zhang, C.-L., Lv, P. Cr surface alloying of 45# steel by high-current pulsed electron beam treatment (2018) Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University (Engineering and Technology Edition), 48 (4), pp. 1161-1168. https://doi.org/10.13229/j.cnki.jdxbgxb20161280
Gromov, V.E., Gorbunov, S.V., Ivanov, Y.F., Vorobiev, S.V., Konovalov, S.V. Formation of surface gradient structural-phase states under electron-beam treatment of stainless steel (2011) Journal of Surface Investigation, 5 (5), pp. 974-978. DOI: 10.1134/S1027451011100107
Zhang, K., Zou, J., Grosdidier, T., Dong, C. Formation and evolution of craters in carbon steels during low-energy high-current pulsed electron-beam treatment (2009) Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 27 (5), pp. 1217-1226. DOI: 10.1116/1.3207948). - Some peaks in the XRD patterns were not indicated. Please, add this information or explain why those peaks were not indicated.
- In table 2 it was demonstrated that some particles such as coarse blocky or spherical ones are mostly composed of C atoms. Therefore, it might be concluded that C has a significant influence on the microstructure of the obtained coatings. What are the main sources of C atoms in the coatings? Did they come from the substrate or from the polyvinyl alcohol by which substrate was covered or from the other sources?
Author Response
Dear reviewer,
Firstly, thanks for your careful review for my paper. Based on your advice, we had revised my paper in detail, and the revised parts had been marked in red in revised manuscript.
Detailed corrections are listed in the file attached.
Yours sincerely
Jun Li
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This study by P. Zhao et. al., reports on the investigation into the microstructure, wear resistance in air and NaCl solution of AlCrCoNiTax high entropy alloys coatings fabricated using laser cladding. The authors have carried out a systematic investigation on three different HEA coating compositions and did a good job in explaining their work. These findings are likely to be of interest to the high entropy alloys community in developing coatings with good tribological properties. Overall, this is a nice work by identifying and addressing a problem that has not been studied yet. Although this work appears very interesting, there are a few minor issues that need to be addressed before the manuscript can be accepted by the journal
- Please include the standard deviation for hardness values
- In Fig. 1, please label the peaks for coating III
- Some of the sentences in the introduction were not properly written and makes it difficult for readers to understand. Therefore, the reviewer recommends the authors rewrite some parts for easy follow.
Author Response
Dear reviewer,
Firstly, thanks for your careful review for my paper. Based on your advice, we had revised my paper in detail, and the revised parts had been marked in red in revised manuscript.
Detailed corrections are listed in the file attached.
Yours sincerely
Jun Li
Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript is dedicated to the study of preparation and properties of novel HEA coatinng. There is a significant volume of data shown in the manuscript. The overal quality is quite good, but it still has many issues that have to be fixed. Please improve the manuscript according to the comments bellow:
0-The most important comment: The authors completely forgot about the carbon. Only the alloy ocmpositions AlCrCoNiTax is always mentioned, but they did not consider there is also carbon present in all coating. Please change the manuscript accordingly, as well as the original title to reflect this. It should be AlCrCoNiCTax
1-In the introduction, it is written that “However, poor wear resistance resulting from its low surface hardness severely restricts its more extensive application as friction components” This is not completely true because hardness of certain steel can reach 900HV, which is higher value than the coatings showed in this study. Please Improve introduction to be more scientifically correct.
2- There are several grammar mistakes in the manuscript – please correct them, it should be quite simple as they look more like a results of oversight. Such as “however accompanied with which the low toughness will be involved in the coatings” etc
3- “The combination of high entropy alloy effect, hysteresis diffusion ef- 55 fect, lattice distortion effect and cocktail effect can endow the alloy with high …” This statements in the introduction are all old and proven to be wrong. Please delete it as nobody knows, what is for instance so called “cocktail effect” – or what is High entropy alloy effect? Please explain
4- “This result proposes a new strategy to solve the incompatibility between the two 61 involved in hard ceramic particles reinforced metal matrix coatings prepared by laser 62 cladding.” – what is the strategy exactly? You forgot to write it
5- What is “45#” steel? Please show some standard designation, I understand that it is probably European standard C45 carbon steel, but it has to be explained.
6- There are several peaks in the XRD patterns of Fig. 1, which are not identified or marked (peaks at ~38degrees etc..). Show the results and discuss them.
7- How was this finding discovered? “There are a high G and a very low R at the interface”, please explain this in more detail
8- “TaC as the solvent 233 and Al, Co, Cr, Ni and Fe as the solutes.” I do not think that the Al, Ni or Co would have a sufficient affinity for C – they would not go to solution in TaC carbide. It is possible that the residual elements (Co,NiCr Al) are found in the EDS spectra’s as the background noise in the signal from matrix phase. Please include this into discussion.
9- Where is the proof of this assumptions: “During laser cladding, the elemental distribution is 238 considerably inhomogeneous. TaC as a high melting point of about 3800 °C will be pref- 239 erentially precipitated in the molten pool. TaC will grow into the coarse blocky particles 240 in some zones rich in Ta. However, the other fine TaC particles may grow in a compara- 241 tively low speed in the other zones poor in Ta. Fine TaC particles will be pushed to the 242 grain boundaries along with the gradual growth of the BCC sold solution, resulting in the 243 formation of discontinuous skeleton”
This all seems possible, but highly speculative. The microstructure also looks like a normal eutectic structures.
10- Fig 3 d seems like it is composed of two images (SE and BSE?)- why are the other images not all done like this? Where is the explanation of this?
11- In the entire manuscript, I did not find a single mention, of how so much carbon got to the coating? It is obvious it originates from the polymer used for preparation, but it has to be explained. Also, what are the exact carbon concentrations in the coating?
12-What are the volume fractions of carbides from the XRD measurements?
13- The authors only compare the coating between each other. However, some comparison with the references is needed, toreally show the properties. Include some discussion and comparison with other studies such as:https://doi.org/10.1016/j.matchar.2019.110046.
Author Response
Dear reviewer,
Firstly, thanks for your careful review for my paper. Based on your advice, we had revised my paper in detail, and the revised parts had been marked in red in revised manuscript.
Detailed corrections are listed in the file attached.
Yours sincerely
Jun Li
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors have made all corrections. No new comments.
Reviewer 3 Report
The authors did a good job improving all the neccesary points according to my review in a very short time.
Therefore manuscript can be accepted in present form.
