Study on Wear Resistance of Nickel Cladding Layer with Imitation Shell Convex Strip Structure on the Surface of 7075 Aluminum Alloy Drill Pipe

Round 1

Reviewer 1 Report

The biomimetism is a well-known design to improve the wear resistance of metal surfaces. In view of reducing the wear loss, the authors applied the laser cladding over a 7075 Al alloy, reproducing a pattern inspired by the shell convex structure. In comparison with the smooth coating, the shell-type structure coating exhibited a great reduction in mass loss and improved the lifetime of the cladding.

The study showed compelling results however there are some issues:

1 – The English must be revised. There are grammar errors, typos, absence of commas, and some sentences are too long. The formatation of the manuscript must be also revised;

2 – About Keywords, “coarse and fine grain areas” seems not to be relevant to the study. I suggest to exclude;

3 – Please, check if references 7 and 21 are correct. On p. 2, lines 56-58: “Laser cladding has been proven ... pipes’ surface [11-14]”, none of the references are related to the statement, check if the references are correct;

4 – P. 5, lines 139-141: “It can be seen ... 9 groups was 0.46”. This sentence is confusing, I suggest to rewrite it;

5 – Figure 5: Increase the size of the detail, it is hard to see the dimensions;

6 – Figure 7: Draw the y axis;

7 – Table 2: Where were the material properties extracted from? Cite the references;

8 – Equations 1, 2, and 4 were not mentioned in the text. In Equation 2, what is the correct Symbol for speed? V_S or L?;

9 – P. 7, line 202: “conditions in the red box need”, is the correct color red or blue?;

10 – What is the reason to adopt 0.1 s for the time simulation? Is it suitable based on the wear tests, that lasted 40 minutes?;

11 – What are the chemical compositions of the 7075 Al alloy and Ni powder? It is important to provide this information;

12 – Some details about the cladding is missing, such as the power and scanning speed of the laser, the thickness of the coating (in both configuration), what is the light-absorbing material and how was the homogeneity of the cladding;

13 – The shell-type structure coating was not convex, but parallel stripes. So, it seems that the term “convex structure” is not true. Reconsider if “convex” is appropriate;

14 – Figure 10: Correct the term “Ladding” for “Cladding”;

 

15 – Figure 12: The symbol ω was not explained;

16 – Table 3: In the caption, specify which Figure the location was referenced to;

17 – P. 10, line 227: Please, confirm if the rotation direction is correct;

 

18 – Include scale in Figure 16a;

19 – P. 14, lines 362-364: “which indicates that the cause... condensation of Al fusion”. Do the authors know of any references or other evidence to support this claim? Is the difference in grain refinement due to recrystallization or remelting?;

20 – In the caption of Figures 18 and 20, EDS was not defined and there are typo;

21 – P. 15, lines 385-386: “the main composition of the cladding layer is AlNi eutectic phase”, from the presented results, it is not possible to confirm that is an eutetic phase. It would be better to cite “AlxNiy phase” or “AlNi-type phase”;

22 – Figure 21, the graph lacks a title axis and y-axis;

 

23 – Provide the errors/standard deviation of the wear and hardness tests;

24 – From Figure 24, it is not possible to observe clearly the wear regions. Provide images with higher magnification.

The English must be revised. There are grammar errors, typos, absence of commas, and some sentences are too long.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

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Comments for author File: Comments.docx

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The present manuscript deals with the study of wear resistance of nickel cladding layer with convex structure on the surface of the aluminum alloy. It is well written and discussed and contains enough experimental results and simulations. However, some major revision is mandatory before it can be considered for publication. The main comments and questions are summarized below:

1. Introduction – text written between lines 73 and 85 is more like an abstract. It should be rewritten in connection with motivation, which should be highlighted.

2. Figs. 3 and 9 are useless – the description given in the text form is sufficient.

3. Table 1 and Fig. 1 could be connected – symbols from Table 1 should be added to Fig. 1.

4. The radiation (anode material) should be specified in the description of XRD (line 262).

5. In which state of heat treatment is the studied material 7075? Please specify.

6. Units should be added to Figs. 13 and 14.

7. The diameter of the pipe is given as 146 mm in the experimental part, while in the simulation 147 mm is mentioned. Please explain.

8. What was the motivation to use such parameters in simulations? Why are the simulation parameters different from those used in the experimental testing?

9. Fig. 16 – the scale is missing. In addition, the magnification mentioned in the figure caption should be removed, since it no longer applies if the dimensions of the images are changed once from the original. The description like “overview” and “detail” should be used instead.

10. Figure captions of Figs. 18 and 20 are confusing due to the wrong EDS abbreviation (EDS vs EDC vs ECS). Please correct.

11. EDS spectra alone provide little information only. It would be interesting to summarize and discuss the chemical composition of measured points. Besides that, the EDS mapping of investigated areas would be useful as well.

12. Fig. 21 – to increase the scientific soundness of the XRD pattern, Miller indices should be included.

13. Fig. 22 – the standard deviation should be included. How many measurements per area were done?

14. Why were the radii between the horizontal and vertical parts of the convex structure not designed? Increased stresses in sharp corners were be expected.

 

Besides the above comments and questions, some formal editing is also mandatory:

- authors’ affiliations should be reformatted,

- lines 46, 47 and 64 – the form of citation format should be corrected, e.g., “…pipes. [2-4]However…” --- > “…pipes [2-4]. However…”,

- lines 64 and 66 – YANG ---> Yang, CHEN ---> Chen,

- please check spaces throughout the whole manuscript,

- lines 189-190 – superscripts should be used (e.g., 10^-8),

- blank line should be inserted between lines 189 and 190, and between 330 and 331,

- lines 200 and 213 – comprises of ---> comprises,

- line 220 – CO2 ---> CO₂,

- line 251 – the the,

- please check the format of references (spaces, font, etc.).

Minor editing of English language is required.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear authors,

Thank you for answering point by point the questions I've asked.

There are some minor issues:

- Fig. 3: It seems that the legend is not totally visible;

- Fig. 8: In the detail of the HAZ, "Ladding" is not correct.

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

see file

Comments for author File: Comments.docx

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The authors sufficiently reflected all the comments and questions in the revised manuscript. However, there the new question appeared (resulting from EDX maps), which should be answered before the manuscript can be recommended for publication:

- In EDX maps, Al overlaps with Ni in small area only. Surprisingly, It seems to be in contradiction with Fig. 18, based on which the authors stated that "the main composition of the cladding layer is Al_xNi_y". The most signinificant element in the upper part of maps (which I guess corresponds to the cladding layer) is Ni and there is almost no Al, except one small area where it seems to occur with Ni (this area could correspond to Al₃Ni₂). The authors should give a statement and clarify the phase analysis study in connection to the microstructure. Besides that, the authors could also visually dinstinguish the particular microstructural regions in the EDX maps.

Author Response

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Round 3

Reviewer 2 Report

Ok

Reviewer 3 Report

The authors answered the question sufficiently, therefore the manuscript can be recommended for publication in its current form.