The Mode Deformation Effect on Surface Nanocrystalline Structure Formation and Wear Resistance of Steel 41Cr4

Round 1

Reviewer 1 Report (New Reviewer)

Some major  revisions need to be addressed before the paper is to be accepted for publishing

Comments for author File: Comments.docx

Author Response

Response to Reviewer 1

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

 

In this work, the authors studied the effect of mechanical pulse treatment on microhardness, surface topography, and wear resistance of 41Cr4 steel. The paper is interesting and novel. It is publishable subject to revision.

1.The chemical composition of the 41Cr4 steel should be provided in the materials and methods section.

2.Reference [22] is written in Russian. Since the audience of the journal is international, please, consider providing an English reference instead.

3. The text on lines 74-99 relates to the technology of mechanical pulse treatment. It should be moved to the introduction.

4.The authors speak about “surface nanocrystalline structure formation” in the title, however, only low-resolution images of the 41Cr4 steel surface are provided (Fig. 4 c, d, Fig. 8). Please, provide some HR TEM images to confirm the nanocrystalline structure formation.

5.Decimal dots should be used instead of commas in Table 1.

6.Please, use color in Fig. 7 to make the columns legible.

Author Response

Response to Reviewer 2

Author Response File: Author Response.pdf

Reviewer 3 Report (New Reviewer)

In this work, the formation of strengthened surface layers with nanocrystalline structure during mechanical-pulse treatment is used to increase the hardness and wear resistance. The results are important and the improved friction and wear properties are desirable. Before accept, the introduction section should be improved with more descriptions and references. In addition, the authors should characterize the surface roughness of friction pairs after polish.

 

Author Response

Response to Reviewer 3

Author Response File: Author Response.pdf

Reviewer 4 Report (New Reviewer)

The article “The Mode Deformation Effect on Surface Nanocrystalline Structure Formation and Wear Resistance of Steel 41Cr4” provides a new method to improve the wear resistance of steel 41Cr4 by SPD.  This is a good work and the results are interesting.  

Well, there are some questions need solve.

1. The English need improved, some sentences are too long and unreadable. Such as, page 1, line 31to line 36, “The study of the nature of the surface of metal materials and methods of its intentional modification to achieve some required physical and mechanical properties are under the great attention of scientists and engineers for a long time ” ; “page 2, line 59 to line 62, this paragraph is only one sentence. Page2, line 75 to line 77, “modernized surface or circular grinding machines (for strengthening flat or cylindrical surfaces, respectively) and lathes with the device with an autonomous tool drive installed instead of the tool-post are used” etc. Please check the whole text.

2. Normally, we use “heat treatment” instead of “thermal treatment” in materials science.

3. It need present the XRD spectrum of the α-phase of the surface nanocrystalline structure layer of steel 41Cr4.    

4. Why the authors present the TEM images of steel C45 studied in another paper, and not Steel 41Cr4 in this paper?  

5. What kind of microhardness does the Hμ stand for?

6. “In the zone of their contact, a unit load of ~ 0.8…1.0 GPa is created”, how to measure the load?

7. The figure 7 should be given an obvious hint in the text. Otherwise, the readers don’t know what the authors talking about.

Author Response

Response to Reviewer 4

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report (New Reviewer)

Manuscript has been greatly enhanced in quality

I accept to publish this paper  

Reviewer 2 Report (New Reviewer)

Authors answered my comments and improved their manuscript. It is acceptable for publication.

Reviewer 4 Report (New Reviewer)

The manuscript has been revised carefully according to the reviewers' comments. 

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This paper reports the microstructure, micro-hardness profile and sliding friction and wear properties of two mechanical pulse treated steel samples. Although the scope of the research was valuable, and the results presented are interesting. But the major results presented are of poor quality and not acceptable for publication. A few examples are given below.

1.       The microstructure characterization was poorly presented by cross-sectional SEM and TEM. The SEM images in Figure 4 show low resolution. The TEM images in Figure 6 are also not acceptable for the quality. Instead of the poorly aligned dark-field images, I would recommend the authors to repeat the analysis by taking well-aligned and carefully focused bright field images to show the nanocrystalline microstructure.

2.       Is it possible to provide the friction curves?

3.       The worn surface analysis was not provided. Did the frictional heating make any change to the MPT induced nanocrystalline?

Reviewer 2 Report

Generally the article is at an low level in the current version. The research methodology is presented chaotically and described in such a way that it cannot be repeated. The presented results do not have any statistical analysis, which makes them unreliable. The article needs to be completely rewritten.

Critical comments to the article:

1. The introduction is hardly understandable. It partially refers to the literature (it is obviously correct), but on page 2 - the third paragraph - the information from the literature is mixed with the fragmentarily presented research methodology. In general, this paragraph begins with the phrase "MPT background". What background? Was it supposed to be a subsection? Some information refers to literature, some to own research - it is not very transparent.

2. The first sentence of the introduction is incorrect: "The reliability of the products during operation significantly affects the quality of the contacting surfaces of the machines, which is determined by both stereometry (geometry) of surfaces and the properties of the surface layers [1 – 3]." The reliability of the products does not affect the quality of the contact surfaces of the machines. Reliability is determined by the quality of the contact.

3. The introduction already describes the research methodology, but the expressions: special tool, technological medium are too general. Especially the expression "special tool" is unacceptable. How is this to be interpreted by the reader?

4. How is the load of 0.5-0.8 GPa realized?

5. Figures 1 and 2 are too small. For this reason, they are illegible.

6. In chapter 2 the expression "special device" appears. How is this to be interpreted by the reader?

7. All symbols used in Table 1 are not explained.

8. Page 8, last sentence of the first paragraph is unfinished: "Such diffrac-246 tion patterns are".

9. Are the results presented, the mean values? Was there any repeatability of the research?

10. Why was such a steel and such a cast iron chosen for testing?

11. What was the friction distance in tribological studies? The time of 6 hours quoted is relative and cannot be used for comparison with other studies.

12. How were the samples prepared for the weight loss measurement? What about wear products that accumulate on the surface? Is it a relative or absolute loss? Figure 7 shows that this is an absolute loss. How does it compare then? After all, the starting masses are different.

Reviewer 3 Report

1. Similarity is a little bit high (27%), make it to less than 20% and from a single paper, not more than 4%. Check the attached similarity report.

2. The quality of the figures is too low. Enhance the quality of the figures and also increase the font size inside the figures.

3. Literature review needs to include several recent, relevant publications (high impact) highlighting their key findings. The current version only discussed general aspects while the review of each from several papers is necessary. You may provide a review summary table consisting of a column for the comments or key conclusions. 

4. Enhance the objective and novelty of the work in the introduction section.

5. The conclusion stated in this article is more a summary of the results, than a true conclusion. The conclusion part should contain findings and recommendations for this field.

6. Improve language throughout the manuscript.

Comments for author File: Comments.pdf