Investigating the Effects of Graphene Nanoplatelets and Al4C3 on the Tribological Performance of Aluminum-Based Nanocomposites
Round 1
Reviewer 1 Report
This research looked at how graphene nano-platelets (GNPs) affected the tribological properties of nanocomposites made of aluminum, both those that had been heated after extrusion and those that hadn't. Additionally, it was looking into how the Al/GNPs nanocomposite's tribological activity was impacted by the aluminium carbide (Al4C3) that forms at the nanoscale.
The current study is well suited to be published in Metals Journal.
The following corrections are required before acceptance.
1. I advised you to don't use pronouns like We, I, They, etc. in the entire manuscript.
2. Abstract is very general. Write the specific novelty and add the important comparative results in %.
3. Introduction contains many small paragraphs, merge them. Also, a critical review is required to address the literature gap. Also, the objective of the current work must be included point-wise in last part of the introduction.
4. In section 2, Add the real images of powder. Also, add the SEM images.
5. In section 2, Add the pictorial view to prepare the sample. Use real images for that.
6. What are 1, 2, and 3 in SEM images (Figure 1)? Give their names in Figures.
7. Discussion of microstructure (SECTION 3.1) is inadequate and needs comparative discussion with previously published literature.
8. Wear Behaviour must be discussed with agreement and disagreement of literature. Also, address the wear mechanism in detail. Add some important wear SEM images.
9. Quality of Figure 5 and 6 need to be improved.
10. Write a point-wise Conclusion. Also, add the future scope.
Overall, major revision is required.
Minor editing is required.
Author Response
Dear Reviewer,
Thank you for your kind comments and suggestions about our manuscript with the title “Investigating the effects of graphene nano-platelets and Al4C3 on the tribological performance of aluminum-based nanocomposites”. It would help us to improve the quality of our manuscript. We have inspected the whole manuscript and tried our best to revise carefully according to your comments in our revised version of the manuscript.
- I advised you to don't use pronouns like We, I, They, etc. in the entire manuscript.
Response: Thank you for your feedback regarding our manuscript. We appreciate your suggestion to avoid using pronouns throughout the text. We have carefully reviewed the manuscript and made the necessary changes to eliminate such pronouns, ensuring that the language is more objective and concise.
- Abstract is very general. Write the specific novelty and add the important comparative results in %.
Response: Thank you for your comment. We appreciate your feedback and have made the necessary revisions to the abstract to highlight the specific novelty of our study and provide important comparative results in percentage. We hope that these changes have improved the clarity and value of our research.
- Introduction contains many small paragraphs, merge them. Also, a critical review is required to address the literature gap. Also, the objective of the current work must be included point-wise in last part of the introduction.
Response: Thank you for your feedback and suggestions. We have conducted a critical review of the literature to address any gaps and provide more context to our study. Regarding the objective of the current work, we have revised the objective of the current work in the last part of the introduction to include a clear and concise point-wise outline of our aims and objectives. This will help the reader to better understand the scope and significance of our study. We appreciate your valuable input and will ensure that these changes are made to enhance the quality of our work.
- In section 2, Add the real images of powder. Also, add the SEM images.
Response: We appreciate your feedback, and we have carefully reviewed and revised the manuscript accordingly. We greatly appreciate your input and have taken it into careful consideration. In response to your suggestion, we have added real images of the powder and SEM images of cross sections in section 2. We believe that these additions will provide better visual aids and help readers better understand our study.
- In section 2, Add the pictorial view to prepare the sample. Use real images for that.
Response: Thank you for your feedback. We have carefully reviewed and revised the manuscript according to your suggestions. We have added a real image of the bars of Al/GNPs in section 2. Additionally, we have included a scheme of the production process for better visualization. We hope that these additions will provide a clearer understanding of our study. Please let us know if you have any further suggestions. Thank you for your time and valuable input.
- What are 1, 2, and 3 in SEM images (Figure 1)? Give their names in Figures.
Response: Thank you for your comments and suggestions regarding our manuscript. We have revised the caption of Figure 1 to include a clear explanation of the numbers 1, 2, and 3, which indicate each zone of the EDS analysis.
- Discussion of microstructure (SECTION 3.1) is inadequate and needs comparative discussion with previously published literature.
Response: Thank you for your feedback and constructive criticism. We appreciate your suggestions and have revised Section 3.1 to include a more detailed discussion of the microstructure and comparative analysis with previously published literature. We have carefully reviewed and incorporated the relevant literature into the discussion to provide a more comprehensive understanding of our findings. We hope that our revisions address your concerns and improve the quality of the manuscript. Thank you again for your valuable input.
- Wear Behaviour must be discussed with agreement and disagreement of literature. Also, address the wear mechanism in detail. Add some important wear SEM images.
Response: Thank you for your valuable feedback. We have already discussed the wear behaviour of our samples in section 3.1, where we compared our results with the existing literature and explained the possible wear mechanisms involved. We have also added some important low magnification SEM images of the worn surfaces in figure 3. We hope that this addresses your concern and clarifies our contribution.
- Quality of Figure 5 and 6 need to be improved.
Response: Certainly, we have taken note of the comment regarding the quality of Figure 5 and Figure 6 and have made the necessary improvements to these images. We have worked to ensure that they are now of higher quality and clarity, so that they better support the content of the paper. Thank you for bringing this to our attention and we hope that these changes are satisfactory.
- Write a point-wise Conclusion. Also, add the future scope.
Response: Thank you for your suggestion. We have revised the conclusion section to include a point-wise summary of our findings and the future scope of our work.
Thank you for your time and attention. We hope that this revision addresses your concern and improves the clarity of our manuscript. Please let us know if you have any further comments or suggestions.
Reviewer 2 Report
In the “Results and Discussion” paragraph, a statement of experimental data is given without explanations and assumptions for further use. For a more complete understanding of the effects obtained, it is necessary to compare the obtained experimental results with the results of other scientific teams. It is possible to give a brief comparison and analysis with other nano-platelets.
In the “Conclusions” paragraph, you should write ways to further use the results obtained in practice.
General impression of the article:
The article is written at a good scientific level, the material is presented consistently and visually, in a readable and understandable form, meets the requirements and can be published in the journal Metals.
Author Response
Dear Reviewer,
Thank you for your valuable feedback and suggestions on our manuscript titled “Investigating the effects of graphene nano-platelets and Al4C3 on the tribological performance of aluminum-based nanocomposites”. It would help us to improve the quality of our manuscript. We greatly appreciate your time and effort in providing us with your insightful comments.
- In the “Results and Discussion” paragraph, a statement of experimental data is given without explanations and assumptions for further use. For a more complete understanding of the effects obtained, it is necessary to compare the obtained experimental results with the results of other scientific teams. It is possible to give a brief comparison and analysis with other nano-platelets.
Response: Thank you for your valuable feedback regarding the revision. We agree that providing a comparison of the obtained experimental results with the results of other scientific teams would enhance the understanding of the effects obtained. We will include a brief comparison and analysis with other nano-platelets in the “Results and Discussion” paragraph to provide a more complete understanding of the effects obtained. We appreciate your input and look forward to improving the quality of our study.
- In the “Conclusions” paragraph, you should write ways to further use the results obtained in practice.
Response: We appreciate your suggestion to include ways to further use the results obtained in practice in the Conclusions section of our manuscript. However, we would like to clarify that our study mainly focused on the investigation of the tribological behavior of aluminum-based nanocomposites with the addition of graphene nano-platelets and Al4C3. As our results are preliminary and obtained under controlled laboratory conditions, they are not intended for specific practical applications at this stage. Nonetheless, we believe that our findings provide a promising direction for further research and development of aluminum-based nanocomposites with enhanced tribological properties. In the Conclusions section, we have highlighted the potential of our results to inform future studies on the optimization of the composition and manufacturing process of aluminum-based nanocomposites for practical applications in various industries.
Your feedback has been incredibly helpful in improving the overall quality of our manuscript. We have thoroughly reviewed the entire manuscript and have taken all of your comments and suggestions into consideration. As a result, we have carefully revised the manuscript, addressing all the points raised in your review, to ensure that it meets the highest standards.
Once again, we would like to express our gratitude for your contribution to our manuscript. Your constructive criticism and feedback have been invaluable to us, and we hope that our revised version will meet your expectations.
Reviewer 3 Report
The manuscript deals with the effect of graphene nanopellets additions to the tribological performance of aluminum. It is a continuation of a previously published article on a similar issue (the reinforcing effect of graphene nanopellets on the mechanical properties of aluminum). In addition to the influence of the graphene content on the tribological performance of the composite material obtained by powder mixing and subsequent hot extrusion, the authors present relevant results of its post-manufacturing heat treated state (annealing at 610 °C).
At first, the issue addressed could be of interest for the readers of Metals. However, the manuscript cannot be published in its present form. It needs substantial reconstruction and re-submission. Several points of the manuscript need a more thorough approach in order to render a new version to be considered suitable for publication:
A crucial question concerns the choice of the annealing temperature. It is not clear, why the authors have chosen such a relevantly high temperature (>90 % of the melting temperature of the base metal). Have the authors taken into account the possible grain growth of Al and the decrease of its mechanical properties eventually taking place?
For the experimental configuration, the authors used the tested material in the form of a pin, having a spherical tip. Obviously, in order to obtain such geometry the authors had to machine the previously obtained material (before and after annealing). What was the machining process performed? Has it introduced structural flaws to the material? Has it affected the roughness of the pin to be tested? All these issues have a critical role on the wear mechanisms activated.
The authors tested graphene-nanopellet composites under the same conditions (applied load: 30N, linear speed: 0.9m/s, sliding distance: 540m) using as counterbody an EN31 steel grade, hardened to 62 HRC, with a surface roughness (Ra) of 1.6 μm. How have these parameters been chosen? Did the authors follow a certain technical specification, not cited in the manuscript? Isn’t a roughness of 1.6 μm rather too high for such kind of studies?
In the results and discussion section, the authors started to present their experimental findings by the presentation of the morphology of the worn surfaces, under the subtitle “Microstructure”. First of all, what is presented there is not at all observations of the microstructure. The whole description is rather speculative, since it should follow the quantitative results of friction coefficient and wear that is attempting to interpret. The XRD pattern presented in Fig. 3 has no connection to the previous paragraph. In the graph, the existence of the amorphous phase is not “labeled as A”, as mentioned in the relevant legend. Similar remarks concern HRTEM analysis (P.8, l230-238 and Fig. 4).
The presentation of the results concerning pin-on-disk testing (section 3.2; P.8, L.239 to P.9, L 296 and Figs 5, 6), are not clear and rather confusing. Both Figs should be split in two: one set of data concerning the as-obtained material and a second one concerning those of the heat-treated material.
Finally, the manuscript suffers from linguistic errors concerning even the scientific approach presented. Al4C3 is not an addition, -according to what the authors present- it is the product of a metallurgical reaction between the metallic matrix and the graphene nano-pellets, that is strongly activated in the near-melting temperature of annealing.
The manuscript suffers from linguistic errors concerning even the scientific approach presented, e.g. Al4C3 is not an addition
Author Response
Thank you for taking the time to review our manuscript, "Investigating the effects of graphene nano-platelets and Al4C3 on the tribological performance of aluminum-based nanocomposites." We appreciate your comments and suggestions, which have helped us improve the quality of our work. We carefully examined the manuscript and made revisions based on your feedback in the revised version.
- A crucial question concerns the choice of the annealing temperature. It is not clear, why the authors have chosen such a relevantly high temperature (>90 % of the melting temperature of the base metal). Have the authors taken into account the possible grain growth of Al and the decrease of its mechanical properties eventually taking place?
Response: Thank you for your question regarding our choice of annealing temperature in our study. A relatively high temperature for annealing was chosen 610 ℃, because we found that aluminum carbide is obtained at it for a reasonable retention time (three hours). We have previously done experiments at a temperature of 550 ℃ and a holding time of 3 hours, but we did not record Al4C3. The respected reviewer is correct in noting that under these conditions the aluminum grain grows and the strength properties of the composite decrease. The strengthening effect of aluminum carbide on the composite is less than the softening effect of the grown aluminum grain.
- For the experimental configuration, the authors used the tested material in the form of a pin, having a spherical tip. Obviously, in order to obtain such geometry the authors had to machine the previously obtained material (before and after annealing). What was the machining process performed? Has it introduced structural flaws to the material? Has it affected the roughness of the pin to be tested? All these issues have a critical role on the wear mechanisms activated.
Response: Thank you for your question regarding the experimental configuration used in our study. We machined the tested material using a lathe to obtain the spherical tip geometry. The machining process was carefully designed to minimize any potential structural flaws that could affect the wear mechanisms. We used a low feed rate and a high cutting speed to avoid any plastic deformation or microstructural damage. We appreciate your attention to these critical details and are confident that our experimental procedures were carefully designed and executed to obtain reliable and accurate results.
- The authors tested graphene-nanopellet composites under the same conditions (applied load: 30N, linear speed: 0.9m/s, sliding distance: 540m) using as counterbody an EN31 steel grade, hardened to 62 HRC, with a surface roughness (Ra) of 1.6 μm. How have these parameters been chosen? Did the authors follow a certain technical specification, not cited in the manuscript? Isn’t a roughness of 1.6 μm rather too high for such kind of studies?
Response: Thank you for your question. The parameters were chosen based on previous studies in the literature that have used similar test conditions to evaluate the wear behavior. The applied load of 30 N is within the range of typical loads reported in the literature for tribological testing of Al-based nanocomposites. However, we understand the reviewer's concern about the surface roughness of the counterbody and acknowledge that there are other values that could have been chosen. We wanted to experiment with a different roughness than what has been reported in the literature, but still use the same counterbody with the same hardness to maintain consistency with previous studies. We believe that our results still provide valuable insights into the tribological behavior of Al-based nanocomposites under these testing conditions. Once again, thank you for your insightful comments, and we appreciate the opportunity to clarify our experimental design choices.
- In the results and discussion section, the authors started to present their experimental findings by the presentation of the morphology of the worn surfaces, under the subtitle “Microstructure”. First of all, what is presented there is not at all observations of the microstructure. The whole description is rather speculative, since it should follow the quantitative results of friction coefficient and wear that is attempting to interpret. The XRD pattern presented in Fig. 3 has no connection to the previous paragraph. In the graph, the existence of the amorphous phase is not “labeled as A”, as mentioned in the relevant legend. Similar remarks concern HRTEM analysis (P.8, l230-238 and Fig. 4).
Response: Thank you for your feedback on our manuscript. We apologize for the confusion in the presentation of our experimental findings. We will revise the section on the morphology of the worn surfaces to more accurately reflect our observations and ensure that it follows the presentation of our quantitative results on friction coefficient and wear. We will also clarify the labeling of the XRD pattern and ensure that the connection to the previous paragraph is made clear. Moreover, XRD and TEM results are in themselves necessary in this study as evidence of the presence of aluminum carbide in the composite formed during the post-extrusion heat treatment. In addition, we will revise the HRTEM analysis section and Figure 4 to address the concerns you raised. We appreciate your valuable input, which will help us improve the clarity and accuracy of our manuscript.
- The presentation of the results concerning pin-on-disk testing (section 3.2; P.8, L.239 to P.9, L 296 and Figs 5, 6), are not clear and rather confusing. Both Figs should be split in two: one set of data concerning the as-obtained material and a second one concerning those of the heat-treated material.
Response: Thank you for your valuable feedback on our manuscript. We appreciate your suggestions and have carefully considered them. Regarding your comment on the presentation of the results in section 3.2 and figures 5 and 6, we apologize for any confusion caused by the colors of the bars. We will make sure to edit the figures with different colors for the two materials to improve the clarity of the data. Once again, we appreciate your comments and hope that our revisions will address your concerns.
- Finally, the manuscript suffers from linguistic errors concerning even the scientific approach presented. Al4C3 is not an addition, -according to what the authors present- it is the product of a metallurgical reaction between the metallic matrix and the graphene nano-pellets, that is strongly activated in the near-melting temperature of annealing.
Response: Thank you for your feedback on our manuscript. We appreciate you bringing the linguistic errors to our attention. We have carefully reviewed our manuscript and have made the necessary corrections. We apologize for any confusion this may have caused and we hope that the revised version of our manuscript will better reflect the scientific approach presented.
Thank you for your valuable feedback on our manuscript. We have carefully considered your suggestions and have made the necessary revisions to improve the quality and clarity of our work. We appreciate the time you took to review our manuscript and hope that the changes we made have addressed your concerns.
Round 2
Reviewer 1 Report
The authors have made required corrections. Now the current form of paper can be accepted.
Moderate corrections in English language is required.
Reviewer 3 Report
The authors have taken into consideration all the comments on the initial manuscript and the revised version is significantly improved.
