Development of Zn-Reinforced Mg Matrix Composites via High Energy Ball Milling Duration: Impact on Mechanical Properties and Biodegradability

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this study, Zn-reinforced Mg matrix composite materials were produced via powder metallurgy and the effects of milling time on Mg-Zn alloy property were investigated.

This study achieves certain originality but is insufficient for acceptance in as-received form. I think that this study should be improved in these aspects:

1. The Introduction part is unattractive and the research progress about the influences of milling time on the property of magnesium matrix composites should be summarized in order to strength the originality of this study.
2. More information in tools (for example the precision balance) such as manufacturer, city, country needs to be provided.
3. The units should be consistent. Therefore, the unit of “h” was present in Abstract. However, the unit of “hour” was also used in this study.
4. The error values for example the increased hardness values of 41.5%, 84.6%, and 100% should be provided.
5. The study is mainly at the experimental report level and further theoretical discussion should be provided in the revised manuscript.
6. The Conclusions part is too long and should be concise.

Comments on the Quality of English Language

In this study, Zn-reinforced Mg matrix composite materials were produced via powder metallurgy and the effects of milling time on Mg-Zn alloy property were investigated.

This study achieves certain originality but is insufficient for acceptance in as-received form. I think that this study should be improved in these aspects:

1. The Introduction part is unattractive and the research progress about the influences of milling time on the property of magnesium matrix composites should be summarized in order to strength the originality of this study.
2. More information in tools (for example the precision balance) such as manufacturer, city, country needs to be provided.
3. The units should be consistent. Therefore, the unit of “h” was present in Abstract. However, the unit of “hour” was also used in this study.
4. The error values for example the increased hardness values of 41.5%, 84.6%, and 100% should be provided.
5. The study is mainly at the experimental report level and further theoretical discussion should be provided in the revised manuscript.
6. The Conclusions part is too long and should be concise.

Author Response

Reviewer #1: In this study, Zn-reinforced Mg matrix composite materials were produced via powder metallurgy and the effects of milling time on Mg-Zn alloy property were investigated.

This study achieves certain originality but is insufficient for acceptance in as-received form. I think that this study should be improved in these aspects:

Comment 1: The Introduction part is unattractive and the research progress about the influences of milling time on the property of magnesium matrix composites should be summarized in order to strength the originality of this study.

Response 1: Thanks for the comment. We have implemented revisions that significantly improved the quality of the introduction part. We enhanced by inserting information from literature regarding the influences of milling time on the property of magnesium matrix composites. We expanded the reference list and discussion take place wherever needed. We hope that the present form (revised version) meets the expectations.

 

Comment 2: More information in tools (for example the precision balance) such as manufacturer, city, country needs to be provided.

Response 2: Thanks for the comment. We revised the information about tools

 

Comment 3: The units should be consistent. Therefore, the unit of “h” was present in Abstract. However, the unit of “hour” was also used in this study.

Response 3: Thank you for pointing this out. We corrected the unit and we provided consistence for all units

 

Comment 4: The error values for example the increased hardness values of 41.5%, 84.6%, and 100% should be provided.

Response 4: We appreciate the comment. We have already shown the error bars in given graphs. As Reviewer suggestion, we also included the error values in text of the manuscript.

 

Comment 5: The study is mainly at the experimental report level and further theoretical discussion should be provided in the revised manuscript.

Response 5: We would like to offer our sincere appreciation to the reviewer for dedicating their time to thoroughly evaluate our manuscript. In response to his/her valuable comment, we have implemented revisions that significantly improved the quality of the manuscript. We enhanced the reference list and expounded every discussion in greater depth wherever needed. We hope that the present form (revised version) meets the expectations. Once again, thank you very much for your effort by reviewing our paper.

 

Comment 6: The Conclusions part is too long and should be concise.

Response 6: Thanks for the comment. We entirely revised the conclusion part and more concise information regarding this study was composed accordingly.

Reviewer 2 Report

Comments and Suggestions for Authors

This paper discusses the mechanical and corrosion properties of Zn-reinforced Mg-based composites produced through various ball-milling durations via powder metallurgy. However, the paper needs specific revisions:

1. The introduction effectively introduces concepts such as magnesium alloys, magnesium-zinc alloys, and powder metallurgy. Nevertheless, it lacks a discussion on the research topic itself. It is essential to include an introduction and discussion of related studies to enhance the background and significance of the research content.

2. In line 95, "two of the most widely utilized PCA systems in the literature, stearic acid and methanol," please specify the exact literature sources.

3. Has a sintering experiment been conducted with the unmilled powder? Although the results analysis for hardness and density includes data for the 0h condition, which corresponds to the un-milled material, there is no corresponding microstructural characterization in the text. Should the paper be modified for consistency?

4. Regarding the discussion on corrosion properties, the authors are requested to elaborate on why the average corrosion rates for samples milled for 2 hours and 8 hours are very close. Moreover, severe corrosion behavior occurs on the 5th and 10th days, respectively. While the experimental results show that 4 hours of milling yields excellent overall performance, a deeper explanation is necessary for the differences observed in the control group.

5. Additionally, some formatting and grammatical adjustments are needed in the paper. For example, on page 2, line 79, "In the literature; It is revealed that…" the use of a semicolon and capitalization seems odd. In line 89, "pure magnesium POWDER" should be "pure magnesium powder." Also, please use an asterisk or ✖ for multiplication rather than the letter 'x. '

Author Response

Reviewer-2

Comments to the Author

Reviewer #2: This paper discusses the mechanical and corrosion properties of Zn-reinforced Mg-based composites produced through various ball-milling durations via powder metallurgy. However, the paper needs specific revisions:

Comment 1: The introduction effectively introduces concepts such as magnesium alloys, magnesium-zinc alloys, and powder metallurgy. Nevertheless, it lacks a discussion on the research topic itself. It is essential to include an introduction and discussion of related studies to enhance the background and significance of the research content.

Response 1: Thanks for the comment. We have implemented revisions that significantly improved the quality of the introduction part. We enhanced by inserting information from literature regarding the influences of milling time on the property of magnesium matrix composites. We expanded the reference list and discussion take place wherever needed. We hope that the present form (revised version) meets the expectations.

 

Comment 2: In line 95, "two of the most widely utilized PCA systems in the literature, stearic acid and methanol," please specify the exact literature sources.

Response 2: We appreciate this valuable comment. We included the following reference into manuscript body. (https://doi.org/10.1007/s13632-023-00962-2)

 

Comment 3:  Has a sintering experiment been conducted with the unmilled powder? Although the results analysis for hardness and density includes data for the 0h condition, which corresponds to the un-milled material, there is no corresponding microstructural characterization in the text. Should the paper be modified for consistency?

Response 3: Thanks for the comment. We implemented the information and SEM illustration about unmilled powder. We included following text into manuscript body as; The SEM analysis of the pure Mg sample sintered for 2 hours in an atmosphere-controlled tube furnace displayed the existence of pores, which are attributed to insufficient intragranular bonding. This lack of bonding appears to have led to intergranular separations. Comparable microstructural features were also reported in the study by Güneş et al., supporting the observations made in the current work. (https://doi.org/10.1007/s11106-015-9693-8)

 

Comment 4: Regarding the discussion on corrosion properties, the authors are requested to elaborate on why the average corrosion rates for samples milled for 2 hours and 8 hours are very close. Moreover, severe corrosion behavior occurs on the 5th and 10th days, respectively. While the experimental results show that 4 hours of milling yields excellent overall performance, a deeper explanation is necessary for the differences observed in the control group.

Response 4: Thanks for the detailed comment/criticism. We implemented detailed explanation regarding corrosion information as following: Ghali et al. reported that the corrosion behavior of pure magnesium and its alloys which is significantly affected by their microstructural characteristics, such as grain boundaries, phase distribution, and porosity (https://doi.org/10.1361/10599490417533). This relationship between microstructure and corrosion resistance is further supported by the findings of Hook et al., as well as the results obtained in the present study (https://doi.org/10.1002/adem.200800046). Especially, Zhang stated that corrosion commonly initiates in the α-Mg phase, which acts as the anodic region in galvanic interactions with secondary phases (https://doi.org/10.1016/S1003-6326(06)60297-5). Hence, the higher corrosion rate observed in the pure Mg sample can be attributed to the dominance of the α-Mg phase within its microstructure. As stated in the previous section based on the SEM images (Figure 4), a significant number of pores were observed in the sample obtained by sintering the powders exposed to a 2 h ball milling process. Immersion tests revealed that the most rapid material degradation occurred by the 5th day for this sample (Figure 8.a).  Song et al. stated that pores concentrated along grain boundaries are particularly susceptible to attack by aggressive ions in the immersion environment, which would further compromise structural integrity (https://doi.org/10.1016/j.corsci.2014.04.008).  These pores act as preferential sites for crack initiation and propagation.  It can be stated that a significant amount of mass loss occurred in the sample due to these regions. After the 10th day, the mass loss rate tends to stabilize, which can be attributed to the detachment of highly porous regions and the formation of a corrosion product layer that limits further interaction with the medium.

 In light of these results, it can be inferred that the amount of porosity within the structure increases over time due to the effects of pitting corrosion. Similar to the sample sintered for 2 hours, the increasing porosity may serve as a site for crack initiation and propagation, ultimately compromising structural integrity and causing a sharp rise in mass loss. As a result, a sudden increase in mass loss is observed by the end of the 10th day

 

Comment 5:  Additionally, some formatting and grammatical adjustments are needed in the paper. For example, on page 2, line 79, "In the literature; It is revealed that…" the use of a semicolon and capitalization seems odd. In line 89, "pure magnesium POWDER" should be "pure magnesium powder." Also, please use an asterisk or ✖ for multiplication rather than the letter 'x. '

Response 5: Thanks for letting us know, we appreciate it very much. We corrected the punctuation errors and an asterisk instead of the letter 'x' are used in all equations and the added text is highlighted.

Reviewer 3 Report

Comments and Suggestions for Authors

1. The title of the article should be corrected as it does not fully reflect its content. The research results presented in the article do not cover the full range of research on mechanical properties, but only on hardness of composites after various technological operations.
2. The abstract of the article should also be corrected, as it does not fully reflect the scope of the research conducted.
3. Key words should be supplemented with the type of composite tested.
4. In subsection 2.1, Production and Characterisation of Powders, they did not present the dimensions of the obtained samples after the sintering process. Table 1 should be supplemented with the powder milling times used.
5. Chapter 4, entitled as ‘Conclusions’, should be completely revised and contain the actual conclusions of the research and indications for possible practical use of the research results. The content contained in this chapter, on the other hand, is a summary and discussion of the research results obtained.

Author Response

Reviewer-3

Comments to the Author

 

Comment 1: The title of the article should be corrected as it does not fully reflect its content. The research results presented in the article do not cover the full range of research on mechanical properties, but only on hardness of composites after various technological operations.

Response 1: Thanks, you very much for the suggestion. We changed the title as ‘Development of Zn-Reinforced Mg Matrix Composites via High Energy Ball Milling Duration: Impact on Mechanical Properties and Biodegradability’

 

Comment 2: The abstract of the article should also be corrected, as it does not fully reflect the scope of the research conducted.

Response 2: Thanks for the comment. We revised the abstract and new text was added which reflects the scope the research.

 

Comment 3: Key words should be supplemented with the type of composite tested.

Response 3: Thanks for the comment. We included new keywords.

 

Comment 4: In subsection 2.1, Production and Characterisation of Powders, they did not present the dimensions of the obtained samples after the sintering process. Table 1 should be supplemented with the powder milling times used.

Response 4: Thanks for the comment. In this study, we aimed to reach highly dense structure. The sample dimension used for this study is 13 mm diameter disc shape sample with 2mm thickness. The dimension of the samples were not suitable to measure linear or volumetric shrinkage after consolidation process because the shrinkage will be in micron range. According to literature survey, there is few studies sharing the linear or volumetric shrinkage behavior due to densification process because their intention is to present the shrinkage behavior so that the sample dimension and the experimental setup (dilatometer) was tailored according to this aim. Overall, we prefer not to presents details regarding shrinkage rate or behavior of the sample after sintering process. Our aim in this research is to present the relationship between milling duration and biodegradable Mg-Zn alloys.

 

Comment 5: Chapter 4, entitled as ‘Conclusions’, should be completely revised and contain the actual conclusions of the research and indications for possible practical use of the research results. The content contained in this chapter, on the other hand, is a summary and discussion of the research results obtained.

Response 5: Thanks for the criticism. As the peer-reviewer suggestion. We revised the entire manuscript by implementing concise information related the research. We also included text about practical usage of prosed alloys in this study.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have made a great effort and all points about the manuscript raised by me are suitably responded. I recommend its acceptance for publication after the following respects have been addressed.

1. The words in some Figures including Figures 1(a) and 1(b), Figures 3c and 3(d) were small or fuzzy, which should be revised.
2. The error symbol is usually written as “±”.

Comments on the Quality of English Language

The authors have made a great effort and all points about the manuscript raised by me are suitably responded. I recommend its acceptance for publication after the following respects have been addressed.

1. The words in some Figures including Figures 1(a) and 1(b), Figures 3c and 3(d) were small or fuzzy, which should be revised.
2. The error symbol is usually written as “±”.

Author Response

Comments to the Author

Reviewer #1: The authors have made a great effort and all points about the manuscript raised by me are suitably responded. I recommend its acceptance for publication after the following respects have been addressed.

Comment 1: The words in some Figures including Figures 1(a) and 1(b), Figures 3c and 3(d) were small or fuzzy, which should be revised.

Response 1: Thanks for the comment. We have implemented revisions that significantly improved the quality of the figures and all text in figures are visible and readable.

 

Comment 2: The error symbol is usually written as “±”.

Response 2: Thanks for letting us know, we appreciate it very much. We corrected the symbol errors and an “±” instead of the '∓” are used in all text and the revised text is highlighted.

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have well addressed all the concerns raised in the previous review.  The revised manuscript can be accepted.

Author Response

Thanks a lot for your insightful comments and review