Effects of Al2O3 Addition on the Microstructure and Properties of CoCr Alloys
Round 1
Reviewer 1 Report
A well structured manuscript, in which the effect of Al2O3 particles addition on microstructure and tensile properties was considered.
The English is good enough for the review process, but it needs proofreading before it is accepted for publishing.
Reactions and mechanisms behind the different percentages of Al2O3 addition after laser cladding are rationalized and explained. However, it is not clear what reactions took place in the crucible during baking at 90°C after adding the Al2O3 powder, which made the overall particle size of the mixture become smaller! (Section 2.1, 3rd paragraph (row 117)).
How reliable do authors consider the results of EDS analysis on two adjacent points (approximately 2 μm in distance), especially when quantifying the amount of carbon (see Figure 5)?
Author Response
Response to Reviewer 1 Comments
Point 1: The English is good enough for the review process, but it needs proofreading before it is accepted for publishing.
Response 1: We would like to thank you for your efforts in reviewing our manuscript and providing helpful comments and suggestions. With regard to the language, we have gone to a professional organization for language correction. Here is the editorial certificate..
Point 2: Reactions and mechanisms behind the different percentages of Al2O3 addition after laser cladding are rationalized and explained. However, it is not clear what reactions took place in the crucible during baking at 90°C after adding the Al2O3 powder, which made the overall particle size of the mixture become smaller! (Section 2.1, 3rd paragraph (row 117)).
Response 2: Sincerely thanks for your helpful suggestion. We were really sorry for our careless mistakes. Thank you for your reminding. We did the wrong description before, and Our specific steps are: placing CoCr alloy powder in a Al2O3 crucible with a powder thickness of 10 mm. Place the crucible in an oven at 90 ℃ for 3 hours and remove it for use. The powder was prepared by gas atomization technology. CoCr alloy powder and alumina powder were melted and melted in medium frequency induction melting furnace in proportion to the atomization temperature. when the atomization temperature was reached, the molten metal liquid flowed through the nozzle of different inner diameter into the atomization zone, and the molten metal liquid was dispersed and condensed into alloy powder under the breakdown of a certain high pressure inert gas (gas argon). The purpose of putting CoCr alloy powder into crucible is to improve the superheat of the powder, because with the increase of overheat, the average particle size of the powder decreases and the powder size will be smaller.
Point 3: How reliable do authors consider the results of EDS analysis on two adjacent points (approximately 2 μm in distance), especially when quantifying the amount of carbon (see Figure 5)?
Response 3: Thank you for your careful comments on our manuscripts. We select these two points, although adjacent, but combined with XRD and EDS analysis, they are different regions, 1 point is reticulated carbide, 2 points are completely different from it. Therefore, we think that these two points are representative.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Metals-596496: Effects of Al2O3 Addition on the Microstructure and Properties of CoCr Alloys
The topic is appropriate and interesting for Metals, but there are too many changes and clarifications necessary before this article can be published:
Figures: Several figures have different parts (a, b, c, d, etc.) and, consequently, there should be a specific explanation in the figure legend. Please, revise Figures 3,5,6,8,9,14,… There are several sentences that need to include a reference: line 27 “Wiper et al. have……”; line 31: “Hedberg et al. found…..”; line 53 “Hagihara et al. found….” etc. Figure 11 is not clear. For the sake of clarity, a scheme of the samples and the points where the HV was measured is advisable. Furthermore, a better discussion is necessary. Please, include in the main text a better discussion of Figure 12. In addition, a table including the mechanical properties (yield strength, UTS,…) obtained from the different %Al2O3 and the subsequent discussion are mandatory. Please, write with subscripts Al2O3 in the Figure 1. Line 151. The equation 1 need a better explanation in the main text. Indeed, the explanation in line 162-164 “There sere generally two types of carbonized…. in Cr [25]”, should appear before Equation 1. Line 170. “…mechanical properties. [25-27] Thus…” => “…mechanical properties [25-27]. Thus…” Line 181. Figure 7 is cited before Figure 6. Thus, figures should be renumbered. Equation 2. Please, follow the same criteria in the equation (italics, non italics, etc). Please, improve the visibility of the Figures 5, 8, 9, 10,... Please, write the references according to the MDPI format. Although the number and the selection of references is adequate, it would be advisable to include some papers from the journals of MDPI editorial (Metals, Coatings, Applied Sciences, Materials, etc.) related to the topic of the manuscript.
Author Response
Response to Reviewer 2 Comments
Point 1: Figures: Several figures have different parts (a, b, c, d, etc.) and, consequently, there should be a specific explanation in the figure legend. Please, revise Figures 3,5,6,8,9,14,…
Response 1: Thank you for your comments, we have given the corresponding explanation
Point 2: There are several sentences that need to include a reference: line 27 “Wiper et al. have……”; line 31: “Hedberg et al. found…..”; line 53 “Hagihara et al. found….” etc.
Response 2: Thank you for your comments. We have made the corresponding changes.
Point 3: Figure 11 is not clear. For the sake of clarity, a scheme of the samples and the points where the HV was measured is advisable. Furthermore, a better discussion is necessary.
Response 3: The mechanical properties of the alloy were further discussed by adding the metallographic diagram of the alloy.
Point 4: Please, include in the main text a better discussion of Figure 12. In addition, a table including the mechanical properties (yield strength, UTS,…) obtained from the different %Al2O3 and the subsequent discussion are mandatory.
Response 4: We carefully analyzed the mechanical properties and listed the mechanical properties of all test groups. And made an analysis.
Point 5: Please, write with subscripts Al2O3 in the Figure 1. Line 151.
Response 5: Sincerely thanks for your helpful suggestion. We were really sorry for your careless mistakes. Thank you for your reminding. We have corrected these mistakes based on your suggestions.
Point 6: The equation 1 need a better explanation in the main text. Indeed, the explanation in line 162-164 “There sere generally two types of carbonized…. in Cr [25]”, should appear before Equation 1.
Response 6: Thanks again for your suggestion, we have modified the manuscript.
Point 7: Line 170. “…mechanical properties. [25-27] Thus…” => “…mechanical properties [25-27]. Thus…” Line 181. Figure 7 is cited before Figure 6. Thus, figures should be renumbered.
Response 7: We have modified the manuscript.
Point 8: Equation 2. Please, follow the same criteria in the equation (italics, non italics, etc).
Response 8: We have modified the manuscript according to your suggestion
Point 9: Please, improve the visibility of the Figures 5, 8, 9, 10,...
Response 9: We have adjusted the clarity of the related graph
Point 10:Please, write the references according to the MDPI format. Although the number and the selection of references is adequate, it would be advisable to include some papers from the journals of MDPI editorial (Metals, Coatings, Applied Sciences, Materials, etc.) related to the topic of the manuscript.
Response 10: We have modified the reference format in accordance with the MDPI format requirements. We reviewed the MDPI related articles and cited them in the manuscript.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Metals-596496: Effects of Al2O3 Addition on the Microstructure and Properties of CoCr Alloys
Several of my previous comments were not considered or clarified. Besides, New doubts have arisen with the new document:
Write the references according to the MDPI format. Review the whole document, since the format of the references used in the main text is not correct. Figure 11 is not clear. For the sake of clarity, a scheme of the samples indicating the points where the HV was measured is advisable. Furthermore, a better discussion is necessary. Please, use the same number of decimals in each column of Table 1. Figure 13. Please write MPa correctly (capital letter P in vertical axis). Figure 13. The stress-strain curve in the case of 5% makes no sense (last increase at the end of the curve). Please, include a justification of this subject in the main text. In addition, in relation to Figure 13, have the authors used actual stress-strain data? and for the calculation of Table 1? Please justify this comment widely. Although the number and the selection of references is adequate, it would be advisable to include some more papers from the journals of MDPI editorial (Metals, Coatings, Applied Sciences, Materials, etc.) related to the topic of the manuscript.
Author Response
Response to Reviewer 2 Comments
Point 1: Write the references according to the MDPI format. Review the whole document, since the format of the references used in the main text is not correct
Response 1: We apologize for our carelessness. We have changed the format.
Point 2: Figure 11 is not clear. For the sake of clarity, a scheme of the samples indicating the points where the HV was measured is advisable. Furthermore, a better discussion is necessary.
Response 2: Thank you very much for your comments, and we apologize for the changes we made last time. We have drawn a schematic diagram of hardness and made further analysis.
Point 3: Please, use the same number of decimals in each column of Table 1.
Response 3: Thank you again for your comments. We have used the same decimal places.
Point 4: Figure 13. Please write MPa correctly (capital letter P in vertical axis). Figure 13. The stress-strain curve in the case of 5% makes no sense (last increase at the end of the curve). Please, include a justification of this subject in the main text. In addition, in relation to Figure 13, have the authors used actual stress-strain data? and for the calculation of Table 1? Please justify this comment widely.
Response 4: We have made corresponding changes to the diagram. With regard to the problem of the last small variation in the 5% scale diagram, we analyze it because of the inhomogeneity of the tissue from the boundary to the center, such as the hardness of the sample described in the previous article is different from the boundary to the center, and the microstructure is also different. Especially in this proportion, the tissue is relatively small. Therefore, we speculate that there is a small change in the causes of the tissue in the tensile process. We provide the force and displacement curves given by the measuring software in the original data to prove the authenticity of our data. In order to avoid ambiguity, we removed part of the curve with a small variation. In addition, the data in Table 1 are calculated according to the corresponding calculation rules and the actual measurement data.
Point 5: Although the number and the selection of references is adequate, it would be advisable to include some more papers from the journals of MDPI editorial (Metals, Coatings, Applied Sciences, Materials, etc.) related to the topic of the manuscript.
Response 5: We reviewed the relevant papers in MDPI and quoted some of them in our manuscripts.
Author Response File: Author Response.pdf
Round 3
Reviewer 2 Report
The paper can be published in present form.
Many thanks.
